Installing on bare metal
Installing OpenShift Container Platform on bare metal
Abstract
Chapter 1. Preparing for bare metal cluster installation
1.1. Prerequisites
- You reviewed details about the OpenShift Container Platform installation and update processes.
- You have read the documentation on selecting a cluster installation method and preparing it for users.
1.2. Planning a bare metal cluster for OpenShift Virtualization
If you will use OpenShift Virtualization, it is important to be aware of several requirements before you install your bare metal cluster.
If you want to use live migration features, you must have multiple worker nodes at the time of cluster installation. This is because live migration requires the cluster-level high availability (HA) flag to be set to true. The HA flag is set when a cluster is installed and cannot be changed afterwards. If there are fewer than two worker nodes defined when you install your cluster, the HA flag is set to false for the life of the cluster.
NoteYou can install OpenShift Virtualization on a single-node cluster, but single-node OpenShift does not support high availability.
- Live migration requires shared storage. Storage for OpenShift Virtualization must support and use the ReadWriteMany (RWX) access mode.
- If you plan to use Single Root I/O Virtualization (SR-IOV), ensure that your network interface controllers (NICs) are supported by OpenShift Container Platform.
1.3. NIC partitioning for SR-IOV devices (Technology Preview)
OpenShift Container Platform can be deployed on a server with a dual port network interface card (NIC). You can partition a single, high-speed dual port NIC into multiple virtual functions (VFs) and enable SR-IOV.
Currently, it is not possible to assign virtual functions (VF) for system services such as OVN-Kubernetes and assign other VFs created from the same physical function (PF) to pods connected to the SR-IOV Network Operator.
This feature supports the use of bonds for high availability with the Link Aggregation Control Protocol (LACP).
Only one LACP can be declared by physical NIC.
An OpenShift Container Platform cluster can be deployed on a bond interface with 2 VFs on 2 physical functions (PFs) using the following methods:
Agent-based installer
NoteThe minimum required version of
nmstate
is:-
1.4.2-4
for RHEL 8 versions -
2.2.7
for RHEL 9 versions
-
- Installer-provisioned infrastructure installation
- User-provisioned infrastructure installation
Support for Day 1 operations associated with enabling NIC partitioning for SR-IOV devices is a Technology Preview feature only. Technology Preview features are not supported with Red Hat production service level agreements (SLAs) and might not be functionally complete. Red Hat does not recommend using them in production. These features provide early access to upcoming product features, enabling customers to test functionality and provide feedback during the development process.
For more information about the support scope of Red Hat Technology Preview features, see Technology Preview Features Support Scope.
1.4. Choosing a method to install OpenShift Container Platform on bare metal
The OpenShift Container Platform installation program offers four methods for deploying a cluster:
- Interactive: You can deploy a cluster with the web-based Assisted Installer. This is the recommended approach for clusters with networks connected to the internet. The Assisted Installer is the easiest way to install OpenShift Container Platform, it provides smart defaults, and it performs pre-flight validations before installing the cluster. It also provides a RESTful API for automation and advanced configuration scenarios.
- Local Agent-based: You can deploy a cluster locally with the agent-based installer for air-gapped or restricted networks. It provides many of the benefits of the Assisted Installer, but you must download and configure the agent-based installer first. Configuration is done with a commandline interface. This approach is ideal for air-gapped or restricted networks.
- Automated: You can deploy a cluster on installer-provisioned infrastructure and the cluster it maintains. The installer uses each cluster host’s baseboard management controller (BMC) for provisioning. You can deploy clusters with both connected or air-gapped or restricted networks.
- Full control: You can deploy a cluster on infrastructure that you prepare and maintain, which provides maximum customizability. You can deploy clusters with both connected or air-gapped or restricted networks.
The clusters have the following characteristics:
- Highly available infrastructure with no single points of failure is available by default.
- Administrators maintain control over what updates are applied and when.
See Installation process for more information about installer-provisioned and user-provisioned installation processes.
1.4.1. Installing a cluster on installer-provisioned infrastructure
You can install a cluster on bare metal infrastructure that is provisioned by the OpenShift Container Platform installation program, by using the following method:
- Installing an installer-provisioned cluster on bare metal: You can install OpenShift Container Platform on bare metal by using installer provisioning.
1.4.2. Installing a cluster on user-provisioned infrastructure
You can install a cluster on bare metal infrastructure that you provision, by using one of the following methods:
- Installing a user-provisioned cluster on bare metal: You can install OpenShift Container Platform on bare metal infrastructure that you provision. For a cluster that contains user-provisioned infrastructure, you must deploy all of the required machines.
- Installing a user-provisioned bare metal cluster with network customizations: You can install a bare metal cluster on user-provisioned infrastructure with network-customizations. By customizing your network configuration, your cluster can coexist with existing IP address allocations in your environment and integrate with existing MTU and VXLAN configurations. Most of the network customizations must be applied at the installation stage.
- Installing a user-provisioned bare metal cluster on a restricted network: You can install a user-provisioned bare metal cluster on a restricted or disconnected network by using a mirror registry. You can also use this installation method to ensure that your clusters only use container images that satisfy your organizational controls on external content.
Chapter 2. Installing a user-provisioned cluster on bare metal
In OpenShift Container Platform 4.13, you can install a cluster on bare metal infrastructure that you provision.
While you might be able to follow this procedure to deploy a cluster on virtualized or cloud environments, you must be aware of additional considerations for non-bare metal platforms. Review the information in the guidelines for deploying OpenShift Container Platform on non-tested platforms before you attempt to install an OpenShift Container Platform cluster in such an environment.
2.1. Prerequisites
- You reviewed details about the OpenShift Container Platform installation and update processes.
- You read the documentation on selecting a cluster installation method and preparing it for users.
If you use a firewall, you configured it to allow the sites that your cluster requires access to.
NoteBe sure to also review this site list if you are configuring a proxy.
2.2. Internet access for OpenShift Container Platform
In OpenShift Container Platform 4.13, you require access to the internet to install your cluster.
You must have internet access to:
- Access OpenShift Cluster Manager Hybrid Cloud Console to download the installation program and perform subscription management. If the cluster has internet access and you do not disable Telemetry, that service automatically entitles your cluster.
- Access Quay.io to obtain the packages that are required to install your cluster.
- Obtain the packages that are required to perform cluster updates.
If your cluster cannot have direct internet access, you can perform a restricted network installation on some types of infrastructure that you provision. During that process, you download the required content and use it to populate a mirror registry with the installation packages. With some installation types, the environment that you install your cluster in will not require internet access. Before you update the cluster, you update the content of the mirror registry.
Additional resources
- See Installing a user-provisioned bare metal cluster on a restricted network for more information about performing a restricted network installation on bare metal infrastructure that you provision.
2.3. Requirements for a cluster with user-provisioned infrastructure
For a cluster that contains user-provisioned infrastructure, you must deploy all of the required machines.
This section describes the requirements for deploying OpenShift Container Platform on user-provisioned infrastructure.
2.3.1. Required machines for cluster installation
The smallest OpenShift Container Platform clusters require the following hosts:
Hosts | Description |
---|---|
One temporary bootstrap machine | The cluster requires the bootstrap machine to deploy the OpenShift Container Platform cluster on the three control plane machines. You can remove the bootstrap machine after you install the cluster. |
Three control plane machines | The control plane machines run the Kubernetes and OpenShift Container Platform services that form the control plane. |
At least two compute machines, which are also known as worker machines. | The workloads requested by OpenShift Container Platform users run on the compute machines. |
As an exception, you can run zero compute machines in a bare metal cluster that consists of three control plane machines only. This provides smaller, more resource efficient clusters for cluster administrators and developers to use for testing, development, and production. Running one compute machine is not supported.
To maintain high availability of your cluster, use separate physical hosts for these cluster machines.
The bootstrap and control plane machines must use Red Hat Enterprise Linux CoreOS (RHCOS) as the operating system. However, the compute machines can choose between Red Hat Enterprise Linux CoreOS (RHCOS), Red Hat Enterprise Linux (RHEL) 8.6 and later.
Note that RHCOS is based on Red Hat Enterprise Linux (RHEL) 9.2 and inherits all of its hardware certifications and requirements. See Red Hat Enterprise Linux technology capabilities and limits.
2.3.2. Minimum resource requirements for cluster installation
Each cluster machine must meet the following minimum requirements:
Machine | Operating System | CPU [1] | RAM | Storage | Input/Output Per Second (IOPS)[2] |
---|---|---|---|---|---|
Bootstrap | RHCOS | 4 | 16 GB | 100 GB | 300 |
Control plane | RHCOS | 4 | 16 GB | 100 GB | 300 |
Compute | RHCOS, RHEL 8.6 and later [3] | 2 | 8 GB | 100 GB | 300 |
- One CPU is equivalent to one physical core when simultaneous multithreading (SMT), or Hyper-Threading, is not enabled. When enabled, use the following formula to calculate the corresponding ratio: (threads per core × cores) × sockets = CPUs.
- OpenShift Container Platform and Kubernetes are sensitive to disk performance, and faster storage is recommended, particularly for etcd on the control plane nodes which require a 10 ms p99 fsync duration. Note that on many cloud platforms, storage size and IOPS scale together, so you might need to over-allocate storage volume to obtain sufficient performance.
- As with all user-provisioned installations, if you choose to use RHEL compute machines in your cluster, you take responsibility for all operating system life cycle management and maintenance, including performing system updates, applying patches, and completing all other required tasks. Use of RHEL 7 compute machines is deprecated and has been removed in OpenShift Container Platform 4.10 and later.
As of OpenShift Container Platform version 4.13, RHCOS is based on RHEL version 9.2, which updates the micro-architecture requirements. The following list contains the minimum instruction set architectures (ISA) that each architecture requires:
- x86-64 architecture requires x86-64-v2 ISA
- ARM64 architecture requires ARMv8.0-A ISA
- IBM Power architecture requires Power 9 ISA
- s390x architecture requires z14 ISA
For more information, see RHEL Architectures.
If an instance type for your platform meets the minimum requirements for cluster machines, it is supported to use in OpenShift Container Platform.
Additional resources
2.3.3. Certificate signing requests management
Because your cluster has limited access to automatic machine management when you use infrastructure that you provision, you must provide a mechanism for approving cluster certificate signing requests (CSRs) after installation. The kube-controller-manager
only approves the kubelet client CSRs. The machine-approver
cannot guarantee the validity of a serving certificate that is requested by using kubelet credentials because it cannot confirm that the correct machine issued the request. You must determine and implement a method of verifying the validity of the kubelet serving certificate requests and approving them.
Additional resources
- See Configuring a three-node cluster for details about deploying three-node clusters in bare metal environments.
- See Approving the certificate signing requests for your machines for more information about approving cluster certificate signing requests after installation.
2.3.4. Requirements for baremetal clusters on vSphere
Ensure you enable the disk.EnableUUID
parameter on all virtual machines in your cluster.
Additional resources
-
See Installing RHCOS and starting the OpenShift Container Platform bootstrap process for details on setting the
disk.EnableUUID
parameter’s value toTRUE
on VMware vSphere for user-provisioned infrastructure.
2.3.5. Networking requirements for user-provisioned infrastructure
All the Red Hat Enterprise Linux CoreOS (RHCOS) machines require networking to be configured in initramfs
during boot to fetch their Ignition config files.
During the initial boot, the machines require an IP address configuration that is set either through a DHCP server or statically by providing the required boot options. After a network connection is established, the machines download their Ignition config files from an HTTP or HTTPS server. The Ignition config files are then used to set the exact state of each machine. The Machine Config Operator completes more changes to the machines, such as the application of new certificates or keys, after installation.
It is recommended to use a DHCP server for long-term management of the cluster machines. Ensure that the DHCP server is configured to provide persistent IP addresses, DNS server information, and hostnames to the cluster machines.
If a DHCP service is not available for your user-provisioned infrastructure, you can instead provide the IP networking configuration and the address of the DNS server to the nodes at RHCOS install time. These can be passed as boot arguments if you are installing from an ISO image. See the Installing RHCOS and starting the OpenShift Container Platform bootstrap process section for more information about static IP provisioning and advanced networking options.
The Kubernetes API server must be able to resolve the node names of the cluster machines. If the API servers and worker nodes are in different zones, you can configure a default DNS search zone to allow the API server to resolve the node names. Another supported approach is to always refer to hosts by their fully-qualified domain names in both the node objects and all DNS requests.
2.3.5.1. Setting the cluster node hostnames through DHCP
On Red Hat Enterprise Linux CoreOS (RHCOS) machines, the hostname is set through NetworkManager. By default, the machines obtain their hostname through DHCP. If the hostname is not provided by DHCP, set statically through kernel arguments, or another method, it is obtained through a reverse DNS lookup. Reverse DNS lookup occurs after the network has been initialized on a node and can take time to resolve. Other system services can start prior to this and detect the hostname as localhost
or similar. You can avoid this by using DHCP to provide the hostname for each cluster node.
Additionally, setting the hostnames through DHCP can bypass any manual DNS record name configuration errors in environments that have a DNS split-horizon implementation.
2.3.5.2. Network connectivity requirements
You must configure the network connectivity between machines to allow OpenShift Container Platform cluster components to communicate. Each machine must be able to resolve the hostnames of all other machines in the cluster.
This section provides details about the ports that are required.
In connected OpenShift Container Platform environments, all nodes are required to have internet access to pull images for platform containers and provide telemetry data to Red Hat.
Protocol | Port | Description |
---|---|---|
ICMP | N/A | Network reachability tests |
TCP |
| Metrics |
|
Host level services, including the node exporter on ports | |
| The default ports that Kubernetes reserves | |
| openshift-sdn | |
UDP |
| VXLAN |
| Geneve | |
|
Host level services, including the node exporter on ports | |
| IPsec IKE packets | |
| IPsec NAT-T packets | |
|
Network Time Protocol (NTP) on UDP port
If an external NTP time server is configured, you must open UDP port | |
TCP/UDP |
| Kubernetes node port |
ESP | N/A | IPsec Encapsulating Security Payload (ESP) |
Protocol | Port | Description |
---|---|---|
TCP |
| Kubernetes API |
Protocol | Port | Description |
---|---|---|
TCP |
| etcd server and peer ports |
NTP configuration for user-provisioned infrastructure
OpenShift Container Platform clusters are configured to use a public Network Time Protocol (NTP) server by default. If you want to use a local enterprise NTP server, or if your cluster is being deployed in a disconnected network, you can configure the cluster to use a specific time server. For more information, see the documentation for Configuring chrony time service.
If a DHCP server provides NTP server information, the chrony time service on the Red Hat Enterprise Linux CoreOS (RHCOS) machines read the information and can sync the clock with the NTP servers.
Additional resources
2.3.6. User-provisioned DNS requirements
In OpenShift Container Platform deployments, DNS name resolution is required for the following components:
- The Kubernetes API
- The OpenShift Container Platform application wildcard
- The bootstrap, control plane, and compute machines
Reverse DNS resolution is also required for the Kubernetes API, the bootstrap machine, the control plane machines, and the compute machines.
DNS A/AAAA or CNAME records are used for name resolution and PTR records are used for reverse name resolution. The reverse records are important because Red Hat Enterprise Linux CoreOS (RHCOS) uses the reverse records to set the hostnames for all the nodes, unless the hostnames are provided by DHCP. Additionally, the reverse records are used to generate the certificate signing requests (CSR) that OpenShift Container Platform needs to operate.
It is recommended to use a DHCP server to provide the hostnames to each cluster node. See the DHCP recommendations for user-provisioned infrastructure section for more information.
The following DNS records are required for a user-provisioned OpenShift Container Platform cluster and they must be in place before installation. In each record, <cluster_name>
is the cluster name and <base_domain>
is the base domain that you specify in the install-config.yaml
file. A complete DNS record takes the form: <component>.<cluster_name>.<base_domain>.
.
Component | Record | Description |
---|---|---|
Kubernetes API |
| A DNS A/AAAA or CNAME record, and a DNS PTR record, to identify the API load balancer. These records must be resolvable by both clients external to the cluster and from all the nodes within the cluster. |
| A DNS A/AAAA or CNAME record, and a DNS PTR record, to internally identify the API load balancer. These records must be resolvable from all the nodes within the cluster. Important The API server must be able to resolve the worker nodes by the hostnames that are recorded in Kubernetes. If the API server cannot resolve the node names, then proxied API calls can fail, and you cannot retrieve logs from pods. | |
Routes |
| A wildcard DNS A/AAAA or CNAME record that refers to the application ingress load balancer. The application ingress load balancer targets the machines that run the Ingress Controller pods. The Ingress Controller pods run on the compute machines by default. These records must be resolvable by both clients external to the cluster and from all the nodes within the cluster.
For example, |
Bootstrap machine |
| A DNS A/AAAA or CNAME record, and a DNS PTR record, to identify the bootstrap machine. These records must be resolvable by the nodes within the cluster. |
Control plane machines |
| DNS A/AAAA or CNAME records and DNS PTR records to identify each machine for the control plane nodes. These records must be resolvable by the nodes within the cluster. |
Compute machines |
| DNS A/AAAA or CNAME records and DNS PTR records to identify each machine for the worker nodes. These records must be resolvable by the nodes within the cluster. |
In OpenShift Container Platform 4.4 and later, you do not need to specify etcd host and SRV records in your DNS configuration.
You can use the dig
command to verify name and reverse name resolution. See the section on Validating DNS resolution for user-provisioned infrastructure for detailed validation steps.
2.3.6.1. Example DNS configuration for user-provisioned clusters
This section provides A and PTR record configuration samples that meet the DNS requirements for deploying OpenShift Container Platform on user-provisioned infrastructure. The samples are not meant to provide advice for choosing one DNS solution over another.
In the examples, the cluster name is ocp4
and the base domain is example.com
.
Example DNS A record configuration for a user-provisioned cluster
The following example is a BIND zone file that shows sample A records for name resolution in a user-provisioned cluster.
Example 2.1. Sample DNS zone database
$TTL 1W @ IN SOA ns1.example.com. root ( 2019070700 ; serial 3H ; refresh (3 hours) 30M ; retry (30 minutes) 2W ; expiry (2 weeks) 1W ) ; minimum (1 week) IN NS ns1.example.com. IN MX 10 smtp.example.com. ; ; ns1.example.com. IN A 192.168.1.5 smtp.example.com. IN A 192.168.1.5 ; helper.example.com. IN A 192.168.1.5 helper.ocp4.example.com. IN A 192.168.1.5 ; api.ocp4.example.com. IN A 192.168.1.5 1 api-int.ocp4.example.com. IN A 192.168.1.5 2 ; *.apps.ocp4.example.com. IN A 192.168.1.5 3 ; bootstrap.ocp4.example.com. IN A 192.168.1.96 4 ; control-plane0.ocp4.example.com. IN A 192.168.1.97 5 control-plane1.ocp4.example.com. IN A 192.168.1.98 6 control-plane2.ocp4.example.com. IN A 192.168.1.99 7 ; compute0.ocp4.example.com. IN A 192.168.1.11 8 compute1.ocp4.example.com. IN A 192.168.1.7 9 ; ;EOF
- 1
- Provides name resolution for the Kubernetes API. The record refers to the IP address of the API load balancer.
- 2
- Provides name resolution for the Kubernetes API. The record refers to the IP address of the API load balancer and is used for internal cluster communications.
- 3
- Provides name resolution for the wildcard routes. The record refers to the IP address of the application ingress load balancer. The application ingress load balancer targets the machines that run the Ingress Controller pods. The Ingress Controller pods run on the compute machines by default.Note
In the example, the same load balancer is used for the Kubernetes API and application ingress traffic. In production scenarios, you can deploy the API and application ingress load balancers separately so that you can scale the load balancer infrastructure for each in isolation.
- 4
- Provides name resolution for the bootstrap machine.
- 5 6 7
- Provides name resolution for the control plane machines.
- 8 9
- Provides name resolution for the compute machines.
Example DNS PTR record configuration for a user-provisioned cluster
The following example BIND zone file shows sample PTR records for reverse name resolution in a user-provisioned cluster.
Example 2.2. Sample DNS zone database for reverse records
$TTL 1W @ IN SOA ns1.example.com. root ( 2019070700 ; serial 3H ; refresh (3 hours) 30M ; retry (30 minutes) 2W ; expiry (2 weeks) 1W ) ; minimum (1 week) IN NS ns1.example.com. ; 5.1.168.192.in-addr.arpa. IN PTR api.ocp4.example.com. 1 5.1.168.192.in-addr.arpa. IN PTR api-int.ocp4.example.com. 2 ; 96.1.168.192.in-addr.arpa. IN PTR bootstrap.ocp4.example.com. 3 ; 97.1.168.192.in-addr.arpa. IN PTR control-plane0.ocp4.example.com. 4 98.1.168.192.in-addr.arpa. IN PTR control-plane1.ocp4.example.com. 5 99.1.168.192.in-addr.arpa. IN PTR control-plane2.ocp4.example.com. 6 ; 11.1.168.192.in-addr.arpa. IN PTR compute0.ocp4.example.com. 7 7.1.168.192.in-addr.arpa. IN PTR compute1.ocp4.example.com. 8 ; ;EOF
- 1
- Provides reverse DNS resolution for the Kubernetes API. The PTR record refers to the record name of the API load balancer.
- 2
- Provides reverse DNS resolution for the Kubernetes API. The PTR record refers to the record name of the API load balancer and is used for internal cluster communications.
- 3
- Provides reverse DNS resolution for the bootstrap machine.
- 4 5 6
- Provides reverse DNS resolution for the control plane machines.
- 7 8
- Provides reverse DNS resolution for the compute machines.
A PTR record is not required for the OpenShift Container Platform application wildcard.
Additional resources
2.3.7. Load balancing requirements for user-provisioned infrastructure
Before you install OpenShift Container Platform, you must provision the API and application Ingress load balancing infrastructure. In production scenarios, you can deploy the API and application Ingress load balancers separately so that you can scale the load balancer infrastructure for each in isolation.
If you want to deploy the API and application Ingress load balancers with a Red Hat Enterprise Linux (RHEL) instance, you must purchase the RHEL subscription separately.
The load balancing infrastructure must meet the following requirements:
API load balancer: Provides a common endpoint for users, both human and machine, to interact with and configure the platform. Configure the following conditions:
- Layer 4 load balancing only. This can be referred to as Raw TCP or SSL Passthrough mode.
- A stateless load balancing algorithm. The options vary based on the load balancer implementation.
ImportantDo not configure session persistence for an API load balancer. Configuring session persistence for a Kubernetes API server might cause performance issues from excess application traffic for your OpenShift Container Platform cluster and the Kubernetes API that runs inside the cluster.
Configure the following ports on both the front and back of the load balancers:
Table 2.7. API load balancer Port Back-end machines (pool members) Internal External Description 6443
Bootstrap and control plane. You remove the bootstrap machine from the load balancer after the bootstrap machine initializes the cluster control plane. You must configure the
/readyz
endpoint for the API server health check probe.X
X
Kubernetes API server
22623
Bootstrap and control plane. You remove the bootstrap machine from the load balancer after the bootstrap machine initializes the cluster control plane.
X
Machine config server
NoteThe load balancer must be configured to take a maximum of 30 seconds from the time the API server turns off the
/readyz
endpoint to the removal of the API server instance from the pool. Within the time frame after/readyz
returns an error or becomes healthy, the endpoint must have been removed or added. Probing every 5 or 10 seconds, with two successful requests to become healthy and three to become unhealthy, are well-tested values.Application Ingress load balancer: Provides an ingress point for application traffic flowing in from outside the cluster. A working configuration for the Ingress router is required for an OpenShift Container Platform cluster.
Configure the following conditions:
- Layer 4 load balancing only. This can be referred to as Raw TCP or SSL Passthrough mode.
- A connection-based or session-based persistence is recommended, based on the options available and types of applications that will be hosted on the platform.
TipIf the true IP address of the client can be seen by the application Ingress load balancer, enabling source IP-based session persistence can improve performance for applications that use end-to-end TLS encryption.
Configure the following ports on both the front and back of the load balancers:
Table 2.8. Application Ingress load balancer Port Back-end machines (pool members) Internal External Description 443
The machines that run the Ingress Controller pods, compute, or worker, by default.
X
X
HTTPS traffic
80
The machines that run the Ingress Controller pods, compute, or worker, by default.
X
X
HTTP traffic
NoteIf you are deploying a three-node cluster with zero compute nodes, the Ingress Controller pods run on the control plane nodes. In three-node cluster deployments, you must configure your application Ingress load balancer to route HTTP and HTTPS traffic to the control plane nodes.
2.3.7.1. Example load balancer configuration for user-provisioned clusters
This section provides an example API and application Ingress load balancer configuration that meets the load balancing requirements for user-provisioned clusters. The sample is an /etc/haproxy/haproxy.cfg
configuration for an HAProxy load balancer. The example is not meant to provide advice for choosing one load balancing solution over another.
In the example, the same load balancer is used for the Kubernetes API and application ingress traffic. In production scenarios, you can deploy the API and application ingress load balancers separately so that you can scale the load balancer infrastructure for each in isolation.
If you are using HAProxy as a load balancer and SELinux is set to enforcing
, you must ensure that the HAProxy service can bind to the configured TCP port by running setsebool -P haproxy_connect_any=1
.
Example 2.3. Sample API and application Ingress load balancer configuration
global log 127.0.0.1 local2 pidfile /var/run/haproxy.pid maxconn 4000 daemon defaults mode http log global option dontlognull option http-server-close option redispatch retries 3 timeout http-request 10s timeout queue 1m timeout connect 10s timeout client 1m timeout server 1m timeout http-keep-alive 10s timeout check 10s maxconn 3000 listen api-server-6443 1 bind *:6443 mode tcp option httpchk GET /readyz HTTP/1.0 option log-health-checks balance roundrobin server bootstrap bootstrap.ocp4.example.com:6443 verify none check check-ssl inter 10s fall 2 rise 3 backup 2 server master0 master0.ocp4.example.com:6443 weight 1 verify none check check-ssl inter 10s fall 2 rise 3 server master1 master1.ocp4.example.com:6443 weight 1 verify none check check-ssl inter 10s fall 2 rise 3 server master2 master2.ocp4.example.com:6443 weight 1 verify none check check-ssl inter 10s fall 2 rise 3 listen machine-config-server-22623 3 bind *:22623 mode tcp server bootstrap bootstrap.ocp4.example.com:22623 check inter 1s backup 4 server master0 master0.ocp4.example.com:22623 check inter 1s server master1 master1.ocp4.example.com:22623 check inter 1s server master2 master2.ocp4.example.com:22623 check inter 1s listen ingress-router-443 5 bind *:443 mode tcp balance source server worker0 worker0.ocp4.example.com:443 check inter 1s server worker1 worker1.ocp4.example.com:443 check inter 1s listen ingress-router-80 6 bind *:80 mode tcp balance source server worker0 worker0.ocp4.example.com:80 check inter 1s server worker1 worker1.ocp4.example.com:80 check inter 1s
- 1
- Port
6443
handles the Kubernetes API traffic and points to the control plane machines. - 2 4
- The bootstrap entries must be in place before the OpenShift Container Platform cluster installation and they must be removed after the bootstrap process is complete.
- 3
- Port
22623
handles the machine config server traffic and points to the control plane machines. - 5
- Port
443
handles the HTTPS traffic and points to the machines that run the Ingress Controller pods. The Ingress Controller pods run on the compute machines by default. - 6
- Port
80
handles the HTTP traffic and points to the machines that run the Ingress Controller pods. The Ingress Controller pods run on the compute machines by default.NoteIf you are deploying a three-node cluster with zero compute nodes, the Ingress Controller pods run on the control plane nodes. In three-node cluster deployments, you must configure your application Ingress load balancer to route HTTP and HTTPS traffic to the control plane nodes.
If you are using HAProxy as a load balancer, you can check that the haproxy
process is listening on ports 6443
, 22623
, 443
, and 80
by running netstat -nltupe
on the HAProxy node.
2.4. Preparing the user-provisioned infrastructure
Before you install OpenShift Container Platform on user-provisioned infrastructure, you must prepare the underlying infrastructure.
This section provides details about the high-level steps required to set up your cluster infrastructure in preparation for an OpenShift Container Platform installation. This includes configuring IP networking and network connectivity for your cluster nodes, enabling the required ports through your firewall, and setting up the required DNS and load balancing infrastructure.
After preparation, your cluster infrastructure must meet the requirements outlined in the Requirements for a cluster with user-provisioned infrastructure section.
Prerequisites
- You have reviewed the OpenShift Container Platform 4.x Tested Integrations page.
- You have reviewed the infrastructure requirements detailed in the Requirements for a cluster with user-provisioned infrastructure section.
Procedure
If you are using DHCP to provide the IP networking configuration to your cluster nodes, configure your DHCP service.
- Add persistent IP addresses for the nodes to your DHCP server configuration. In your configuration, match the MAC address of the relevant network interface to the intended IP address for each node.
When you use DHCP to configure IP addressing for the cluster machines, the machines also obtain the DNS server information through DHCP. Define the persistent DNS server address that is used by the cluster nodes through your DHCP server configuration.
NoteIf you are not using a DHCP service, you must provide the IP networking configuration and the address of the DNS server to the nodes at RHCOS install time. These can be passed as boot arguments if you are installing from an ISO image. See the Installing RHCOS and starting the OpenShift Container Platform bootstrap process section for more information about static IP provisioning and advanced networking options.
Define the hostnames of your cluster nodes in your DHCP server configuration. See the Setting the cluster node hostnames through DHCP section for details about hostname considerations.
NoteIf you are not using a DHCP service, the cluster nodes obtain their hostname through a reverse DNS lookup.
- Ensure that your network infrastructure provides the required network connectivity between the cluster components. See the Networking requirements for user-provisioned infrastructure section for details about the requirements.
Configure your firewall to enable the ports required for the OpenShift Container Platform cluster components to communicate. See Networking requirements for user-provisioned infrastructure section for details about the ports that are required.
ImportantBy default, port
1936
is accessible for an OpenShift Container Platform cluster, because each control plane node needs access to this port.Avoid using the Ingress load balancer to expose this port, because doing so might result in the exposure of sensitive information, such as statistics and metrics, related to Ingress Controllers.
Setup the required DNS infrastructure for your cluster.
- Configure DNS name resolution for the Kubernetes API, the application wildcard, the bootstrap machine, the control plane machines, and the compute machines.
Configure reverse DNS resolution for the Kubernetes API, the bootstrap machine, the control plane machines, and the compute machines.
See the User-provisioned DNS requirements section for more information about the OpenShift Container Platform DNS requirements.
Validate your DNS configuration.
- From your installation node, run DNS lookups against the record names of the Kubernetes API, the wildcard routes, and the cluster nodes. Validate that the IP addresses in the responses correspond to the correct components.
From your installation node, run reverse DNS lookups against the IP addresses of the load balancer and the cluster nodes. Validate that the record names in the responses correspond to the correct components.
See the Validating DNS resolution for user-provisioned infrastructure section for detailed DNS validation steps.
- Provision the required API and application ingress load balancing infrastructure. See the Load balancing requirements for user-provisioned infrastructure section for more information about the requirements.
Some load balancing solutions require the DNS name resolution for the cluster nodes to be in place before the load balancing is initialized.
Additional resources
- Requirements for a cluster with user-provisioned infrastructure
- Installing RHCOS and starting the OpenShift Container Platform bootstrap process
- Setting the cluster node hostnames through DHCP
- Advanced RHCOS installation configuration
- Networking requirements for user-provisioned infrastructure
- User-provisioned DNS requirements
- Validating DNS resolution for user-provisioned infrastructure
- Load balancing requirements for user-provisioned infrastructure
2.5. Validating DNS resolution for user-provisioned infrastructure
You can validate your DNS configuration before installing OpenShift Container Platform on user-provisioned infrastructure.
The validation steps detailed in this section must succeed before you install your cluster.
Prerequisites
- You have configured the required DNS records for your user-provisioned infrastructure.
Procedure
From your installation node, run DNS lookups against the record names of the Kubernetes API, the wildcard routes, and the cluster nodes. Validate that the IP addresses contained in the responses correspond to the correct components.
Perform a lookup against the Kubernetes API record name. Check that the result points to the IP address of the API load balancer:
$ dig +noall +answer @<nameserver_ip> api.<cluster_name>.<base_domain> 1
- 1
- Replace
<nameserver_ip>
with the IP address of the nameserver,<cluster_name>
with your cluster name, and<base_domain>
with your base domain name.
Example output
api.ocp4.example.com. 604800 IN A 192.168.1.5
Perform a lookup against the Kubernetes internal API record name. Check that the result points to the IP address of the API load balancer:
$ dig +noall +answer @<nameserver_ip> api-int.<cluster_name>.<base_domain>
Example output
api-int.ocp4.example.com. 604800 IN A 192.168.1.5
Test an example
*.apps.<cluster_name>.<base_domain>
DNS wildcard lookup. All of the application wildcard lookups must resolve to the IP address of the application ingress load balancer:$ dig +noall +answer @<nameserver_ip> random.apps.<cluster_name>.<base_domain>
Example output
random.apps.ocp4.example.com. 604800 IN A 192.168.1.5
NoteIn the example outputs, the same load balancer is used for the Kubernetes API and application ingress traffic. In production scenarios, you can deploy the API and application ingress load balancers separately so that you can scale the load balancer infrastructure for each in isolation.
You can replace
random
with another wildcard value. For example, you can query the route to the OpenShift Container Platform console:$ dig +noall +answer @<nameserver_ip> console-openshift-console.apps.<cluster_name>.<base_domain>
Example output
console-openshift-console.apps.ocp4.example.com. 604800 IN A 192.168.1.5
Run a lookup against the bootstrap DNS record name. Check that the result points to the IP address of the bootstrap node:
$ dig +noall +answer @<nameserver_ip> bootstrap.<cluster_name>.<base_domain>
Example output
bootstrap.ocp4.example.com. 604800 IN A 192.168.1.96
- Use this method to perform lookups against the DNS record names for the control plane and compute nodes. Check that the results correspond to the IP addresses of each node.
From your installation node, run reverse DNS lookups against the IP addresses of the load balancer and the cluster nodes. Validate that the record names contained in the responses correspond to the correct components.
Perform a reverse lookup against the IP address of the API load balancer. Check that the response includes the record names for the Kubernetes API and the Kubernetes internal API:
$ dig +noall +answer @<nameserver_ip> -x 192.168.1.5
Example output
5.1.168.192.in-addr.arpa. 604800 IN PTR api-int.ocp4.example.com. 1 5.1.168.192.in-addr.arpa. 604800 IN PTR api.ocp4.example.com. 2
NoteA PTR record is not required for the OpenShift Container Platform application wildcard. No validation step is needed for reverse DNS resolution against the IP address of the application ingress load balancer.
Perform a reverse lookup against the IP address of the bootstrap node. Check that the result points to the DNS record name of the bootstrap node:
$ dig +noall +answer @<nameserver_ip> -x 192.168.1.96
Example output
96.1.168.192.in-addr.arpa. 604800 IN PTR bootstrap.ocp4.example.com.
- Use this method to perform reverse lookups against the IP addresses for the control plane and compute nodes. Check that the results correspond to the DNS record names of each node.
2.6. Generating a key pair for cluster node SSH access
During an OpenShift Container Platform installation, you can provide an SSH public key to the installation program. The key is passed to the Red Hat Enterprise Linux CoreOS (RHCOS) nodes through their Ignition config files and is used to authenticate SSH access to the nodes. The key is added to the ~/.ssh/authorized_keys
list for the core
user on each node, which enables password-less authentication.
After the key is passed to the nodes, you can use the key pair to SSH in to the RHCOS nodes as the user core
. To access the nodes through SSH, the private key identity must be managed by SSH for your local user.
If you want to SSH in to your cluster nodes to perform installation debugging or disaster recovery, you must provide the SSH public key during the installation process. The ./openshift-install gather
command also requires the SSH public key to be in place on the cluster nodes.
Do not skip this procedure in production environments, where disaster recovery and debugging is required.
You must use a local key, not one that you configured with platform-specific approaches such as AWS key pairs.
Procedure
If you do not have an existing SSH key pair on your local machine to use for authentication onto your cluster nodes, create one. For example, on a computer that uses a Linux operating system, run the following command:
$ ssh-keygen -t ed25519 -N '' -f <path>/<file_name> 1
- 1
- Specify the path and file name, such as
~/.ssh/id_ed25519
, of the new SSH key. If you have an existing key pair, ensure your public key is in the your~/.ssh
directory.
View the public SSH key:
$ cat <path>/<file_name>.pub
For example, run the following to view the
~/.ssh/id_ed25519.pub
public key:$ cat ~/.ssh/id_ed25519.pub
Add the SSH private key identity to the SSH agent for your local user, if it has not already been added. SSH agent management of the key is required for password-less SSH authentication onto your cluster nodes, or if you want to use the
./openshift-install gather
command.NoteOn some distributions, default SSH private key identities such as
~/.ssh/id_rsa
and~/.ssh/id_dsa
are managed automatically.If the
ssh-agent
process is not already running for your local user, start it as a background task:$ eval "$(ssh-agent -s)"
Example output
Agent pid 31874
Add your SSH private key to the
ssh-agent
:$ ssh-add <path>/<file_name> 1
- 1
- Specify the path and file name for your SSH private key, such as
~/.ssh/id_ed25519
Example output
Identity added: /home/<you>/<path>/<file_name> (<computer_name>)
Next steps
- When you install OpenShift Container Platform, provide the SSH public key to the installation program. If you install a cluster on infrastructure that you provision, you must provide the key to the installation program.
Additional resources
2.7. Obtaining the installation program
Before you install OpenShift Container Platform, download the installation file on the host you are using for installation.
Prerequisites
- You have a computer that runs Linux or macOS, with 500 MB of local disk space.
Procedure
- Access the Infrastructure Provider page on the OpenShift Cluster Manager site. If you have a Red Hat account, log in with your credentials. If you do not, create an account.
- Select your infrastructure provider.
Navigate to the page for your installation type, download the installation program that corresponds with your host operating system and architecture, and place the file in the directory where you will store the installation configuration files.
ImportantThe installation program creates several files on the computer that you use to install your cluster. You must keep the installation program and the files that the installation program creates after you finish installing the cluster. Both files are required to delete the cluster.
ImportantDeleting the files created by the installation program does not remove your cluster, even if the cluster failed during installation. To remove your cluster, complete the OpenShift Container Platform uninstallation procedures for your specific cloud provider.
Extract the installation program. For example, on a computer that uses a Linux operating system, run the following command:
$ tar -xvf openshift-install-linux.tar.gz
- Download your installation pull secret from the Red Hat OpenShift Cluster Manager. This pull secret allows you to authenticate with the services that are provided by the included authorities, including Quay.io, which serves the container images for OpenShift Container Platform components.
2.8. Installing the OpenShift CLI by downloading the binary
You can install the OpenShift CLI (oc
) to interact with OpenShift Container Platform from a command-line interface. You can install oc
on Linux, Windows, or macOS.
If you installed an earlier version of oc
, you cannot use it to complete all of the commands in OpenShift Container Platform 4.13. Download and install the new version of oc
.
Installing the OpenShift CLI on Linux
You can install the OpenShift CLI (oc
) binary on Linux by using the following procedure.
Procedure
- Navigate to the OpenShift Container Platform downloads page on the Red Hat Customer Portal.
- Select the architecture from the Product Variant drop-down list.
- Select the appropriate version from the Version drop-down list.
- Click Download Now next to the OpenShift v4.13 Linux Client entry and save the file.
Unpack the archive:
$ tar xvf <file>
Place the
oc
binary in a directory that is on yourPATH
.To check your
PATH
, execute the following command:$ echo $PATH
Verification
After you install the OpenShift CLI, it is available using the
oc
command:$ oc <command>
Installing the OpenShift CLI on Windows
You can install the OpenShift CLI (oc
) binary on Windows by using the following procedure.
Procedure
- Navigate to the OpenShift Container Platform downloads page on the Red Hat Customer Portal.
- Select the appropriate version from the Version drop-down list.
- Click Download Now next to the OpenShift v4.13 Windows Client entry and save the file.
- Unzip the archive with a ZIP program.
Move the
oc
binary to a directory that is on yourPATH
.To check your
PATH
, open the command prompt and execute the following command:C:\> path
Verification
After you install the OpenShift CLI, it is available using the
oc
command:C:\> oc <command>
Installing the OpenShift CLI on macOS
You can install the OpenShift CLI (oc
) binary on macOS by using the following procedure.
Procedure
- Navigate to the OpenShift Container Platform downloads page on the Red Hat Customer Portal.
- Select the appropriate version from the Version drop-down list.
Click Download Now next to the OpenShift v4.13 macOS Client entry and save the file.
NoteFor macOS arm64, choose the OpenShift v4.13 macOS arm64 Client entry.
- Unpack and unzip the archive.
Move the
oc
binary to a directory on your PATH.To check your
PATH
, open a terminal and execute the following command:$ echo $PATH
Verification
After you install the OpenShift CLI, it is available using the
oc
command:$ oc <command>
2.9. Manually creating the installation configuration file
Installing the cluster requires that you manually create the installation configuration file.
Prerequisites
- You have an SSH public key on your local machine to provide to the installation program. The key will be used for SSH authentication onto your cluster nodes for debugging and disaster recovery.
- You have obtained the OpenShift Container Platform installation program and the pull secret for your cluster.
Procedure
Create an installation directory to store your required installation assets in:
$ mkdir <installation_directory>
ImportantYou must create a directory. Some installation assets, like bootstrap X.509 certificates have short expiration intervals, so you must not reuse an installation directory. If you want to reuse individual files from another cluster installation, you can copy them into your directory. However, the file names for the installation assets might change between releases. Use caution when copying installation files from an earlier OpenShift Container Platform version.
Customize the sample
install-config.yaml
file template that is provided and save it in the<installation_directory>
.NoteYou must name this configuration file
install-config.yaml
.Back up the
install-config.yaml
file so that you can use it to install multiple clusters.ImportantThe
install-config.yaml
file is consumed during the next step of the installation process. You must back it up now.
2.9.1. Installation configuration parameters
Before you deploy an OpenShift Container Platform cluster, you provide a customized install-config.yaml
installation configuration file that describes the details for your environment.
After installation, you cannot modify these parameters in the install-config.yaml
file.
2.9.1.1. Required configuration parameters
Required installation configuration parameters are described in the following table:
Parameter | Description | Values |
---|---|---|
|
The API version for the | String |
|
The base domain of your cloud provider. The base domain is used to create routes to your OpenShift Container Platform cluster components. The full DNS name for your cluster is a combination of the |
A fully-qualified domain or subdomain name, such as |
|
Kubernetes resource | Object |
|
The name of the cluster. DNS records for the cluster are all subdomains of |
String of lowercase letters and hyphens ( |
|
The configuration for the specific platform upon which to perform the installation: | Object |
| Get a pull secret from the Red Hat OpenShift Cluster Manager to authenticate downloading container images for OpenShift Container Platform components from services such as Quay.io. |
{ "auths":{ "cloud.openshift.com":{ "auth":"b3Blb=", "email":"you@example.com" }, "quay.io":{ "auth":"b3Blb=", "email":"you@example.com" } } } |
2.9.1.2. Network configuration parameters
You can customize your installation configuration based on the requirements of your existing network infrastructure. For example, you can expand the IP address block for the cluster network or provide different IP address blocks than the defaults.
- If you use the Red Hat OpenShift Networking OVN-Kubernetes network plugin, both IPv4 and IPv6 address families are supported.
- If you use the Red Hat OpenShift Networking OpenShift SDN network plugin, only the IPv4 address family is supported.
If you configure your cluster to use both IP address families, review the following requirements:
- Both IP families must use the same network interface for the default gateway.
- Both IP families must have the default gateway.
- You must specify IPv4 and IPv6 addresses in the same order for all network configuration parameters. For example, in the following configuration IPv4 addresses are listed before IPv6 addresses.
networking: clusterNetwork: - cidr: 10.128.0.0/14 hostPrefix: 23 - cidr: fd00:10:128::/56 hostPrefix: 64 serviceNetwork: - 172.30.0.0/16 - fd00:172:16::/112
Globalnet is not supported with Red Hat OpenShift Data Foundation disaster recovery solutions. For regional disaster recovery scenarios, ensure that you use a nonoverlapping range of private IP addresses for the cluster and service networks in each cluster.
Parameter | Description | Values |
---|---|---|
| The configuration for the cluster network. | Object Note
You cannot modify parameters specified by the |
| The Red Hat OpenShift Networking network plugin to install. |
Either |
| The IP address blocks for pods.
The default value is If you specify multiple IP address blocks, the blocks must not overlap. | An array of objects. For example: networking: clusterNetwork: - cidr: 10.128.0.0/14 hostPrefix: 23 - cidr: fd01::/48 hostPrefix: 64 |
|
Required if you use If you use the OpenShift SDN network plugin, specify an IPv4 network. If you use the OVN-Kubernetes network plugin, you can specify IPv4 and IPv6 networks. |
An IP address block in Classless Inter-Domain Routing (CIDR) notation. The prefix length for an IPv4 block is between |
|
The subnet prefix length to assign to each individual node. For example, if | A subnet prefix.
For an IPv4 network the default value is |
|
The IP address block for services. The default value is The OpenShift SDN and OVN-Kubernetes network plugins support only a single IP address block for the service network. If you use the OVN-Kubernetes network plugin, you can specify an IP address block for both of the IPv4 and IPv6 address families. | An array with an IP address block in CIDR format. For example: networking: serviceNetwork: - 172.30.0.0/16 - fd02::/112 |
| The IP address blocks for machines. If you specify multiple IP address blocks, the blocks must not overlap. | An array of objects. For example: networking: machineNetwork: - cidr: 10.0.0.0/16 |
|
Required if you use | An IP network block in CIDR notation.
For example, Note
Set the |
2.9.1.3. Optional configuration parameters
Optional installation configuration parameters are described in the following table:
Parameter | Description | Values |
---|---|---|
| A PEM-encoded X.509 certificate bundle that is added to the nodes' trusted certificate store. This trust bundle may also be used when a proxy has been configured. | String |
| Controls the installation of optional core cluster components. You can reduce the footprint of your OpenShift Container Platform cluster by disabling optional components. For more information, see the "Cluster capabilities" page in Installing. | String array |
|
Selects an initial set of optional capabilities to enable. Valid values are | String |
|
Extends the set of optional capabilities beyond what you specify in | String array |
| Enables workload partitioning, which isolates OpenShift Container Platform services, cluster management workloads, and infrastructure pods to run on a reserved set of CPUs. Workload partitioning can only be enabled during installation and cannot be disabled after installation. While this field enables workload partitioning, it does not configure workloads to use specific CPUs. For more information, see the Workload partitioning page in the Scalability and Performance section. |
|
| The configuration for the machines that comprise the compute nodes. |
Array of |
|
Determines the instruction set architecture of the machines in the pool. Currently, clusters with varied architectures are not supported. All pools must specify the same architecture. Valid values are | String |
compute: hyperthreading: |
Whether to enable or disable simultaneous multithreading, or Important If you disable simultaneous multithreading, ensure that your capacity planning accounts for the dramatically decreased machine performance. |
|
|
Required if you use |
|
|
Required if you use |
|
| The number of compute machines, which are also known as worker machines, to provision. |
A positive integer greater than or equal to |
| Enables the cluster for a feature set. A feature set is a collection of OpenShift Container Platform features that are not enabled by default. For more information about enabling a feature set during installation, see "Enabling features using feature gates". |
String. The name of the feature set to enable, such as |
| The configuration for the machines that comprise the control plane. |
Array of |
|
Determines the instruction set architecture of the machines in the pool. Currently, clusters with varied architectures are not supported. All pools must specify the same architecture. Valid values are | String |
controlPlane: hyperthreading: |
Whether to enable or disable simultaneous multithreading, or Important If you disable simultaneous multithreading, ensure that your capacity planning accounts for the dramatically decreased machine performance. |
|
|
Required if you use |
|
|
Required if you use |
|
| The number of control plane machines to provision. |
The only supported value is |
| The Cloud Credential Operator (CCO) mode. If no mode is specified, the CCO dynamically tries to determine the capabilities of the provided credentials, with a preference for mint mode on the platforms where multiple modes are supported. Note Not all CCO modes are supported for all cloud providers. For more information about CCO modes, see the Cloud Credential Operator entry in the Cluster Operators reference content. Note
If your AWS account has service control policies (SCP) enabled, you must configure the |
|
| Sources and repositories for the release-image content. |
Array of objects. Includes a |
|
Required if you use | String |
| Specify one or more repositories that may also contain the same images. | Array of strings |
| How to publish or expose the user-facing endpoints of your cluster, such as the Kubernetes API, OpenShift routes. |
Setting this field to Important
If the value of the field is set to |
| The SSH key to authenticate access to your cluster machines. Note
For production OpenShift Container Platform clusters on which you want to perform installation debugging or disaster recovery, specify an SSH key that your |
For example, |
- Not all CCO modes are supported for all cloud providers. For more information about CCO modes, see the "Managing cloud provider credentials" entry in the Authentication and authorization content.
2.9.2. Sample install-config.yaml file for bare metal
You can customize the install-config.yaml
file to specify more details about your OpenShift Container Platform cluster’s platform or modify the values of the required parameters.
apiVersion: v1 baseDomain: example.com 1 compute: 2 - hyperthreading: Enabled 3 name: worker replicas: 0 4 controlPlane: 5 hyperthreading: Enabled 6 name: master replicas: 3 7 metadata: name: test 8 networking: clusterNetwork: - cidr: 10.128.0.0/14 9 hostPrefix: 23 10 networkType: OVNKubernetes 11 serviceNetwork: 12 - 172.30.0.0/16 platform: none: {} 13 fips: false 14 pullSecret: '{"auths": ...}' 15 sshKey: 'ssh-ed25519 AAAA...' 16
- 1
- The base domain of the cluster. All DNS records must be sub-domains of this base and include the cluster name.
- 2 5
- The
controlPlane
section is a single mapping, but thecompute
section is a sequence of mappings. To meet the requirements of the different data structures, the first line of thecompute
section must begin with a hyphen,-
, and the first line of thecontrolPlane
section must not. Only one control plane pool is used. - 3 6
- Specifies whether to enable or disable simultaneous multithreading (SMT), or hyperthreading. By default, SMT is enabled to increase the performance of the cores in your machines. You can disable it by setting the parameter value to
Disabled
. If you disable SMT, you must disable it in all cluster machines; this includes both control plane and compute machines.NoteSimultaneous multithreading (SMT) is enabled by default. If SMT is not enabled in your BIOS settings, the
hyperthreading
parameter has no effect.ImportantIf you disable
hyperthreading
, whether in the BIOS or in theinstall-config.yaml
file, ensure that your capacity planning accounts for the dramatically decreased machine performance. - 4
- You must set this value to
0
when you install OpenShift Container Platform on user-provisioned infrastructure. In installer-provisioned installations, the parameter controls the number of compute machines that the cluster creates and manages for you. In user-provisioned installations, you must manually deploy the compute machines before you finish installing the cluster.NoteIf you are installing a three-node cluster, do not deploy any compute machines when you install the Red Hat Enterprise Linux CoreOS (RHCOS) machines.
- 7
- The number of control plane machines that you add to the cluster. Because the cluster uses these values as the number of etcd endpoints in the cluster, the value must match the number of control plane machines that you deploy.
- 8
- The cluster name that you specified in your DNS records.
- 9
- A block of IP addresses from which pod IP addresses are allocated. This block must not overlap with existing physical networks. These IP addresses are used for the pod network. If you need to access the pods from an external network, you must configure load balancers and routers to manage the traffic.Note
Class E CIDR range is reserved for a future use. To use the Class E CIDR range, you must ensure your networking environment accepts the IP addresses within the Class E CIDR range.
- 10
- The subnet prefix length to assign to each individual node. For example, if
hostPrefix
is set to23
, then each node is assigned a/23
subnet out of the givencidr
, which allows for 510 (2^(32 - 23) - 2) pod IP addresses. If you are required to provide access to nodes from an external network, configure load balancers and routers to manage the traffic. - 11
- The cluster network plugin to install. The supported values are
OVNKubernetes
andOpenShiftSDN
. The default value isOVNKubernetes
. - 12
- The IP address pool to use for service IP addresses. You can enter only one IP address pool. This block must not overlap with existing physical networks. If you need to access the services from an external network, configure load balancers and routers to manage the traffic.
- 13
- You must set the platform to
none
. You cannot provide additional platform configuration variables for your platform.ImportantClusters that are installed with the platform type
none
are unable to use some features, such as managing compute machines with the Machine API. This limitation applies even if the compute machines that are attached to the cluster are installed on a platform that would normally support the feature. This parameter cannot be changed after installation. - 14
- Whether to enable or disable FIPS mode. By default, FIPS mode is not enabled.Important
OpenShift Container Platform 4.13 is based on Red Hat Enterprise Linux (RHEL) 9.2. RHEL 9.2 cryptographic modules have not yet been submitted for FIPS validation. For more information, see "About this release" in the 4.13 OpenShift Container Platform Release Notes.
- 15
- The pull secret from the Red Hat OpenShift Cluster Manager. This pull secret allows you to authenticate with the services that are provided by the included authorities, including Quay.io, which serves the container images for OpenShift Container Platform components.
- 16
- The SSH public key for the
core
user in Red Hat Enterprise Linux CoreOS (RHCOS).NoteFor production OpenShift Container Platform clusters on which you want to perform installation debugging or disaster recovery, specify an SSH key that your
ssh-agent
process uses.
Additional resources
- See Load balancing requirements for user-provisioned infrastructure for more information on the API and application ingress load balancing requirements.
- See Enabling cluster capabilities for more information on enabling cluster capabilities that were disabled prior to installation.
- See Optional cluster capabilities in OpenShift Container Platform 4.13 for more information about the features provided by each capability.
2.9.3. Configuring the cluster-wide proxy during installation
Production environments can deny direct access to the internet and instead have an HTTP or HTTPS proxy available. You can configure a new OpenShift Container Platform cluster to use a proxy by configuring the proxy settings in the install-config.yaml
file.
For bare metal installations, if you do not assign node IP addresses from the range that is specified in the networking.machineNetwork[].cidr
field in the install-config.yaml
file, you must include them in the proxy.noProxy
field.
Prerequisites
-
You have an existing
install-config.yaml
file. You reviewed the sites that your cluster requires access to and determined whether any of them need to bypass the proxy. By default, all cluster egress traffic is proxied, including calls to hosting cloud provider APIs. You added sites to the
Proxy
object’sspec.noProxy
field to bypass the proxy if necessary.NoteThe
Proxy
objectstatus.noProxy
field is populated with the values of thenetworking.machineNetwork[].cidr
,networking.clusterNetwork[].cidr
, andnetworking.serviceNetwork[]
fields from your installation configuration.For installations on Amazon Web Services (AWS), Google Cloud Platform (GCP), Microsoft Azure, and Red Hat OpenStack Platform (RHOSP), the
Proxy
objectstatus.noProxy
field is also populated with the instance metadata endpoint (169.254.169.254
).
Procedure
Edit your
install-config.yaml
file and add the proxy settings. For example:apiVersion: v1 baseDomain: my.domain.com proxy: httpProxy: http://<username>:<pswd>@<ip>:<port> 1 httpsProxy: https://<username>:<pswd>@<ip>:<port> 2 noProxy: example.com 3 additionalTrustBundle: | 4 -----BEGIN CERTIFICATE----- <MY_TRUSTED_CA_CERT> -----END CERTIFICATE----- additionalTrustBundlePolicy: <policy_to_add_additionalTrustBundle> 5
- 1
- A proxy URL to use for creating HTTP connections outside the cluster. The URL scheme must be
http
. - 2
- A proxy URL to use for creating HTTPS connections outside the cluster.
- 3
- A comma-separated list of destination domain names, IP addresses, or other network CIDRs to exclude from proxying. Preface a domain with
.
to match subdomains only. For example,.y.com
matchesx.y.com
, but noty.com
. Use*
to bypass the proxy for all destinations. - 4
- If provided, the installation program generates a config map that is named
user-ca-bundle
in theopenshift-config
namespace that contains one or more additional CA certificates that are required for proxying HTTPS connections. The Cluster Network Operator then creates atrusted-ca-bundle
config map that merges these contents with the Red Hat Enterprise Linux CoreOS (RHCOS) trust bundle, and this config map is referenced in thetrustedCA
field of theProxy
object. TheadditionalTrustBundle
field is required unless the proxy’s identity certificate is signed by an authority from the RHCOS trust bundle. - 5
- Optional: The policy to determine the configuration of the
Proxy
object to reference theuser-ca-bundle
config map in thetrustedCA
field. The allowed values areProxyonly
andAlways
. UseProxyonly
to reference theuser-ca-bundle
config map only whenhttp/https
proxy is configured. UseAlways
to always reference theuser-ca-bundle
config map. The default value isProxyonly
.
NoteThe installation program does not support the proxy
readinessEndpoints
field.NoteIf the installer times out, restart and then complete the deployment by using the
wait-for
command of the installer. For example:$ ./openshift-install wait-for install-complete --log-level debug
- Save the file and reference it when installing OpenShift Container Platform.
The installation program creates a cluster-wide proxy that is named cluster
that uses the proxy settings in the provided install-config.yaml
file. If no proxy settings are provided, a cluster
Proxy
object is still created, but it will have a nil spec
.
Only the Proxy
object named cluster
is supported, and no additional proxies can be created.
2.9.4. Configuring a three-node cluster
Optionally, you can deploy zero compute machines in a bare metal cluster that consists of three control plane machines only. This provides smaller, more resource efficient clusters for cluster administrators and developers to use for testing, development, and production.
In three-node OpenShift Container Platform environments, the three control plane machines are schedulable, which means that your application workloads are scheduled to run on them.
Prerequisites
-
You have an existing
install-config.yaml
file.
Procedure
Ensure that the number of compute replicas is set to
0
in yourinstall-config.yaml
file, as shown in the followingcompute
stanza:compute: - name: worker platform: {} replicas: 0
NoteYou must set the value of the
replicas
parameter for the compute machines to0
when you install OpenShift Container Platform on user-provisioned infrastructure, regardless of the number of compute machines you are deploying. In installer-provisioned installations, the parameter controls the number of compute machines that the cluster creates and manages for you. This does not apply to user-provisioned installations, where the compute machines are deployed manually.
For three-node cluster installations, follow these next steps:
- If you are deploying a three-node cluster with zero compute nodes, the Ingress Controller pods run on the control plane nodes. In three-node cluster deployments, you must configure your application ingress load balancer to route HTTP and HTTPS traffic to the control plane nodes. See the Load balancing requirements for user-provisioned infrastructure section for more information.
-
When you create the Kubernetes manifest files in the following procedure, ensure that the
mastersSchedulable
parameter in the<installation_directory>/manifests/cluster-scheduler-02-config.yml
file is set totrue
. This enables your application workloads to run on the control plane nodes. - Do not deploy any compute nodes when you create the Red Hat Enterprise Linux CoreOS (RHCOS) machines.
2.10. Creating the Kubernetes manifest and Ignition config files
Because you must modify some cluster definition files and manually start the cluster machines, you must generate the Kubernetes manifest and Ignition config files that the cluster needs to configure the machines.
The installation configuration file transforms into the Kubernetes manifests. The manifests wrap into the Ignition configuration files, which are later used to configure the cluster machines.
-
The Ignition config files that the OpenShift Container Platform installation program generates contain certificates that expire after 24 hours, which are then renewed at that time. If the cluster is shut down before renewing the certificates and the cluster is later restarted after the 24 hours have elapsed, the cluster automatically recovers the expired certificates. The exception is that you must manually approve the pending
node-bootstrapper
certificate signing requests (CSRs) to recover kubelet certificates. See the documentation for Recovering from expired control plane certificates for more information. - It is recommended that you use Ignition config files within 12 hours after they are generated because the 24-hour certificate rotates from 16 to 22 hours after the cluster is installed. By using the Ignition config files within 12 hours, you can avoid installation failure if the certificate update runs during installation.
Prerequisites
- You obtained the OpenShift Container Platform installation program.
-
You created the
install-config.yaml
installation configuration file.
Procedure
Change to the directory that contains the OpenShift Container Platform installation program and generate the Kubernetes manifests for the cluster:
$ ./openshift-install create manifests --dir <installation_directory> 1
- 1
- For
<installation_directory>
, specify the installation directory that contains theinstall-config.yaml
file you created.
WarningIf you are installing a three-node cluster, skip the following step to allow the control plane nodes to be schedulable.
ImportantWhen you configure control plane nodes from the default unschedulable to schedulable, additional subscriptions are required. This is because control plane nodes then become compute nodes.
Check that the
mastersSchedulable
parameter in the<installation_directory>/manifests/cluster-scheduler-02-config.yml
Kubernetes manifest file is set tofalse
. This setting prevents pods from being scheduled on the control plane machines:-
Open the
<installation_directory>/manifests/cluster-scheduler-02-config.yml
file. -
Locate the
mastersSchedulable
parameter and ensure that it is set tofalse
. - Save and exit the file.
-
Open the
To create the Ignition configuration files, run the following command from the directory that contains the installation program:
$ ./openshift-install create ignition-configs --dir <installation_directory> 1
- 1
- For
<installation_directory>
, specify the same installation directory.
Ignition config files are created for the bootstrap, control plane, and compute nodes in the installation directory. The
kubeadmin-password
andkubeconfig
files are created in the./<installation_directory>/auth
directory:. ├── auth │ ├── kubeadmin-password │ └── kubeconfig ├── bootstrap.ign ├── master.ign ├── metadata.json └── worker.ign
Additional resources
- See Recovering from expired control plane certificates for more information about recovering kubelet certificates.
2.11. Installing RHCOS and starting the OpenShift Container Platform bootstrap process
To install OpenShift Container Platform on bare metal infrastructure that you provision, you must install Red Hat Enterprise Linux CoreOS (RHCOS) on the machines. When you install RHCOS, you must provide the Ignition config file that was generated by the OpenShift Container Platform installation program for the type of machine you are installing. If you have configured suitable networking, DNS, and load balancing infrastructure, the OpenShift Container Platform bootstrap process begins automatically after the RHCOS machines have rebooted.
To install RHCOS on the machines, follow either the steps to use an ISO image or network PXE booting.
The compute node deployment steps included in this installation document are RHCOS-specific. If you choose instead to deploy RHEL-based compute nodes, you take responsibility for all operating system life cycle management and maintenance, including performing system updates, applying patches, and completing all other required tasks. Only RHEL 8 compute machines are supported.
You can configure RHCOS during ISO and PXE installations by using the following methods:
-
Kernel arguments: You can use kernel arguments to provide installation-specific information. For example, you can specify the locations of the RHCOS installation files that you uploaded to your HTTP server and the location of the Ignition config file for the type of node you are installing. For a PXE installation, you can use the
APPEND
parameter to pass the arguments to the kernel of the live installer. For an ISO installation, you can interrupt the live installation boot process to add the kernel arguments. In both installation cases, you can use specialcoreos.inst.*
arguments to direct the live installer, as well as standard installation boot arguments for turning standard kernel services on or off. -
Ignition configs: OpenShift Container Platform Ignition config files (
*.ign
) are specific to the type of node you are installing. You pass the location of a bootstrap, control plane, or compute node Ignition config file during the RHCOS installation so that it takes effect on first boot. In special cases, you can create a separate, limited Ignition config to pass to the live system. That Ignition config could do a certain set of tasks, such as reporting success to a provisioning system after completing installation. This special Ignition config is consumed by thecoreos-installer
to be applied on first boot of the installed system. Do not provide the standard control plane and compute node Ignition configs to the live ISO directly. -
coreos-installer
: You can boot the live ISO installer to a shell prompt, which allows you to prepare the permanent system in a variety of ways before first boot. In particular, you can run thecoreos-installer
command to identify various artifacts to include, work with disk partitions, and set up networking. In some cases, you can configure features on the live system and copy them to the installed system.
Whether to use an ISO or PXE install depends on your situation. A PXE install requires an available DHCP service and more preparation, but can make the installation process more automated. An ISO install is a more manual process and can be inconvenient if you are setting up more than a few machines.
As of OpenShift Container Platform 4.6, the RHCOS ISO and other installation artifacts provide support for installation on disks with 4K sectors.
2.11.1. Installing RHCOS by using an ISO image
You can use an ISO image to install RHCOS on the machines.
Prerequisites
- You have created the Ignition config files for your cluster.
- You have configured suitable network, DNS and load balancing infrastructure.
- You have an HTTP server that can be accessed from your computer, and from the machines that you create.
- You have reviewed the Advanced RHCOS installation configuration section for different ways to configure features, such as networking and disk partitioning.
Procedure
Obtain the SHA512 digest for each of your Ignition config files. For example, you can use the following on a system running Linux to get the SHA512 digest for your
bootstrap.ign
Ignition config file:$ sha512sum <installation_directory>/bootstrap.ign
The digests are provided to the
coreos-installer
in a later step to validate the authenticity of the Ignition config files on the cluster nodes.Upload the bootstrap, control plane, and compute node Ignition config files that the installation program created to your HTTP server. Note the URLs of these files.
ImportantYou can add or change configuration settings in your Ignition configs before saving them to your HTTP server. If you plan to add more compute machines to your cluster after you finish installation, do not delete these files.
From the installation host, validate that the Ignition config files are available on the URLs. The following example gets the Ignition config file for the bootstrap node:
$ curl -k http://<HTTP_server>/bootstrap.ign 1
Example output
% Total % Received % Xferd Average Speed Time Time Time Current Dload Upload Total Spent Left Speed 0 0 0 0 0 0 0 0 --:--:-- --:--:-- --:--:-- 0{"ignition":{"version":"3.2.0"},"passwd":{"users":[{"name":"core","sshAuthorizedKeys":["ssh-rsa...
Replace
bootstrap.ign
withmaster.ign
orworker.ign
in the command to validate that the Ignition config files for the control plane and compute nodes are also available.Although it is possible to obtain the RHCOS images that are required for your preferred method of installing operating system instances from the RHCOS image mirror page, the recommended way to obtain the correct version of your RHCOS images are from the output of
openshift-install
command:$ openshift-install coreos print-stream-json | grep '\.iso[^.]'
Example output
"location": "<url>/art/storage/releases/rhcos-4.13-aarch64/<release>/aarch64/rhcos-<release>-live.aarch64.iso", "location": "<url>/art/storage/releases/rhcos-4.13-ppc64le/<release>/ppc64le/rhcos-<release>-live.ppc64le.iso", "location": "<url>/art/storage/releases/rhcos-4.13-s390x/<release>/s390x/rhcos-<release>-live.s390x.iso", "location": "<url>/art/storage/releases/rhcos-4.13/<release>/x86_64/rhcos-<release>-live.x86_64.iso",
ImportantThe RHCOS images might not change with every release of OpenShift Container Platform. You must download images with the highest version that is less than or equal to the OpenShift Container Platform version that you install. Use the image versions that match your OpenShift Container Platform version if they are available. Use only ISO images for this procedure. RHCOS qcow2 images are not supported for this installation type.
ISO file names resemble the following example:
rhcos-<version>-live.<architecture>.iso
Use the ISO to start the RHCOS installation. Use one of the following installation options:
- Burn the ISO image to a disk and boot it directly.
- Use ISO redirection by using a lights-out management (LOM) interface.
Boot the RHCOS ISO image without specifying any options or interrupting the live boot sequence. Wait for the installer to boot into a shell prompt in the RHCOS live environment.
NoteIt is possible to interrupt the RHCOS installation boot process to add kernel arguments. However, for this ISO procedure you should use the
coreos-installer
command as outlined in the following steps, instead of adding kernel arguments.Run the
coreos-installer
command and specify the options that meet your installation requirements. At a minimum, you must specify the URL that points to the Ignition config file for the node type, and the device that you are installing to:$ sudo coreos-installer install --ignition-url=http://<HTTP_server>/<node_type>.ign <device> --ignition-hash=sha512-<digest> 12
- 1 1
- You must run the
coreos-installer
command by usingsudo
, because thecore
user does not have the required root privileges to perform the installation. - 2
- The
--ignition-hash
option is required when the Ignition config file is obtained through an HTTP URL to validate the authenticity of the Ignition config file on the cluster node.<digest>
is the Ignition config file SHA512 digest obtained in a preceding step.
NoteIf you want to provide your Ignition config files through an HTTPS server that uses TLS, you can add the internal certificate authority (CA) to the system trust store before running
coreos-installer
.The following example initializes a bootstrap node installation to the
/dev/sda
device. The Ignition config file for the bootstrap node is obtained from an HTTP web server with the IP address 192.168.1.2:$ sudo coreos-installer install --ignition-url=http://192.168.1.2:80/installation_directory/bootstrap.ign /dev/sda --ignition-hash=sha512-a5a2d43879223273c9b60af66b44202a1d1248fc01cf156c46d4a79f552b6bad47bc8cc78ddf0116e80c59d2ea9e32ba53bc807afbca581aa059311def2c3e3b
Monitor the progress of the RHCOS installation on the console of the machine.
ImportantBe sure that the installation is successful on each node before commencing with the OpenShift Container Platform installation. Observing the installation process can also help to determine the cause of RHCOS installation issues that might arise.
- After RHCOS installs, you must reboot the system. During the system reboot, it applies the Ignition config file that you specified.
Check the console output to verify that Ignition ran.
Example command
Ignition: ran on 2022/03/14 14:48:33 UTC (this boot) Ignition: user-provided config was applied
Continue to create the other machines for your cluster.
ImportantYou must create the bootstrap and control plane machines at this time. If the control plane machines are not made schedulable, also create at least two compute machines before you install OpenShift Container Platform.
If the required network, DNS, and load balancer infrastructure are in place, the OpenShift Container Platform bootstrap process begins automatically after the RHCOS nodes have rebooted.
NoteRHCOS nodes do not include a default password for the
core
user. You can access the nodes by runningssh core@<node>.<cluster_name>.<base_domain>
as a user with access to the SSH private key that is paired to the public key that you specified in yourinstall_config.yaml
file. OpenShift Container Platform 4 cluster nodes running RHCOS are immutable and rely on Operators to apply cluster changes. Accessing cluster nodes by using SSH is not recommended. However, when investigating installation issues, if the OpenShift Container Platform API is not available, or the kubelet is not properly functioning on a target node, SSH access might be required for debugging or disaster recovery.
2.11.2. Installing RHCOS by using PXE or iPXE booting
You can use PXE or iPXE booting to install RHCOS on the machines.
Prerequisites
- You have created the Ignition config files for your cluster.
- You have configured suitable network, DNS and load balancing infrastructure.
- You have configured suitable PXE or iPXE infrastructure.
- You have an HTTP server that can be accessed from your computer, and from the machines that you create.
- You have reviewed the Advanced RHCOS installation configuration section for different ways to configure features, such as networking and disk partitioning.
Procedure
Upload the bootstrap, control plane, and compute node Ignition config files that the installation program created to your HTTP server. Note the URLs of these files.
ImportantYou can add or change configuration settings in your Ignition configs before saving them to your HTTP server. If you plan to add more compute machines to your cluster after you finish installation, do not delete these files.
From the installation host, validate that the Ignition config files are available on the URLs. The following example gets the Ignition config file for the bootstrap node:
$ curl -k http://<HTTP_server>/bootstrap.ign 1
Example output
% Total % Received % Xferd Average Speed Time Time Time Current Dload Upload Total Spent Left Speed 0 0 0 0 0 0 0 0 --:--:-- --:--:-- --:--:-- 0{"ignition":{"version":"3.2.0"},"passwd":{"users":[{"name":"core","sshAuthorizedKeys":["ssh-rsa...
Replace
bootstrap.ign
withmaster.ign
orworker.ign
in the command to validate that the Ignition config files for the control plane and compute nodes are also available.Although it is possible to obtain the RHCOS
kernel
,initramfs
androotfs
files that are required for your preferred method of installing operating system instances from the RHCOS image mirror page, the recommended way to obtain the correct version of your RHCOS files are from the output ofopenshift-install
command:$ openshift-install coreos print-stream-json | grep -Eo '"https.*(kernel-|initramfs.|rootfs.)\w+(\.img)?"'
Example output
"<url>/art/storage/releases/rhcos-4.13-aarch64/<release>/aarch64/rhcos-<release>-live-kernel-aarch64" "<url>/art/storage/releases/rhcos-4.13-aarch64/<release>/aarch64/rhcos-<release>-live-initramfs.aarch64.img" "<url>/art/storage/releases/rhcos-4.13-aarch64/<release>/aarch64/rhcos-<release>-live-rootfs.aarch64.img" "<url>/art/storage/releases/rhcos-4.13-ppc64le/49.84.202110081256-0/ppc64le/rhcos-<release>-live-kernel-ppc64le" "<url>/art/storage/releases/rhcos-4.13-ppc64le/<release>/ppc64le/rhcos-<release>-live-initramfs.ppc64le.img" "<url>/art/storage/releases/rhcos-4.13-ppc64le/<release>/ppc64le/rhcos-<release>-live-rootfs.ppc64le.img" "<url>/art/storage/releases/rhcos-4.13-s390x/<release>/s390x/rhcos-<release>-live-kernel-s390x" "<url>/art/storage/releases/rhcos-4.13-s390x/<release>/s390x/rhcos-<release>-live-initramfs.s390x.img" "<url>/art/storage/releases/rhcos-4.13-s390x/<release>/s390x/rhcos-<release>-live-rootfs.s390x.img" "<url>/art/storage/releases/rhcos-4.13/<release>/x86_64/rhcos-<release>-live-kernel-x86_64" "<url>/art/storage/releases/rhcos-4.13/<release>/x86_64/rhcos-<release>-live-initramfs.x86_64.img" "<url>/art/storage/releases/rhcos-4.13/<release>/x86_64/rhcos-<release>-live-rootfs.x86_64.img"
ImportantThe RHCOS artifacts might not change with every release of OpenShift Container Platform. You must download images with the highest version that is less than or equal to the OpenShift Container Platform version that you install. Only use the appropriate
kernel
,initramfs
, androotfs
artifacts described below for this procedure. RHCOS QCOW2 images are not supported for this installation type.The file names contain the OpenShift Container Platform version number. They resemble the following examples:
-
kernel
:rhcos-<version>-live-kernel-<architecture>
-
initramfs
:rhcos-<version>-live-initramfs.<architecture>.img
-
rootfs
:rhcos-<version>-live-rootfs.<architecture>.img
-
Upload the
rootfs
,kernel
, andinitramfs
files to your HTTP server.ImportantIf you plan to add more compute machines to your cluster after you finish installation, do not delete these files.
- Configure the network boot infrastructure so that the machines boot from their local disks after RHCOS is installed on them.
Configure PXE or iPXE installation for the RHCOS images and begin the installation.
Modify one of the following example menu entries for your environment and verify that the image and Ignition files are properly accessible:
For PXE (
x86_64
):DEFAULT pxeboot TIMEOUT 20 PROMPT 0 LABEL pxeboot KERNEL http://<HTTP_server>/rhcos-<version>-live-kernel-<architecture> 1 APPEND initrd=http://<HTTP_server>/rhcos-<version>-live-initramfs.<architecture>.img coreos.live.rootfs_url=http://<HTTP_server>/rhcos-<version>-live-rootfs.<architecture>.img coreos.inst.install_dev=/dev/sda coreos.inst.ignition_url=http://<HTTP_server>/bootstrap.ign 2 3
- 1 1
- Specify the location of the live
kernel
file that you uploaded to your HTTP server. The URL must be HTTP, TFTP, or FTP; HTTPS and NFS are not supported. - 2
- If you use multiple NICs, specify a single interface in the
ip
option. For example, to use DHCP on a NIC that is namedeno1
, setip=eno1:dhcp
. - 3
- Specify the locations of the RHCOS files that you uploaded to your HTTP server. The
initrd
parameter value is the location of theinitramfs
file, thecoreos.live.rootfs_url
parameter value is the location of therootfs
file, and thecoreos.inst.ignition_url
parameter value is the location of the bootstrap Ignition config file. You can also add more kernel arguments to theAPPEND
line to configure networking or other boot options.
NoteThis configuration does not enable serial console access on machines with a graphical console. To configure a different console, add one or more
console=
arguments to theAPPEND
line. For example, addconsole=tty0 console=ttyS0
to set the first PC serial port as the primary console and the graphical console as a secondary console. For more information, see How does one set up a serial terminal and/or console in Red Hat Enterprise Linux? and "Enabling the serial console for PXE and ISO installation" in the "Advanced RHCOS installation configuration" section.For iPXE (
x86_64
+aarch64
):kernel http://<HTTP_server>/rhcos-<version>-live-kernel-<architecture> initrd=main coreos.live.rootfs_url=http://<HTTP_server>/rhcos-<version>-live-rootfs.<architecture>.img coreos.inst.install_dev=/dev/sda coreos.inst.ignition_url=http://<HTTP_server>/bootstrap.ign 1 2 initrd --name main http://<HTTP_server>/rhcos-<version>-live-initramfs.<architecture>.img 3 boot
- 1
- Specify the locations of the RHCOS files that you uploaded to your HTTP server. The
kernel
parameter value is the location of thekernel
file, theinitrd=main
argument is needed for booting on UEFI systems, thecoreos.live.rootfs_url
parameter value is the location of therootfs
file, and thecoreos.inst.ignition_url
parameter value is the location of the bootstrap Ignition config file. - 2
- If you use multiple NICs, specify a single interface in the
ip
option. For example, to use DHCP on a NIC that is namedeno1
, setip=eno1:dhcp
. - 3
- Specify the location of the
initramfs
file that you uploaded to your HTTP server.
NoteThis configuration does not enable serial console access on machines with a graphical console. To configure a different console, add one or more
console=
arguments to thekernel
line. For example, addconsole=tty0 console=ttyS0
to set the first PC serial port as the primary console and the graphical console as a secondary console. For more information, see How does one set up a serial terminal and/or console in Red Hat Enterprise Linux? and "Enabling the serial console for PXE and ISO installation" in the "Advanced RHCOS installation configuration" section.NoteTo network boot the CoreOS
kernel
onaarch64
architecture, you need to use a version of iPXE build with theIMAGE_GZIP
option enabled. SeeIMAGE_GZIP
option in iPXE.For PXE (with UEFI and Grub as second stage) on
aarch64
:menuentry 'Install CoreOS' { linux rhcos-<version>-live-kernel-<architecture> coreos.live.rootfs_url=http://<HTTP_server>/rhcos-<version>-live-rootfs.<architecture>.img coreos.inst.install_dev=/dev/sda coreos.inst.ignition_url=http://<HTTP_server>/bootstrap.ign 1 2 initrd rhcos-<version>-live-initramfs.<architecture>.img 3 }
- 1
- Specify the locations of the RHCOS files that you uploaded to your HTTP/TFTP server. The
kernel
parameter value is the location of thekernel
file on your TFTP server. Thecoreos.live.rootfs_url
parameter value is the location of therootfs
file, and thecoreos.inst.ignition_url
parameter value is the location of the bootstrap Ignition config file on your HTTP Server. - 2
- If you use multiple NICs, specify a single interface in the
ip
option. For example, to use DHCP on a NIC that is namedeno1
, setip=eno1:dhcp
. - 3
- Specify the location of the
initramfs
file that you uploaded to your TFTP server.
Monitor the progress of the RHCOS installation on the console of the machine.
ImportantBe sure that the installation is successful on each node before commencing with the OpenShift Container Platform installation. Observing the installation process can also help to determine the cause of RHCOS installation issues that might arise.
- After RHCOS installs, the system reboots. During reboot, the system applies the Ignition config file that you specified.
Check the console output to verify that Ignition ran.
Example command
Ignition: ran on 2022/03/14 14:48:33 UTC (this boot) Ignition: user-provided config was applied
Continue to create the machines for your cluster.
ImportantYou must create the bootstrap and control plane machines at this time. If the control plane machines are not made schedulable, also create at least two compute machines before you install the cluster.
If the required network, DNS, and load balancer infrastructure are in place, the OpenShift Container Platform bootstrap process begins automatically after the RHCOS nodes have rebooted.
NoteRHCOS nodes do not include a default password for the
core
user. You can access the nodes by runningssh core@<node>.<cluster_name>.<base_domain>
as a user with access to the SSH private key that is paired to the public key that you specified in yourinstall_config.yaml
file. OpenShift Container Platform 4 cluster nodes running RHCOS are immutable and rely on Operators to apply cluster changes. Accessing cluster nodes by using SSH is not recommended. However, when investigating installation issues, if the OpenShift Container Platform API is not available, or the kubelet is not properly functioning on a target node, SSH access might be required for debugging or disaster recovery.
2.11.3. Advanced RHCOS installation configuration
A key benefit for manually provisioning the Red Hat Enterprise Linux CoreOS (RHCOS) nodes for OpenShift Container Platform is to be able to do configuration that is not available through default OpenShift Container Platform installation methods. This section describes some of the configurations that you can do using techniques that include:
- Passing kernel arguments to the live installer
-
Running
coreos-installer
manually from the live system - Customizing a live ISO or PXE boot image
The advanced configuration topics for manual Red Hat Enterprise Linux CoreOS (RHCOS) installations detailed in this section relate to disk partitioning, networking, and using Ignition configs in different ways.
2.11.3.1. Using advanced networking options for PXE and ISO installations
Networking for OpenShift Container Platform nodes uses DHCP by default to gather all necessary configuration settings. To set up static IP addresses or configure special settings, such as bonding, you can do one of the following:
- Pass special kernel parameters when you boot the live installer.
- Use a machine config to copy networking files to the installed system.
- Configure networking from a live installer shell prompt, then copy those settings to the installed system so that they take effect when the installed system first boots.
To configure a PXE or iPXE installation, use one of the following options:
- See the "Advanced RHCOS installation reference" tables.
- Use a machine config to copy networking files to the installed system.
To configure an ISO installation, use the following procedure.
Procedure
- Boot the ISO installer.
-
From the live system shell prompt, configure networking for the live system using available RHEL tools, such as
nmcli
ornmtui
. Run the
coreos-installer
command to install the system, adding the--copy-network
option to copy networking configuration. For example:$ sudo coreos-installer install --copy-network \ --ignition-url=http://host/worker.ign /dev/disk/by-id/scsi-<serial_number>
ImportantThe
--copy-network
option only copies networking configuration found under/etc/NetworkManager/system-connections
. In particular, it does not copy the system hostname.- Reboot into the installed system.
Additional resources
-
See Getting started with nmcli and Getting started with nmtui in the RHEL 8 documentation for more information about the
nmcli
andnmtui
tools.
2.11.3.2. Disk partitioning
Disk partitions are created on OpenShift Container Platform cluster nodes during the Red Hat Enterprise Linux CoreOS (RHCOS) installation. Each RHCOS node of a particular architecture uses the same partition layout, unless you override the default partitioning configuration. During the RHCOS installation, the size of the root file system is increased to use any remaining available space on the target device.
The use of a custom partition scheme on your node might result in OpenShift Container Platform not monitoring or alerting on some node partitions. If you override the default partitioning, see Understanding OpenShift File System Monitoring (eviction conditions) for more information about how OpenShift Container Platform monitors your host file systems.
OpenShift Container Platform monitors the following two filesystem identifiers:
-
nodefs
, which is the filesystem that contains/var/lib/kubelet
-
imagefs
, which is the filesystem that contains/var/lib/containers
For the default partition scheme, nodefs
and imagefs
monitor the same root filesystem, /
.
To override the default partitioning when installing RHCOS on an OpenShift Container Platform cluster node, you must create separate partitions.
For disk sizes larger than 100GB, and especially disk sizes larger than 1TB, create a separate /var
partition. See "Creating a separate /var
partition" and this Red Hat Knowledgebase article for more information.
Consider a situation where you want to add a separate storage partition for your containers and container images. For example, by mounting /var/lib/containers
in a separate partition, the kubelet separately monitors /var/lib/containers
as the imagefs
directory and the root file system as the nodefs
directory.
If you have resized your disk size to host a larger file system, consider creating a separate /var/lib/containers
partition. Consider resizing a disk that has an xfs
format to reduce CPU time issues caused by a high number of allocation groups.
2.11.3.2.1. Creating a separate /var
partition
In general, you should use the default disk partitioning that is created during the RHCOS installation. However, there are cases where you might want to create a separate partition for a directory that you expect to grow.
OpenShift Container Platform supports the addition of a single partition to attach storage to either the /var
directory or a subdirectory of /var
. For example:
-
/var/lib/containers
: Holds container-related content that can grow as more images and containers are added to a system. -
/var/lib/etcd
: Holds data that you might want to keep separate for purposes such as performance optimization of etcd storage. /var
: Holds data that you might want to keep separate for purposes such as auditing.ImportantFor disk sizes larger than 100GB, and especially larger than 1TB, create a separate
/var
partition.
Storing the contents of a /var
directory separately makes it easier to grow storage for those areas as needed and reinstall OpenShift Container Platform at a later date and keep that data intact. With this method, you will not have to pull all your containers again, nor will you have to copy massive log files when you update systems.
The use of a separate partition for the /var
directory or a subdirectory of /var
also prevents data growth in the partitioned directory from filling up the root file system.
The following procedure sets up a separate /var
partition by adding a machine config manifest that is wrapped into the Ignition config file for a node type during the preparation phase of an installation.
Procedure
On your installation host, change to the directory that contains the OpenShift Container Platform installation program and generate the Kubernetes manifests for the cluster:
$ openshift-install create manifests --dir <installation_directory>
Create a Butane config that configures the additional partition. For example, name the file
$HOME/clusterconfig/98-var-partition.bu
, change the disk device name to the name of the storage device on theworker
systems, and set the storage size as appropriate. This example places the/var
directory on a separate partition:variant: openshift version: 4.13.0 metadata: labels: machineconfiguration.openshift.io/role: worker name: 98-var-partition storage: disks: - device: /dev/disk/by-id/<device_name> 1 partitions: - label: var start_mib: <partition_start_offset> 2 size_mib: <partition_size> 3 number: 5 filesystems: - device: /dev/disk/by-partlabel/var path: /var format: xfs mount_options: [defaults, prjquota] 4 with_mount_unit: true
- 1
- The storage device name of the disk that you want to partition.
- 2
- When adding a data partition to the boot disk, a minimum offset value of 25000 mebibytes is recommended. The root file system is automatically resized to fill all available space up to the specified offset. If no offset value is specified, or if the specified value is smaller than the recommended minimum, the resulting root file system will be too small, and future reinstalls of RHCOS might overwrite the beginning of the data partition.
- 3
- The size of the data partition in mebibytes.
- 4
- The
prjquota
mount option must be enabled for filesystems used for container storage.
NoteWhen creating a separate
/var
partition, you cannot use different instance types for compute nodes, if the different instance types do not have the same device name.Create a manifest from the Butane config and save it to the
clusterconfig/openshift
directory. For example, run the following command:$ butane $HOME/clusterconfig/98-var-partition.bu -o $HOME/clusterconfig/openshift/98-var-partition.yaml
Create the Ignition config files:
$ openshift-install create ignition-configs --dir <installation_directory> 1
- 1
- For
<installation_directory>
, specify the same installation directory.
Ignition config files are created for the bootstrap, control plane, and compute nodes in the installation directory:
. ├── auth │ ├── kubeadmin-password │ └── kubeconfig ├── bootstrap.ign ├── master.ign ├── metadata.json └── worker.ign
The files in the
<installation_directory>/manifest
and<installation_directory>/openshift
directories are wrapped into the Ignition config files, including the file that contains the98-var-partition
customMachineConfig
object.
Next steps
- You can apply the custom disk partitioning by referencing the Ignition config files during the RHCOS installations.
2.11.3.2.2. Retaining existing partitions
For an ISO installation, you can add options to the coreos-installer
command that cause the installer to maintain one or more existing partitions. For a PXE installation, you can add coreos.inst.*
options to the APPEND
parameter to preserve partitions.
Saved partitions might be data partitions from an existing OpenShift Container Platform system. You can identify the disk partitions you want to keep either by partition label or by number.
If you save existing partitions, and those partitions do not leave enough space for RHCOS, the installation will fail without damaging the saved partitions.
Retaining existing partitions during an ISO installation
This example preserves any partition in which the partition label begins with data
(data*
):
# coreos-installer install --ignition-url http://10.0.2.2:8080/user.ign \ --save-partlabel 'data*' /dev/disk/by-id/scsi-<serial_number>
The following example illustrates running the coreos-installer
in a way that preserves the sixth (6) partition on the disk:
# coreos-installer install --ignition-url http://10.0.2.2:8080/user.ign \ --save-partindex 6 /dev/disk/by-id/scsi-<serial_number>
This example preserves partitions 5 and higher:
# coreos-installer install --ignition-url http://10.0.2.2:8080/user.ign --save-partindex 5- /dev/disk/by-id/scsi-<serial_number>
In the previous examples where partition saving is used, coreos-installer
recreates the partition immediately.
Retaining existing partitions during a PXE installation
This APPEND
option preserves any partition in which the partition label begins with 'data' ('data*'):
coreos.inst.save_partlabel=data*
This APPEND
option preserves partitions 5 and higher:
coreos.inst.save_partindex=5-
This APPEND
option preserves partition 6:
coreos.inst.save_partindex=6
2.11.3.3. Identifying Ignition configs
When doing an RHCOS manual installation, there are two types of Ignition configs that you can provide, with different reasons for providing each one:
Permanent install Ignition config: Every manual RHCOS installation needs to pass one of the Ignition config files generated by
openshift-installer
, such asbootstrap.ign
,master.ign
andworker.ign
, to carry out the installation.ImportantIt is not recommended to modify these Ignition config files directly. You can update the manifest files that are wrapped into the Ignition config files, as outlined in examples in the preceding sections.
For PXE installations, you pass the Ignition configs on the
APPEND
line using thecoreos.inst.ignition_url=
option. For ISO installations, after the ISO boots to the shell prompt, you identify the Ignition config on thecoreos-installer
command line with the--ignition-url=
option. In both cases, only HTTP and HTTPS protocols are supported.Live install Ignition config: This type can be created by using the
coreos-installer
customize
subcommand and its various options. With this method, the Ignition config passes to the live install medium, runs immediately upon booting, and performs setup tasks before or after the RHCOS system installs to disk. This method should only be used for performing tasks that must be done once and not applied again later, such as with advanced partitioning that cannot be done using a machine config.For PXE or ISO boots, you can create the Ignition config and
APPEND
theignition.config.url=
option to identify the location of the Ignition config. You also need to appendignition.firstboot ignition.platform.id=metal
or theignition.config.url
option will be ignored.
2.11.3.4. Default console configuration
Red Hat Enterprise Linux CoreOS (RHCOS) nodes installed from an OpenShift Container Platform 4.13 boot image use a default console that is meant to accomodate most virtualized and bare metal setups. Different cloud and virtualization platforms may use different default settings depending on the chosen architecture. Bare metal installations use the kernel default settings which typically means the graphical console is the primary console and the serial console is disabled.
The default consoles may not match your specific hardware configuration or you might have specific needs that require you to adjust the default console. For example:
- You want to access the emergency shell on the console for debugging purposes.
- Your cloud platform does not provide interactive access to the graphical console, but provides a serial console.
- You want to enable multiple consoles.
Console configuration is inherited from the boot image. This means that new nodes in existing clusters are unaffected by changes to the default console.
You can configure the console for bare metal installations in the following ways:
-
Using
coreos-installer
manually on the command line. -
Using the
coreos-installer iso customize
orcoreos-installer pxe customize
subcommands with the--dest-console
option to create a custom image that automates the process.
For advanced customization, perform console configuration using the coreos-installer iso
or coreos-installer pxe
subcommands, and not kernel arguments.
2.11.3.5. Enabling the serial console for PXE and ISO installations
By default, the Red Hat Enterprise Linux CoreOS (RHCOS) serial console is disabled and all output is written to the graphical console. You can enable the serial console for an ISO installation and reconfigure the bootloader so that output is sent to both the serial console and the graphical console.
Procedure
- Boot the ISO installer.
Run the
coreos-installer
command to install the system, adding the--console
option once to specify the graphical console, and a second time to specify the serial console:$ coreos-installer install \ --console=tty0 \1 --console=ttyS0,<options> \2 --ignition-url=http://host/worker.ign /dev/disk/by-id/scsi-<serial_number>
- 1
- The desired secondary console. In this case, the graphical console. Omitting this option will disable the graphical console.
- 2
- The desired primary console. In this case the serial console. The
options
field defines the baud rate and other settings. A common value for this field is11520n8
. If no options are provided, the default kernel value of9600n8
is used. For more information on the format of this option, see Linux kernel serial console documentation.
Reboot into the installed system.
NoteA similar outcome can be obtained by using the
coreos-installer install --append-karg
option, and specifying the console withconsole=
. However, this will only set the console for the kernel and not the bootloader.
To configure a PXE installation, make sure the coreos.inst.install_dev
kernel command line option is omitted, and use the shell prompt to run coreos-installer
manually using the above ISO installation procedure.
2.11.3.6. Customizing a live RHCOS ISO or PXE install
You can use the live ISO image or PXE environment to install RHCOS by injecting an Ignition config file directly into the image. This creates a customized image that you can use to provision your system.
For an ISO image, the mechanism to do this is the coreos-installer iso customize
subcommand, which modifies the .iso
file with your configuration. Similarly, the mechanism for a PXE environment is the coreos-installer pxe customize
subcommand, which creates a new initramfs
file that includes your customizations.
The customize
subcommand is a general purpose tool that can embed other types of customizations as well. The following tasks are examples of some of the more common customizations:
- Inject custom CA certificates for when corporate security policy requires their use.
- Configure network settings without the need for kernel arguments.
- Embed arbitrary preinstall and post-install scripts or binaries.
2.11.3.7. Customizing a live RHCOS ISO image
You can customize a live RHCOS ISO image directly with the coreos-installer iso customize
subcommand. When you boot the ISO image, the customizations are applied automatically.
You can use this feature to configure the ISO image to automatically install RHCOS.
Procedure
-
Download the
coreos-installer
binary from thecoreos-installer
image mirror page. Retrieve the RHCOS ISO image from the RHCOS image mirror page and the Ignition config file, and then run the following command to inject the Ignition config directly into the ISO image:
$ coreos-installer iso customize rhcos-<version>-live.x86_64.iso \ --dest-ignition bootstrap.ign \ 1 --dest-device /dev/disk/by-id/scsi-<serial_number> 2
- 1
- The Ignition config file that is generated from the
openshift-installer
installation program. - 2
- When you specify this option, the ISO image automatically runs an installation. Otherwise, the image remains configured for installation, but does not install automatically unless you specify the
coreos.inst.install_dev
kernel argument.
Optional: To remove the ISO image customizations and return the image to its pristine state, run:
$ coreos-installer iso reset rhcos-<version>-live.x86_64.iso
You can now re-customize the live ISO image or use it in its pristine state.
Applying your customizations affects every subsequent boot of RHCOS.
2.11.3.7.1. Modifying a live install ISO image to enable the serial console
On clusters installed with OpenShift Container Platform 4.12 and above, the serial console is disabled by default and all output is written to the graphical console. You can enable the serial console with the following procedure.
Procedure
-
Download the
coreos-installer
binary from thecoreos-installer
image mirror page. Retrieve the RHCOS ISO image from the RHCOS image mirror page and run the following command to customize the ISO image to enable the serial console to receive output:
$ coreos-installer iso customize rhcos-<version>-live.x86_64.iso \ --dest-ignition <path> \1 --dest-console tty0 \2 --dest-console ttyS0,<options> \3 --dest-device /dev/disk/by-id/scsi-<serial_number> 4
- 1
- The location of the Ignition config to install.
- 2
- The desired secondary console. In this case, the graphical console. Omitting this option will disable the graphical console.
- 3
- The desired primary console. In this case, the serial console. The
options
field defines the baud rate and other settings. A common value for this field is115200n8
. If no options are provided, the default kernel value of9600n8
is used. For more information on the format of this option, see the Linux kernel serial console documentation. - 4
- The specified disk to install to. If you omit this option, the ISO image automatically runs the installation program which will fail unless you also specify the
coreos.inst.install_dev
kernel argument.
NoteThe
--dest-console
option affects the installed system and not the live ISO system. To modify the console for a live ISO system, use the--live-karg-append
option and specify the console withconsole=
.Your customizations are applied and affect every subsequent boot of the ISO image.
Optional: To remove the ISO image customizations and return the image to its original state, run the following command:
$ coreos-installer iso reset rhcos-<version>-live.x86_64.iso
You can now recustomize the live ISO image or use it in its original state.
2.11.3.7.2. Modifying a live install ISO image to use a custom certificate authority
You can provide certificate authority (CA) certificates to Ignition with the --ignition-ca
flag of the customize
subcommand. You can use the CA certificates during both the installation boot and when provisioning the installed system.
Custom CA certificates affect how Ignition fetches remote resources but they do not affect the certificates installed onto the system.
Procedure
-
Download the
coreos-installer
binary from thecoreos-installer
image mirror page. Retrieve the RHCOS ISO image from the RHCOS image mirror page and run the following command to customize the ISO image for use with a custom CA:
$ coreos-installer iso customize rhcos-<version>-live.x86_64.iso --ignition-ca cert.pem
The coreos.inst.ignition_url
kernel parameter does not work with the --ignition-ca
flag. You must use the --dest-ignition
flag to create a customized image for each cluster.
Applying your custom CA certificate affects every subsequent boot of RHCOS.
2.11.3.7.3. Modifying a live install ISO image with customized network settings
You can embed a NetworkManager keyfile into the live ISO image and pass it through to the installed system with the --network-keyfile
flag of the customize
subcommand.
When creating a connection profile, you must use a .nmconnection
filename extension in the filename of the connection profile. If you do not use a .nmconnection
filename extension, the cluster will apply the connection profile to the live environment, but it will not apply the configuration when the cluster first boots up the nodes, resulting in a setup that does not work.
Procedure
-
Download the
coreos-installer
binary from thecoreos-installer
image mirror page. Create a connection profile for a bonded interface. For example, create the
bond0.nmconnection
file in your local directory with the following content:[connection] id=bond0 type=bond interface-name=bond0 multi-connect=1 [bond] miimon=100 mode=active-backup [ipv4] method=auto [ipv6] method=auto
Create a connection profile for a secondary interface to add to the bond. For example, create the
bond0-proxy-em1.nmconnection
file in your local directory with the following content:[connection] id=em1 type=ethernet interface-name=em1 master=bond0 multi-connect=1 slave-type=bond
Create a connection profile for a secondary interface to add to the bond. For example, create the
bond0-proxy-em2.nmconnection
file in your local directory with the following content:[connection] id=em2 type=ethernet interface-name=em2 master=bond0 multi-connect=1 slave-type=bond
Retrieve the RHCOS ISO image from the RHCOS image mirror page and run the following command to customize the ISO image with your configured networking:
$ coreos-installer iso customize rhcos-<version>-live.x86_64.iso \ --network-keyfile bond0.nmconnection \ --network-keyfile bond0-proxy-em1.nmconnection \ --network-keyfile bond0-proxy-em2.nmconnection
Network settings are applied to the live system and are carried over to the destination system.
2.11.3.8. Customizing a live RHCOS PXE environment
You can customize a live RHCOS PXE environment directly with the coreos-installer pxe customize
subcommand. When you boot the PXE environment, the customizations are applied automatically.
You can use this feature to configure the PXE environment to automatically install RHCOS.
Procedure
-
Download the
coreos-installer
binary from thecoreos-installer
image mirror page. Retrieve the RHCOS
kernel
,initramfs
androotfs
files from the RHCOS image mirror page and the Ignition config file, and then run the following command to create a newinitramfs
file that contains the customizations from your Ignition config:$ coreos-installer pxe customize rhcos-<version>-live-initramfs.x86_64.img \ --dest-ignition bootstrap.ign \ 1 --dest-device /dev/disk/by-id/scsi-<serial_number> \ 2 -o rhcos-<version>-custom-initramfs.x86_64.img 3
- 1
- The Ignition config file that is generated from
openshift-installer
. - 2
- When you specify this option, the PXE environment automatically runs an install. Otherwise, the image remains configured for installing, but does not do so automatically unless you specify the
coreos.inst.install_dev
kernel argument. - 3
- Use the customized
initramfs
file in your PXE configuration. Add theignition.firstboot
andignition.platform.id=metal
kernel arguments if they are not already present.
Applying your customizations affects every subsequent boot of RHCOS.
2.11.3.8.1. Modifying a live install PXE environment to enable the serial console
On clusters installed with OpenShift Container Platform 4.12 and above, the serial console is disabled by default and all output is written to the graphical console. You can enable the serial console with the following procedure.
Procedure
-
Download the
coreos-installer
binary from thecoreos-installer
image mirror page. Retrieve the RHCOS
kernel
,initramfs
androotfs
files from the RHCOS image mirror page and the Ignition config file, and then run the following command to create a new customizedinitramfs
file that enables the serial console to receive output:$ coreos-installer pxe customize rhcos-<version>-live-initramfs.x86_64.img \ --dest-ignition <path> \1 --dest-console tty0 \2 --dest-console ttyS0,<options> \3 --dest-device /dev/disk/by-id/scsi-<serial_number> \4 -o rhcos-<version>-custom-initramfs.x86_64.img 5
- 1
- The location of the Ignition config to install.
- 2
- The desired secondary console. In this case, the graphical console. Omitting this option will disable the graphical console.
- 3
- The desired primary console. In this case, the serial console. The
options
field defines the baud rate and other settings. A common value for this field is115200n8
. If no options are provided, the default kernel value of9600n8
is used. For more information on the format of this option, see the Linux kernel serial console documentation. - 4
- The specified disk to install to. If you omit this option, the PXE environment automatically runs the installer which will fail unless you also specify the
coreos.inst.install_dev
kernel argument. - 5
- Use the customized
initramfs
file in your PXE configuration. Add theignition.firstboot
andignition.platform.id=metal
kernel arguments if they are not already present.
Your customizations are applied and affect every subsequent boot of the PXE environment.
2.11.3.8.2. Modifying a live install PXE environment to use a custom certificate authority
You can provide certificate authority (CA) certificates to Ignition with the --ignition-ca
flag of the customize
subcommand. You can use the CA certificates during both the installation boot and when provisioning the installed system.
Custom CA certificates affect how Ignition fetches remote resources but they do not affect the certificates installed onto the system.
Procedure
-
Download the
coreos-installer
binary from thecoreos-installer
image mirror page. Retrieve the RHCOS
kernel
,initramfs
androotfs
files from the RHCOS image mirror page and run the following command to create a new customizedinitramfs
file for use with a custom CA:$ coreos-installer pxe customize rhcos-<version>-live-initramfs.x86_64.img \ --ignition-ca cert.pem \ -o rhcos-<version>-custom-initramfs.x86_64.img
-
Use the customized
initramfs
file in your PXE configuration. Add theignition.firstboot
andignition.platform.id=metal
kernel arguments if they are not already present.
The coreos.inst.ignition_url
kernel parameter does not work with the --ignition-ca
flag. You must use the --dest-ignition
flag to create a customized image for each cluster.
Applying your custom CA certificate affects every subsequent boot of RHCOS.
2.11.3.8.3. Modifying a live install PXE environment with customized network settings
You can embed a NetworkManager keyfile into the live PXE environment and pass it through to the installed system with the --network-keyfile
flag of the customize
subcommand.
When creating a connection profile, you must use a .nmconnection
filename extension in the filename of the connection profile. If you do not use a .nmconnection
filename extension, the cluster will apply the connection profile to the live environment, but it will not apply the configuration when the cluster first boots up the nodes, resulting in a setup that does not work.
Procedure
-
Download the
coreos-installer
binary from thecoreos-installer
image mirror page. Create a connection profile for a bonded interface. For example, create the
bond0.nmconnection
file in your local directory with the following content:[connection] id=bond0 type=bond interface-name=bond0 multi-connect=1 [bond] miimon=100 mode=active-backup [ipv4] method=auto [ipv6] method=auto
Create a connection profile for a secondary interface to add to the bond. For example, create the
bond0-proxy-em1.nmconnection
file in your local directory with the following content:[connection] id=em1 type=ethernet interface-name=em1 master=bond0 multi-connect=1 slave-type=bond
Create a connection profile for a secondary interface to add to the bond. For example, create the
bond0-proxy-em2.nmconnection
file in your local directory with the following content:[connection] id=em2 type=ethernet interface-name=em2 master=bond0 multi-connect=1 slave-type=bond
Retrieve the RHCOS
kernel
,initramfs
androotfs
files from the RHCOS image mirror page and run the following command to create a new customizedinitramfs
file that contains your configured networking:$ coreos-installer pxe customize rhcos-<version>-live-initramfs.x86_64.img \ --network-keyfile bond0.nmconnection \ --network-keyfile bond0-proxy-em1.nmconnection \ --network-keyfile bond0-proxy-em2.nmconnection \ -o rhcos-<version>-custom-initramfs.x86_64.img
Use the customized
initramfs
file in your PXE configuration. Add theignition.firstboot
andignition.platform.id=metal
kernel arguments if they are not already present.Network settings are applied to the live system and are carried over to the destination system.
2.11.3.9. Advanced RHCOS installation reference
This section illustrates the networking configuration and other advanced options that allow you to modify the Red Hat Enterprise Linux CoreOS (RHCOS) manual installation process. The following tables describe the kernel arguments and command-line options you can use with the RHCOS live installer and the coreos-installer
command.
2.11.3.9.1. Networking and bonding options for ISO installations
If you install RHCOS from an ISO image, you can add kernel arguments manually when you boot the image to configure networking for a node. If no networking arguments are specified, DHCP is activated in the initramfs when RHCOS detects that networking is required to fetch the Ignition config file.
When adding networking arguments manually, you must also add the rd.neednet=1
kernel argument to bring the network up in the initramfs.
The following information provides examples for configuring networking and bonding on your RHCOS nodes for ISO installations. The examples describe how to use the ip=
, nameserver=
, and bond=
kernel arguments.
Ordering is important when adding the kernel arguments: ip=
, nameserver=
, and then bond=
.
The networking options are passed to the dracut
tool during system boot. For more information about the networking options supported by dracut
, see the dracut.cmdline
manual page.
The following examples are the networking options for ISO installation.
Configuring DHCP or static IP addresses
To configure an IP address, either use DHCP (ip=dhcp
) or set an individual static IP address (ip=<host_ip>
). If setting a static IP, you must then identify the DNS server IP address (nameserver=<dns_ip>
) on each node. The following example sets:
-
The node’s IP address to
10.10.10.2
-
The gateway address to
10.10.10.254
-
The netmask to
255.255.255.0
-
The hostname to
core0.example.com
-
The DNS server address to
4.4.4.41
-
The auto-configuration value to
none
. No auto-configuration is required when IP networking is configured statically.
ip=10.10.10.2::10.10.10.254:255.255.255.0:core0.example.com:enp1s0:none nameserver=4.4.4.41
When you use DHCP to configure IP addressing for the RHCOS machines, the machines also obtain the DNS server information through DHCP. For DHCP-based deployments, you can define the DNS server address that is used by the RHCOS nodes through your DHCP server configuration.
Configuring an IP address without a static hostname
You can configure an IP address without assigning a static hostname. If a static hostname is not set by the user, it will be picked up and automatically set by a reverse DNS lookup. To configure an IP address without a static hostname refer to the following example:
-
The node’s IP address to
10.10.10.2
-
The gateway address to
10.10.10.254
-
The netmask to
255.255.255.0
-
The DNS server address to
4.4.4.41
-
The auto-configuration value to
none
. No auto-configuration is required when IP networking is configured statically.
ip=10.10.10.2::10.10.10.254:255.255.255.0::enp1s0:none nameserver=4.4.4.41
Specifying multiple network interfaces
You can specify multiple network interfaces by setting multiple ip=
entries.
ip=10.10.10.2::10.10.10.254:255.255.255.0:core0.example.com:enp1s0:none ip=10.10.10.3::10.10.10.254:255.255.255.0:core0.example.com:enp2s0:none
Configuring default gateway and route
Optional: You can configure routes to additional networks by setting an rd.route=
value.
When you configure one or multiple networks, one default gateway is required. If the additional network gateway is different from the primary network gateway, the default gateway must be the primary network gateway.
Run the following command to configure the default gateway:
ip=::10.10.10.254::::
Enter the following command to configure the route for the additional network:
rd.route=20.20.20.0/24:20.20.20.254:enp2s0
Disabling DHCP on a single interface
You can disable DHCP on a single interface, such as when there are two or more network interfaces and only one interface is being used. In the example, the enp1s0
interface has a static networking configuration and DHCP is disabled for enp2s0
, which is not used:
ip=10.10.10.2::10.10.10.254:255.255.255.0:core0.example.com:enp1s0:none ip=::::core0.example.com:enp2s0:none
Combining DHCP and static IP configurations
You can combine DHCP and static IP configurations on systems with multiple network interfaces, for example:
ip=enp1s0:dhcp ip=10.10.10.2::10.10.10.254:255.255.255.0:core0.example.com:enp2s0:none
Configuring VLANs on individual interfaces
Optional: You can configure VLANs on individual interfaces by using the vlan=
parameter.
To configure a VLAN on a network interface and use a static IP address, run the following command:
ip=10.10.10.2::10.10.10.254:255.255.255.0:core0.example.com:enp2s0.100:none vlan=enp2s0.100:enp2s0
To configure a VLAN on a network interface and to use DHCP, run the following command:
ip=enp2s0.100:dhcp vlan=enp2s0.100:enp2s0
Providing multiple DNS servers
You can provide multiple DNS servers by adding a nameserver=
entry for each server, for example:
nameserver=1.1.1.1 nameserver=8.8.8.8
Bonding multiple network interfaces to a single interface
Optional: You can bond multiple network interfaces to a single interface by using the bond=
option. Refer to the following examples:
The syntax for configuring a bonded interface is:
bond=<name>[:<network_interfaces>][:options]
<name>
is the bonding device name (bond0
),<network_interfaces>
represents a comma-separated list of physical (ethernet) interfaces (em1,em2
), and options is a comma-separated list of bonding options. Entermodinfo bonding
to see available options.When you create a bonded interface using
bond=
, you must specify how the IP address is assigned and other information for the bonded interface.To configure the bonded interface to use DHCP, set the bond’s IP address to
dhcp
. For example:bond=bond0:em1,em2:mode=active-backup ip=bond0:dhcp
To configure the bonded interface to use a static IP address, enter the specific IP address you want and related information. For example:
bond=bond0:em1,em2:mode=active-backup ip=10.10.10.2::10.10.10.254:255.255.255.0:core0.example.com:bond0:none
Bonding multiple SR-IOV network interfaces to a dual port NIC interface
Support for Day 1 operations associated with enabling NIC partitioning for SR-IOV devices is a Technology Preview feature only. Technology Preview features are not supported with Red Hat production service level agreements (SLAs) and might not be functionally complete. Red Hat does not recommend using them in production. These features provide early access to upcoming product features, enabling customers to test functionality and provide feedback during the development process.
For more information about the support scope of Red Hat Technology Preview features, see Technology Preview Features Support Scope.
Optional: You can bond multiple SR-IOV network interfaces to a dual port NIC interface by using the bond=
option.
On each node, you must perform the following tasks:
- Create the SR-IOV virtual functions (VFs) following the guidance in Managing SR-IOV devices. Follow the procedure in the "Attaching SR-IOV networking devices to virtual machines" section.
- Create the bond, attach the desired VFs to the bond and set the bond link state up following the guidance in Configuring network bonding. Follow any of the described procedures to create the bond.
The following examples illustrate the syntax you must use:
The syntax for configuring a bonded interface is
bond=<name>[:<network_interfaces>][:options]
.<name>
is the bonding device name (bond0
),<network_interfaces>
represents the virtual functions (VFs) by their known name in the kernel and shown in the output of theip link
command(eno1f0
,eno2f0
), and options is a comma-separated list of bonding options. Entermodinfo bonding
to see available options.When you create a bonded interface using
bond=
, you must specify how the IP address is assigned and other information for the bonded interface.To configure the bonded interface to use DHCP, set the bond’s IP address to
dhcp
. For example:bond=bond0:eno1f0,eno2f0:mode=active-backup ip=bond0:dhcp
To configure the bonded interface to use a static IP address, enter the specific IP address you want and related information. For example:
bond=bond0:eno1f0,eno2f0:mode=active-backup ip=10.10.10.2::10.10.10.254:255.255.255.0:core0.example.com:bond0:none
Using network teaming
Optional: You can use a network teaming as an alternative to bonding by using the team=
parameter:
The syntax for configuring a team interface is:
team=name[:network_interfaces]
name is the team device name (
team0
) and network_interfaces represents a comma-separated list of physical (ethernet) interfaces (em1, em2
).
Teaming is planned to be deprecated when RHCOS switches to an upcoming version of RHEL. For more information, see this Red Hat Knowledgebase Article.
Use the following example to configure a network team:
team=team0:em1,em2 ip=team0:dhcp
2.11.3.9.2. coreos-installer
options for ISO and PXE installations
You can install RHCOS by running coreos-installer install <options> <device>
at the command prompt, after booting into the RHCOS live environment from an ISO image.
The following table shows the subcommands, options, and arguments you can pass to the coreos-installer
command.
coreos-installer install subcommand | |
Subcommand | Description |
| Embed an Ignition config in an ISO image. |
coreos-installer install subcommand options | |
Option | Description |
| Specify the image URL manually. |
| Specify a local image file manually. Used for debugging. |
| Embed an Ignition config from a file. |
| Embed an Ignition config from a URL. |
|
Digest |
| Override the Ignition platform ID for the installed system. |
|
Set the kernel and bootloader console for the installed system. For more information about the format of |
| Append a default kernel argument to the installed system. |
| Delete a default kernel argument from the installed system. |
| Copy the network configuration from the install environment. Important
The |
|
For use with |
| Save partitions with this label glob. |
| Save partitions with this number or range. |
| Skip RHCOS image signature verification. |
| Allow Ignition URL without HTTPS or hash. |
|
Target CPU architecture. Valid values are |
| Do not clear partition table on error. |
| Print help information. |
coreos-installer install subcommand argument | |
Argument | Description |
| The destination device. |
coreos-installer ISO subcommands | |
Subcommand | Description |
| Customize a RHCOS live ISO image. |
| Restore a RHCOS live ISO image to default settings. |
| Remove the embedded Ignition config from an ISO image. |
coreos-installer ISO customize subcommand options | |
Option | Description |
| Merge the specified Ignition config file into a new configuration fragment for the destination system. |
| Specify the kernel and bootloader console for the destination system. |
| Install and overwrite the specified destination device. |
| Add a kernel argument to each boot of the destination system. |
| Delete a kernel argument from each boot of the destination system. |
| Configure networking by using the specified NetworkManager keyfile for live and destination systems. |
| Specify an additional TLS certificate authority to be trusted by Ignition. |
| Run the specified script before installation. |
| Run the specified script after installation. |
| Apply the specified installer configuration file. |
| Merge the specified Ignition config file into a new configuration fragment for the live environment. |
| Add a kernel argument to each boot of the live environment. |
| Delete a kernel argument from each boot of the live environment. |
|
Replace a kernel argument in each boot of the live environment, in the form |
| Overwrite an existing Ignition config. |
| Write the ISO to a new output file. |
| Print help information. |
coreos-installer PXE subcommands | |
Subcommand | Description |
Note that not all of these options are accepted by all subcommands. | |
| Customize a RHCOS live PXE boot config. |
| Wrap an Ignition config in an image. |
| Show the wrapped Ignition config in an image. |
coreos-installer PXE customize subcommand options | |
Option | Description |
Note that not all of these options are accepted by all subcommands. | |
| Merge the specified Ignition config file into a new configuration fragment for the destination system. |
| Specify the kernel and bootloader console for the destination system. |
| Install and overwrite the specified destination device. |
| Configure networking by using the specified NetworkManager keyfile for live and destination systems. |
| Specify an additional TLS certificate authority to be trusted by Ignition. |
| Run the specified script before installation. |
| Run the specified script after installation. |
| Apply the specified installer configuration file. |
| Merge the specified Ignition config file into a new configuration fragment for the live environment. |
| Write the initramfs to a new output file. Note This option is required for PXE environments. |
| Print help information. |
2.11.3.9.3. coreos.inst
boot options for ISO or PXE installations
You can automatically invoke coreos-installer
options at boot time by passing coreos.inst
boot arguments to the RHCOS live installer. These are provided in addition to the standard boot arguments.
-
For ISO installations, the
coreos.inst
options can be added by interrupting the automatic boot at the bootloader menu. You can interrupt the automatic boot by pressingTAB
while the RHEL CoreOS (Live) menu option is highlighted. -
For PXE or iPXE installations, the
coreos.inst
options must be added to theAPPEND
line before the RHCOS live installer is booted.
The following table shows the RHCOS live installer coreos.inst
boot options for ISO and PXE installations.
Argument | Description |
---|---|
|
Required. The block device on the system to install to. It is recommended to use the full path, such as |
| Optional: The URL of the Ignition config to embed into the installed system. If no URL is specified, no Ignition config is embedded. Only HTTP and HTTPS protocols are supported. |
| Optional: Comma-separated labels of partitions to preserve during the install. Glob-style wildcards are permitted. The specified partitions do not need to exist. |
|
Optional: Comma-separated indexes of partitions to preserve during the install. Ranges |
|
Optional: Permits the OS image that is specified by |
| Optional: Download and install the specified RHCOS image.
|
| Optional: The system will not reboot after installing. After the install finishes, you will receive a prompt that allows you to inspect what is happening during installation. This argument should not be used in production environments and is intended for debugging purposes only. |
|
Optional: The Ignition platform ID of the platform the RHCOS image is being installed on. Default is |
|
Optional: The URL of the Ignition config for the live boot. For example, this can be used to customize how |
2.11.4. Enabling multipathing with kernel arguments on RHCOS
RHCOS supports multipathing on the primary disk, allowing stronger resilience to hardware failure to achieve higher host availability.
You can enable multipathing at installation time for nodes that were provisioned in OpenShift Container Platform 4.8 or later. While postinstallation support is available by activating multipathing via the machine config, enabling multipathing during installation is recommended.
In setups where any I/O to non-optimized paths results in I/O system errors, you must enable multipathing at installation time.
On IBM Z and IBM® LinuxONE, you can enable multipathing only if you configured your cluster for it during installation. For more information, see "Installing RHCOS and starting the OpenShift Container Platform bootstrap process" in Installing a cluster with z/VM on IBM Z and IBM® LinuxONE.
The following procedure enables multipath at installation time and appends kernel arguments to the coreos-installer install
command so that the installed system itself will use multipath beginning from the first boot.
OpenShift Container Platform does not support enabling multipathing as a day-2 activity on nodes that have been upgraded from 4.6 or earlier.
Prerequisites
- You have created the Ignition config files for your cluster.
- You have reviewed Installing RHCOS and starting the OpenShift Container Platform bootstrap process.
Procedure
To enable multipath and start the
multipathd
daemon, run the following command on the installation host:$ mpathconf --enable && systemctl start multipathd.service
-
Optional: If booting the PXE or ISO, you can instead enable multipath by adding
rd.multipath=default
from the kernel command line.
-
Optional: If booting the PXE or ISO, you can instead enable multipath by adding
Append the kernel arguments by invoking the
coreos-installer
program:If there is only one multipath device connected to the machine, it should be available at path
/dev/mapper/mpatha
. For example:$ coreos-installer install /dev/mapper/mpatha \1 --ignition-url=http://host/worker.ign \ --append-karg rd.multipath=default \ --append-karg root=/dev/disk/by-label/dm-mpath-root \ --append-karg rw
- 1
- Indicates the path of the single multipathed device.
If there are multiple multipath devices connected to the machine, or to be more explicit, instead of using
/dev/mapper/mpatha
, it is recommended to use the World Wide Name (WWN) symlink available in/dev/disk/by-id
. For example:$ coreos-installer install /dev/disk/by-id/wwn-<wwn_ID> \1 --ignition-url=http://host/worker.ign \ --append-karg rd.multipath=default \ --append-karg root=/dev/disk/by-label/dm-mpath-root \ --append-karg rw
- 1
- Indicates the WWN ID of the target multipathed device. For example,
0xx194e957fcedb4841
.
This symlink can also be used as the
coreos.inst.install_dev
kernel argument when using specialcoreos.inst.*
arguments to direct the live installer. For more information, see "Installing RHCOS and starting the OpenShift Container Platform bootstrap process".
- Reboot into the installed system.
Check that the kernel arguments worked by going to one of the worker nodes and listing the kernel command line arguments (in
/proc/cmdline
on the host):$ oc debug node/ip-10-0-141-105.ec2.internal
Example output
Starting pod/ip-10-0-141-105ec2internal-debug ... To use host binaries, run `chroot /host` sh-4.2# cat /host/proc/cmdline ... rd.multipath=default root=/dev/disk/by-label/dm-mpath-root ... sh-4.2# exit
You should see the added kernel arguments.
2.11.4.1. Enabling multipathing on secondary disks
RHCOS also supports multipathing on a secondary disk. Instead of kernel arguments, you use Ignition to enable multipathing for the secondary disk at installation time.
Prerequisites
- You have read the section Disk partitioning.
- You have read Enabling multipathing with kernel arguments on RHCOS.
- You have installed the Butane utility.
Procedure
Create a Butane config with information similar to the following:
Example
multipath-config.bu
variant: openshift version: 4.13.0 systemd: units: - name: mpath-configure.service enabled: true contents: | [Unit] Description=Configure Multipath on Secondary Disk ConditionFirstBoot=true ConditionPathExists=!/etc/multipath.conf Before=multipathd.service 1 DefaultDependencies=no [Service] Type=oneshot ExecStart=/usr/sbin/mpathconf --enable 2 [Install] WantedBy=multi-user.target - name: mpath-var-lib-container.service enabled: true contents: | [Unit] Description=Set Up Multipath On /var/lib/containers ConditionFirstBoot=true 3 Requires=dev-mapper-mpatha.device After=dev-mapper-mpatha.device After=ostree-remount.service Before=kubelet.service DefaultDependencies=no [Service] 4 Type=oneshot ExecStart=/usr/sbin/mkfs.xfs -L containers -m reflink=1 /dev/mapper/mpatha ExecStart=/usr/bin/mkdir -p /var/lib/containers [Install] WantedBy=multi-user.target - name: var-lib-containers.mount enabled: true contents: | [Unit] Description=Mount /var/lib/containers After=mpath-var-lib-containers.service Before=kubelet.service 5 [Mount] 6 What=/dev/disk/by-label/dm-mpath-containers Where=/var/lib/containers Type=xfs [Install] WantedBy=multi-user.target
- 1
- The configuration must be set before launching the multipath daemon.
- 2
- Starts the
mpathconf
utility. - 3
- This field must be set to the value
true
. - 4
- Creates the filesystem and directory
/var/lib/containers
. - 5
- The device must be mounted before starting any nodes.
- 6
- Mounts the device to the
/var/lib/containers
mount point. This location cannot be a symlink.
Create the Ignition configuration by running the following command:
$ butane --pretty --strict multipath-config.bu > multipath-config.ign
Continue with the rest of the first boot RHCOS installation process.
ImportantDo not add the
rd.multipath
orroot
kernel arguments on the command-line during installation unless the primary disk is also multipathed.
Additional resources
-
See Installing RHCOS and starting the OpenShift Container Platform bootstrap process for more information on using special
coreos.inst.*
arguments to direct the live installer.
2.12. Waiting for the bootstrap process to complete
The OpenShift Container Platform bootstrap process begins after the cluster nodes first boot into the persistent RHCOS environment that has been installed to disk. The configuration information provided through the Ignition config files is used to initialize the bootstrap process and install OpenShift Container Platform on the machines. You must wait for the bootstrap process to complete.
Prerequisites
- You have created the Ignition config files for your cluster.
- You have configured suitable network, DNS and load balancing infrastructure.
- You have obtained the installation program and generated the Ignition config files for your cluster.
- You installed RHCOS on your cluster machines and provided the Ignition config files that the OpenShift Container Platform installation program generated.
- Your machines have direct internet access or have an HTTP or HTTPS proxy available.
Procedure
Monitor the bootstrap process:
$ ./openshift-install --dir <installation_directory> wait-for bootstrap-complete \ 1 --log-level=info 2
Example output
INFO Waiting up to 30m0s for the Kubernetes API at https://api.test.example.com:6443... INFO API v1.26.0 up INFO Waiting up to 30m0s for bootstrapping to complete... INFO It is now safe to remove the bootstrap resources
The command succeeds when the Kubernetes API server signals that it has been bootstrapped on the control plane machines.
After the bootstrap process is complete, remove the bootstrap machine from the load balancer.
ImportantYou must remove the bootstrap machine from the load balancer at this point. You can also remove or reformat the bootstrap machine itself.
Additional resources
- See Monitoring installation progress for more information about monitoring the installation logs and retrieving diagnostic data if installation issues arise.
2.13. Logging in to the cluster by using the CLI
You can log in to your cluster as a default system user by exporting the cluster kubeconfig
file. The kubeconfig
file contains information about the cluster that is used by the CLI to connect a client to the correct cluster and API server. The file is specific to a cluster and is created during OpenShift Container Platform installation.
Prerequisites
- You deployed an OpenShift Container Platform cluster.
-
You installed the
oc
CLI.
Procedure
Export the
kubeadmin
credentials:$ export KUBECONFIG=<installation_directory>/auth/kubeconfig 1
- 1
- For
<installation_directory>
, specify the path to the directory that you stored the installation files in.
Verify you can run
oc
commands successfully using the exported configuration:$ oc whoami
Example output
system:admin
2.14. Approving the certificate signing requests for your machines
When you add machines to a cluster, two pending certificate signing requests (CSRs) are generated for each machine that you added. You must confirm that these CSRs are approved or, if necessary, approve them yourself. The client requests must be approved first, followed by the server requests.
Prerequisites
- You added machines to your cluster.
Procedure
Confirm that the cluster recognizes the machines:
$ oc get nodes
Example output
NAME STATUS ROLES AGE VERSION master-0 Ready master 63m v1.26.0 master-1 Ready master 63m v1.26.0 master-2 Ready master 64m v1.26.0
The output lists all of the machines that you created.
NoteThe preceding output might not include the compute nodes, also known as worker nodes, until some CSRs are approved.
Review the pending CSRs and ensure that you see the client requests with the
Pending
orApproved
status for each machine that you added to the cluster:$ oc get csr
Example output
NAME AGE REQUESTOR CONDITION csr-8b2br 15m system:serviceaccount:openshift-machine-config-operator:node-bootstrapper Pending csr-8vnps 15m system:serviceaccount:openshift-machine-config-operator:node-bootstrapper Pending ...
In this example, two machines are joining the cluster. You might see more approved CSRs in the list.
If the CSRs were not approved, after all of the pending CSRs for the machines you added are in
Pending
status, approve the CSRs for your cluster machines:NoteBecause the CSRs rotate automatically, approve your CSRs within an hour of adding the machines to the cluster. If you do not approve them within an hour, the certificates will rotate, and more than two certificates will be present for each node. You must approve all of these certificates. After the client CSR is approved, the Kubelet creates a secondary CSR for the serving certificate, which requires manual approval. Then, subsequent serving certificate renewal requests are automatically approved by the
machine-approver
if the Kubelet requests a new certificate with identical parameters.NoteFor clusters running on platforms that are not machine API enabled, such as bare metal and other user-provisioned infrastructure, you must implement a method of automatically approving the kubelet serving certificate requests (CSRs). If a request is not approved, then the
oc exec
,oc rsh
, andoc logs
commands cannot succeed, because a serving certificate is required when the API server connects to the kubelet. Any operation that contacts the Kubelet endpoint requires this certificate approval to be in place. The method must watch for new CSRs, confirm that the CSR was submitted by thenode-bootstrapper
service account in thesystem:node
orsystem:admin
groups, and confirm the identity of the node.To approve them individually, run the following command for each valid CSR:
$ oc adm certificate approve <csr_name> 1
- 1
<csr_name>
is the name of a CSR from the list of current CSRs.
To approve all pending CSRs, run the following command:
$ oc get csr -o go-template='{{range .items}}{{if not .status}}{{.metadata.name}}{{"\n"}}{{end}}{{end}}' | xargs --no-run-if-empty oc adm certificate approve
NoteSome Operators might not become available until some CSRs are approved.
Now that your client requests are approved, you must review the server requests for each machine that you added to the cluster:
$ oc get csr
Example output
NAME AGE REQUESTOR CONDITION csr-bfd72 5m26s system:node:ip-10-0-50-126.us-east-2.compute.internal Pending csr-c57lv 5m26s system:node:ip-10-0-95-157.us-east-2.compute.internal Pending ...
If the remaining CSRs are not approved, and are in the
Pending
status, approve the CSRs for your cluster machines:To approve them individually, run the following command for each valid CSR:
$ oc adm certificate approve <csr_name> 1
- 1
<csr_name>
is the name of a CSR from the list of current CSRs.
To approve all pending CSRs, run the following command:
$ oc get csr -o go-template='{{range .items}}{{if not .status}}{{.metadata.name}}{{"\n"}}{{end}}{{end}}' | xargs oc adm certificate approve
After all client and server CSRs have been approved, the machines have the
Ready
status. Verify this by running the following command:$ oc get nodes
Example output
NAME STATUS ROLES AGE VERSION master-0 Ready master 73m v1.26.0 master-1 Ready master 73m v1.26.0 master-2 Ready master 74m v1.26.0 worker-0 Ready worker 11m v1.26.0 worker-1 Ready worker 11m v1.26.0
NoteIt can take a few minutes after approval of the server CSRs for the machines to transition to the
Ready
status.
Additional information
- For more information on CSRs, see Certificate Signing Requests.
2.15. Initial Operator configuration
After the control plane initializes, you must immediately configure some Operators so that they all become available.
Prerequisites
- Your control plane has initialized.
Procedure
Watch the cluster components come online:
$ watch -n5 oc get clusteroperators
Example output
NAME VERSION AVAILABLE PROGRESSING DEGRADED SINCE authentication 4.13.0 True False False 19m baremetal 4.13.0 True False False 37m cloud-credential 4.13.0 True False False 40m cluster-autoscaler 4.13.0 True False False 37m config-operator 4.13.0 True False False 38m console 4.13.0 True False False 26m csi-snapshot-controller 4.13.0 True False False 37m dns 4.13.0 True False False 37m etcd 4.13.0 True False False 36m image-registry 4.13.0 True False False 31m ingress 4.13.0 True False False 30m insights 4.13.0 True False False 31m kube-apiserver 4.13.0 True False False 26m kube-controller-manager 4.13.0 True False False 36m kube-scheduler 4.13.0 True False False 36m kube-storage-version-migrator 4.13.0 True False False 37m machine-api 4.13.0 True False False 29m machine-approver 4.13.0 True False False 37m machine-config 4.13.0 True False False 36m marketplace 4.13.0 True False False 37m monitoring 4.13.0 True False False 29m network 4.13.0 True False False 38m node-tuning 4.13.0 True False False 37m openshift-apiserver 4.13.0 True False False 32m openshift-controller-manager 4.13.0 True False False 30m openshift-samples 4.13.0 True False False 32m operator-lifecycle-manager 4.13.0 True False False 37m operator-lifecycle-manager-catalog 4.13.0 True False False 37m operator-lifecycle-manager-packageserver 4.13.0 True False False 32m service-ca 4.13.0 True False False 38m storage 4.13.0 True False False 37m
- Configure the Operators that are not available.
Additional resources
- See Gathering logs from a failed installation for details about gathering data in the event of a failed OpenShift Container Platform installation.
- See Troubleshooting Operator issues for steps to check Operator pod health across the cluster and gather Operator logs for diagnosis.
2.15.1. Image registry removed during installation
On platforms that do not provide shareable object storage, the OpenShift Image Registry Operator bootstraps itself as Removed
. This allows openshift-installer
to complete installations on these platform types.
After installation, you must edit the Image Registry Operator configuration to switch the managementState
from Removed
to Managed
. When this has completed, you must configure storage.
2.15.2. Image registry storage configuration
The Image Registry Operator is not initially available for platforms that do not provide default storage. After installation, you must configure your registry to use storage so that the Registry Operator is made available.
Instructions are shown for configuring a persistent volume, which is required for production clusters. Where applicable, instructions are shown for configuring an empty directory as the storage location, which is available for only non-production clusters.
Additional instructions are provided for allowing the image registry to use block storage types by using the Recreate
rollout strategy during upgrades.
2.15.2.1. Configuring registry storage for bare metal and other manual installations
As a cluster administrator, following installation you must configure your registry to use storage.
Prerequisites
-
You have access to the cluster as a user with the
cluster-admin
role. - You have a cluster that uses manually-provisioned Red Hat Enterprise Linux CoreOS (RHCOS) nodes, such as bare metal.
You have provisioned persistent storage for your cluster, such as Red Hat OpenShift Data Foundation.
ImportantOpenShift Container Platform supports
ReadWriteOnce
access for image registry storage when you have only one replica.ReadWriteOnce
access also requires that the registry uses theRecreate
rollout strategy. To deploy an image registry that supports high availability with two or more replicas,ReadWriteMany
access is required.- Must have 100Gi capacity.
Procedure
To configure your registry to use storage, change the
spec.storage.pvc
in theconfigs.imageregistry/cluster
resource.NoteWhen you use shared storage, review your security settings to prevent outside access.
Verify that you do not have a registry pod:
$ oc get pod -n openshift-image-registry -l docker-registry=default
Example output
No resources found in openshift-image-registry namespace
NoteIf you do have a registry pod in your output, you do not need to continue with this procedure.
Check the registry configuration:
$ oc edit configs.imageregistry.operator.openshift.io
Example output
storage: pvc: claim:
Leave the
claim
field blank to allow the automatic creation of animage-registry-storage
PVC.Check the
clusteroperator
status:$ oc get clusteroperator image-registry
Example output
NAME VERSION AVAILABLE PROGRESSING DEGRADED SINCE MESSAGE image-registry 4.13 True False False 6h50m
Ensure that your registry is set to managed to enable building and pushing of images.
Run:
$ oc edit configs.imageregistry/cluster
Then, change the line
managementState: Removed
to
managementState: Managed
2.15.2.2. Configuring storage for the image registry in non-production clusters
You must configure storage for the Image Registry Operator. For non-production clusters, you can set the image registry to an empty directory. If you do so, all images are lost if you restart the registry.
Procedure
To set the image registry storage to an empty directory:
$ oc patch configs.imageregistry.operator.openshift.io cluster --type merge --patch '{"spec":{"storage":{"emptyDir":{}}}}'
WarningConfigure this option for only non-production clusters.
If you run this command before the Image Registry Operator initializes its components, the
oc patch
command fails with the following error:Error from server (NotFound): configs.imageregistry.operator.openshift.io "cluster" not found
Wait a few minutes and run the command again.
2.15.2.3. Configuring block registry storage for bare metal
To allow the image registry to use block storage types during upgrades as a cluster administrator, you can use the Recreate
rollout strategy.
Block storage volumes, or block persistent volumes, are supported but not recommended for use with the image registry on production clusters. An installation where the registry is configured on block storage is not highly available because the registry cannot have more than one replica.
If you choose to use a block storage volume with the image registry, you must use a filesystem persistent volume claim (PVC).
Procedure
Enter the following command to set the image registry storage as a block storage type, patch the registry so that it uses the
Recreate
rollout strategy, and runs with only one (1
) replica:$ oc patch config.imageregistry.operator.openshift.io/cluster --type=merge -p '{"spec":{"rolloutStrategy":"Recreate","replicas":1}}'
Provision the PV for the block storage device, and create a PVC for that volume. The requested block volume uses the ReadWriteOnce (RWO) access mode.
Create a
pvc.yaml
file with the following contents to define a VMware vSpherePersistentVolumeClaim
object:kind: PersistentVolumeClaim apiVersion: v1 metadata: name: image-registry-storage 1 namespace: openshift-image-registry 2 spec: accessModes: - ReadWriteOnce 3 resources: requests: storage: 100Gi 4
- 1
- A unique name that represents the
PersistentVolumeClaim
object. - 2
- The namespace for the
PersistentVolumeClaim
object, which isopenshift-image-registry
. - 3
- The access mode of the persistent volume claim. With
ReadWriteOnce
, the volume can be mounted with read and write permissions by a single node. - 4
- The size of the persistent volume claim.
Enter the following command to create the
PersistentVolumeClaim
object from the file:$ oc create -f pvc.yaml -n openshift-image-registry
Enter the following command to edit the registry configuration so that it references the correct PVC:
$ oc edit config.imageregistry.operator.openshift.io -o yaml
Example output
storage: pvc: claim: 1
- 1
- By creating a custom PVC, you can leave the
claim
field blank for the default automatic creation of animage-registry-storage
PVC.
2.16. Completing installation on user-provisioned infrastructure
After you complete the Operator configuration, you can finish installing the cluster on infrastructure that you provide.
Prerequisites
- Your control plane has initialized.
- You have completed the initial Operator configuration.
Procedure
Confirm that all the cluster components are online with the following command:
$ watch -n5 oc get clusteroperators
Example output
NAME VERSION AVAILABLE PROGRESSING DEGRADED SINCE authentication 4.13.0 True False False 19m baremetal 4.13.0 True False False 37m cloud-credential 4.13.0 True False False 40m cluster-autoscaler 4.13.0 True False False 37m config-operator 4.13.0 True False False 38m console 4.13.0 True False False 26m csi-snapshot-controller 4.13.0 True False False 37m dns 4.13.0 True False False 37m etcd 4.13.0 True False False 36m image-registry 4.13.0 True False False 31m ingress 4.13.0 True False False 30m insights 4.13.0 True False False 31m kube-apiserver 4.13.0 True False False 26m kube-controller-manager 4.13.0 True False False 36m kube-scheduler 4.13.0 True False False 36m kube-storage-version-migrator 4.13.0 True False False 37m machine-api 4.13.0 True False False 29m machine-approver 4.13.0 True False False 37m machine-config 4.13.0 True False False 36m marketplace 4.13.0 True False False 37m monitoring 4.13.0 True False False 29m network 4.13.0 True False False 38m node-tuning 4.13.0 True False False 37m openshift-apiserver 4.13.0 True False False 32m openshift-controller-manager 4.13.0 True False False 30m openshift-samples 4.13.0 True False False 32m operator-lifecycle-manager 4.13.0 True False False 37m operator-lifecycle-manager-catalog 4.13.0 True False False 37m operator-lifecycle-manager-packageserver 4.13.0 True False False 32m service-ca 4.13.0 True False False 38m storage 4.13.0 True False False 37m
Alternatively, the following command notifies you when all of the clusters are available. It also retrieves and displays credentials:
$ ./openshift-install --dir <installation_directory> wait-for install-complete 1
- 1
- For
<installation_directory>
, specify the path to the directory that you stored the installation files in.
Example output
INFO Waiting up to 30m0s for the cluster to initialize...
The command succeeds when the Cluster Version Operator finishes deploying the OpenShift Container Platform cluster from Kubernetes API server.
Important-
The Ignition config files that the installation program generates contain certificates that expire after 24 hours, which are then renewed at that time. If the cluster is shut down before renewing the certificates and the cluster is later restarted after the 24 hours have elapsed, the cluster automatically recovers the expired certificates. The exception is that you must manually approve the pending
node-bootstrapper
certificate signing requests (CSRs) to recover kubelet certificates. See the documentation for Recovering from expired control plane certificates for more information. - It is recommended that you use Ignition config files within 12 hours after they are generated because the 24-hour certificate rotates from 16 to 22 hours after the cluster is installed. By using the Ignition config files within 12 hours, you can avoid installation failure if the certificate update runs during installation.
Confirm that the Kubernetes API server is communicating with the pods.
To view a list of all pods, use the following command:
$ oc get pods --all-namespaces
Example output
NAMESPACE NAME READY STATUS RESTARTS AGE openshift-apiserver-operator openshift-apiserver-operator-85cb746d55-zqhs8 1/1 Running 1 9m openshift-apiserver apiserver-67b9g 1/1 Running 0 3m openshift-apiserver apiserver-ljcmx 1/1 Running 0 1m openshift-apiserver apiserver-z25h4 1/1 Running 0 2m openshift-authentication-operator authentication-operator-69d5d8bf84-vh2n8 1/1 Running 0 5m ...
View the logs for a pod that is listed in the output of the previous command by using the following command:
$ oc logs <pod_name> -n <namespace> 1
- 1
- Specify the pod name and namespace, as shown in the output of the previous command.
If the pod logs display, the Kubernetes API server can communicate with the cluster machines.
For an installation with Fibre Channel Protocol (FCP), additional steps are required to enable multipathing. Do not enable multipathing during installation.
See "Enabling multipathing with kernel arguments on RHCOS" in the Post-installation machine configuration tasks documentation for more information.
2.17. Telemetry access for OpenShift Container Platform
In OpenShift Container Platform 4.13, the Telemetry service, which runs by default to provide metrics about cluster health and the success of updates, requires internet access. If your cluster is connected to the internet, Telemetry runs automatically, and your cluster is registered to OpenShift Cluster Manager Hybrid Cloud Console.
After you confirm that your OpenShift Cluster Manager Hybrid Cloud Console inventory is correct, either maintained automatically by Telemetry or manually by using OpenShift Cluster Manager, use subscription watch to track your OpenShift Container Platform subscriptions at the account or multi-cluster level.
Additional resources
- See About remote health monitoring for more information about the Telemetry service
2.18. Next steps
Chapter 3. Installing a user-provisioned bare metal cluster with network customizations
In OpenShift Container Platform 4.13, you can install a cluster on bare metal infrastructure that you provision with customized network configuration options. By customizing your network configuration, your cluster can coexist with existing IP address allocations in your environment and integrate with existing MTU and VXLAN configurations.
When you customize OpenShift Container Platform networking, you must set most of the network configuration parameters during installation. You can modify only kubeProxy
network configuration parameters in a running cluster.
3.1. Prerequisites
- You reviewed details about the OpenShift Container Platform installation and update processes.
- You read the documentation on selecting a cluster installation method and preparing it for users.
- If you use a firewall and plan to use the Telemetry service, you configured the firewall to allow the sites that your cluster requires access to.
3.2. Internet access for OpenShift Container Platform
In OpenShift Container Platform 4.13, you require access to the internet to install your cluster.
You must have internet access to:
- Access OpenShift Cluster Manager Hybrid Cloud Console to download the installation program and perform subscription management. If the cluster has internet access and you do not disable Telemetry, that service automatically entitles your cluster.
- Access Quay.io to obtain the packages that are required to install your cluster.
- Obtain the packages that are required to perform cluster updates.
If your cluster cannot have direct internet access, you can perform a restricted network installation on some types of infrastructure that you provision. During that process, you download the required content and use it to populate a mirror registry with the installation packages. With some installation types, the environment that you install your cluster in will not require internet access. Before you update the cluster, you update the content of the mirror registry.
Additional resources
- See Installing a user-provisioned bare metal cluster on a restricted network for more information about performing a restricted network installation on bare metal infrastructure that you provision.
3.3. Requirements for a cluster with user-provisioned infrastructure
For a cluster that contains user-provisioned infrastructure, you must deploy all of the required machines.
This section describes the requirements for deploying OpenShift Container Platform on user-provisioned infrastructure.
3.3.1. Required machines for cluster installation
The smallest OpenShift Container Platform clusters require the following hosts:
Hosts | Description |
---|---|
One temporary bootstrap machine | The cluster requires the bootstrap machine to deploy the OpenShift Container Platform cluster on the three control plane machines. You can remove the bootstrap machine after you install the cluster. |
Three control plane machines | The control plane machines run the Kubernetes and OpenShift Container Platform services that form the control plane. |
At least two compute machines, which are also known as worker machines. | The workloads requested by OpenShift Container Platform users run on the compute machines. |
As an exception, you can run zero compute machines in a bare metal cluster that consists of three control plane machines only. This provides smaller, more resource efficient clusters for cluster administrators and developers to use for testing, development, and production. Running one compute machine is not supported.
To maintain high availability of your cluster, use separate physical hosts for these cluster machines.
The bootstrap and control plane machines must use Red Hat Enterprise Linux CoreOS (RHCOS) as the operating system. However, the compute machines can choose between Red Hat Enterprise Linux CoreOS (RHCOS), Red Hat Enterprise Linux (RHEL) 8.6 and later.
Note that RHCOS is based on Red Hat Enterprise Linux (RHEL) 9.2 and inherits all of its hardware certifications and requirements. See Red Hat Enterprise Linux technology capabilities and limits.
3.3.2. Minimum resource requirements for cluster installation
Each cluster machine must meet the following minimum requirements:
Machine | Operating System | CPU [1] | RAM | Storage | Input/Output Per Second (IOPS)[2] |
---|---|---|---|---|---|
Bootstrap | RHCOS | 4 | 16 GB | 100 GB | 300 |
Control plane | RHCOS | 4 | 16 GB | 100 GB | 300 |
Compute | RHCOS, RHEL 8.6 and later [3] | 2 | 8 GB | 100 GB | 300 |
- One CPU is equivalent to one physical core when simultaneous multithreading (SMT), or Hyper-Threading, is not enabled. When enabled, use the following formula to calculate the corresponding ratio: (threads per core × cores) × sockets = CPUs.
- OpenShift Container Platform and Kubernetes are sensitive to disk performance, and faster storage is recommended, particularly for etcd on the control plane nodes which require a 10 ms p99 fsync duration. Note that on many cloud platforms, storage size and IOPS scale together, so you might need to over-allocate storage volume to obtain sufficient performance.
- As with all user-provisioned installations, if you choose to use RHEL compute machines in your cluster, you take responsibility for all operating system life cycle management and maintenance, including performing system updates, applying patches, and completing all other required tasks. Use of RHEL 7 compute machines is deprecated and has been removed in OpenShift Container Platform 4.10 and later.
As of OpenShift Container Platform version 4.13, RHCOS is based on RHEL version 9.2, which updates the micro-architecture requirements. The following list contains the minimum instruction set architectures (ISA) that each architecture requires:
- x86-64 architecture requires x86-64-v2 ISA
- ARM64 architecture requires ARMv8.0-A ISA
- IBM Power architecture requires Power 9 ISA
- s390x architecture requires z14 ISA
For more information, see RHEL Architectures.
If an instance type for your platform meets the minimum requirements for cluster machines, it is supported to use in OpenShift Container Platform.
Additional resources
3.3.3. Certificate signing requests management
Because your cluster has limited access to automatic machine management when you use infrastructure that you provision, you must provide a mechanism for approving cluster certificate signing requests (CSRs) after installation. The kube-controller-manager
only approves the kubelet client CSRs. The machine-approver
cannot guarantee the validity of a serving certificate that is requested by using kubelet credentials because it cannot confirm that the correct machine issued the request. You must determine and implement a method of verifying the validity of the kubelet serving certificate requests and approving them.
Additional resources
- See Configuring a three-node cluster for details about deploying three-node clusters in bare metal environments.
- See Approving the certificate signing requests for your machines for more information about approving cluster certificate signing requests after installation.
3.3.4. Networking requirements for user-provisioned infrastructure
All the Red Hat Enterprise Linux CoreOS (RHCOS) machines require networking to be configured in initramfs
during boot to fetch their Ignition config files.
During the initial boot, the machines require an IP address configuration that is set either through a DHCP server or statically by providing the required boot options. After a network connection is established, the machines download their Ignition config files from an HTTP or HTTPS server. The Ignition config files are then used to set the exact state of each machine. The Machine Config Operator completes more changes to the machines, such as the application of new certificates or keys, after installation.
It is recommended to use a DHCP server for long-term management of the cluster machines. Ensure that the DHCP server is configured to provide persistent IP addresses, DNS server information, and hostnames to the cluster machines.
If a DHCP service is not available for your user-provisioned infrastructure, you can instead provide the IP networking configuration and the address of the DNS server to the nodes at RHCOS install time. These can be passed as boot arguments if you are installing from an ISO image. See the Installing RHCOS and starting the OpenShift Container Platform bootstrap process section for more information about static IP provisioning and advanced networking options.
The Kubernetes API server must be able to resolve the node names of the cluster machines. If the API servers and worker nodes are in different zones, you can configure a default DNS search zone to allow the API server to resolve the node names. Another supported approach is to always refer to hosts by their fully-qualified domain names in both the node objects and all DNS requests.
3.3.4.1. Setting the cluster node hostnames through DHCP
On Red Hat Enterprise Linux CoreOS (RHCOS) machines, the hostname is set through NetworkManager. By default, the machines obtain their hostname through DHCP. If the hostname is not provided by DHCP, set statically through kernel arguments, or another method, it is obtained through a reverse DNS lookup. Reverse DNS lookup occurs after the network has been initialized on a node and can take time to resolve. Other system services can start prior to this and detect the hostname as localhost
or similar. You can avoid this by using DHCP to provide the hostname for each cluster node.
Additionally, setting the hostnames through DHCP can bypass any manual DNS record name configuration errors in environments that have a DNS split-horizon implementation.
3.3.4.2. Network connectivity requirements
You must configure the network connectivity between machines to allow OpenShift Container Platform cluster components to communicate. Each machine must be able to resolve the hostnames of all other machines in the cluster.
This section provides details about the ports that are required.
In connected OpenShift Container Platform environments, all nodes are required to have internet access to pull images for platform containers and provide telemetry data to Red Hat.
Protocol | Port | Description |
---|---|---|
ICMP | N/A | Network reachability tests |
TCP |
| Metrics |
|
Host level services, including the node exporter on ports | |
| The default ports that Kubernetes reserves | |
| openshift-sdn | |
UDP |
| VXLAN |
| Geneve | |
|
Host level services, including the node exporter on ports | |
| IPsec IKE packets | |
| IPsec NAT-T packets | |
|
Network Time Protocol (NTP) on UDP port
If an external NTP time server is configured, you must open UDP port | |
TCP/UDP |
| Kubernetes node port |
ESP | N/A | IPsec Encapsulating Security Payload (ESP) |
Protocol | Port | Description |
---|---|---|
TCP |
| Kubernetes API |
Protocol | Port | Description |
---|---|---|
TCP |
| etcd server and peer ports |
NTP configuration for user-provisioned infrastructure
OpenShift Container Platform clusters are configured to use a public Network Time Protocol (NTP) server by default. If you want to use a local enterprise NTP server, or if your cluster is being deployed in a disconnected network, you can configure the cluster to use a specific time server. For more information, see the documentation for Configuring chrony time service.
If a DHCP server provides NTP server information, the chrony time service on the Red Hat Enterprise Linux CoreOS (RHCOS) machines read the information and can sync the clock with the NTP servers.
Additional resources
3.3.5. User-provisioned DNS requirements
In OpenShift Container Platform deployments, DNS name resolution is required for the following components:
- The Kubernetes API
- The OpenShift Container Platform application wildcard
- The bootstrap, control plane, and compute machines
Reverse DNS resolution is also required for the Kubernetes API, the bootstrap machine, the control plane machines, and the compute machines.
DNS A/AAAA or CNAME records are used for name resolution and PTR records are used for reverse name resolution. The reverse records are important because Red Hat Enterprise Linux CoreOS (RHCOS) uses the reverse records to set the hostnames for all the nodes, unless the hostnames are provided by DHCP. Additionally, the reverse records are used to generate the certificate signing requests (CSR) that OpenShift Container Platform needs to operate.
It is recommended to use a DHCP server to provide the hostnames to each cluster node. See the DHCP recommendations for user-provisioned infrastructure section for more information.
The following DNS records are required for a user-provisioned OpenShift Container Platform cluster and they must be in place before installation. In each record, <cluster_name>
is the cluster name and <base_domain>
is the base domain that you specify in the install-config.yaml
file. A complete DNS record takes the form: <component>.<cluster_name>.<base_domain>.
.
Component | Record | Description |
---|---|---|
Kubernetes API |
| A DNS A/AAAA or CNAME record, and a DNS PTR record, to identify the API load balancer. These records must be resolvable by both clients external to the cluster and from all the nodes within the cluster. |
| A DNS A/AAAA or CNAME record, and a DNS PTR record, to internally identify the API load balancer. These records must be resolvable from all the nodes within the cluster. Important The API server must be able to resolve the worker nodes by the hostnames that are recorded in Kubernetes. If the API server cannot resolve the node names, then proxied API calls can fail, and you cannot retrieve logs from pods. | |
Routes |
| A wildcard DNS A/AAAA or CNAME record that refers to the application ingress load balancer. The application ingress load balancer targets the machines that run the Ingress Controller pods. The Ingress Controller pods run on the compute machines by default. These records must be resolvable by both clients external to the cluster and from all the nodes within the cluster.
For example, |
Bootstrap machine |
| A DNS A/AAAA or CNAME record, and a DNS PTR record, to identify the bootstrap machine. These records must be resolvable by the nodes within the cluster. |
Control plane machines |
| DNS A/AAAA or CNAME records and DNS PTR records to identify each machine for the control plane nodes. These records must be resolvable by the nodes within the cluster. |
Compute machines |
| DNS A/AAAA or CNAME records and DNS PTR records to identify each machine for the worker nodes. These records must be resolvable by the nodes within the cluster. |
In OpenShift Container Platform 4.4 and later, you do not need to specify etcd host and SRV records in your DNS configuration.
You can use the dig
command to verify name and reverse name resolution. See the section on Validating DNS resolution for user-provisioned infrastructure for detailed validation steps.
3.3.5.1. Example DNS configuration for user-provisioned clusters
This section provides A and PTR record configuration samples that meet the DNS requirements for deploying OpenShift Container Platform on user-provisioned infrastructure. The samples are not meant to provide advice for choosing one DNS solution over another.
In the examples, the cluster name is ocp4
and the base domain is example.com
.
Example DNS A record configuration for a user-provisioned cluster
The following example is a BIND zone file that shows sample A records for name resolution in a user-provisioned cluster.
Example 3.1. Sample DNS zone database
$TTL 1W @ IN SOA ns1.example.com. root ( 2019070700 ; serial 3H ; refresh (3 hours) 30M ; retry (30 minutes) 2W ; expiry (2 weeks) 1W ) ; minimum (1 week) IN NS ns1.example.com. IN MX 10 smtp.example.com. ; ; ns1.example.com. IN A 192.168.1.5 smtp.example.com. IN A 192.168.1.5 ; helper.example.com. IN A 192.168.1.5 helper.ocp4.example.com. IN A 192.168.1.5 ; api.ocp4.example.com. IN A 192.168.1.5 1 api-int.ocp4.example.com. IN A 192.168.1.5 2 ; *.apps.ocp4.example.com. IN A 192.168.1.5 3 ; bootstrap.ocp4.example.com. IN A 192.168.1.96 4 ; control-plane0.ocp4.example.com. IN A 192.168.1.97 5 control-plane1.ocp4.example.com. IN A 192.168.1.98 6 control-plane2.ocp4.example.com. IN A 192.168.1.99 7 ; compute0.ocp4.example.com. IN A 192.168.1.11 8 compute1.ocp4.example.com. IN A 192.168.1.7 9 ; ;EOF
- 1
- Provides name resolution for the Kubernetes API. The record refers to the IP address of the API load balancer.
- 2
- Provides name resolution for the Kubernetes API. The record refers to the IP address of the API load balancer and is used for internal cluster communications.
- 3
- Provides name resolution for the wildcard routes. The record refers to the IP address of the application ingress load balancer. The application ingress load balancer targets the machines that run the Ingress Controller pods. The Ingress Controller pods run on the compute machines by default.Note
In the example, the same load balancer is used for the Kubernetes API and application ingress traffic. In production scenarios, you can deploy the API and application ingress load balancers separately so that you can scale the load balancer infrastructure for each in isolation.
- 4
- Provides name resolution for the bootstrap machine.
- 5 6 7
- Provides name resolution for the control plane machines.
- 8 9
- Provides name resolution for the compute machines.
Example DNS PTR record configuration for a user-provisioned cluster
The following example BIND zone file shows sample PTR records for reverse name resolution in a user-provisioned cluster.
Example 3.2. Sample DNS zone database for reverse records
$TTL 1W @ IN SOA ns1.example.com. root ( 2019070700 ; serial 3H ; refresh (3 hours) 30M ; retry (30 minutes) 2W ; expiry (2 weeks) 1W ) ; minimum (1 week) IN NS ns1.example.com. ; 5.1.168.192.in-addr.arpa. IN PTR api.ocp4.example.com. 1 5.1.168.192.in-addr.arpa. IN PTR api-int.ocp4.example.com. 2 ; 96.1.168.192.in-addr.arpa. IN PTR bootstrap.ocp4.example.com. 3 ; 97.1.168.192.in-addr.arpa. IN PTR control-plane0.ocp4.example.com. 4 98.1.168.192.in-addr.arpa. IN PTR control-plane1.ocp4.example.com. 5 99.1.168.192.in-addr.arpa. IN PTR control-plane2.ocp4.example.com. 6 ; 11.1.168.192.in-addr.arpa. IN PTR compute0.ocp4.example.com. 7 7.1.168.192.in-addr.arpa. IN PTR compute1.ocp4.example.com. 8 ; ;EOF
- 1
- Provides reverse DNS resolution for the Kubernetes API. The PTR record refers to the record name of the API load balancer.
- 2
- Provides reverse DNS resolution for the Kubernetes API. The PTR record refers to the record name of the API load balancer and is used for internal cluster communications.
- 3
- Provides reverse DNS resolution for the bootstrap machine.
- 4 5 6
- Provides reverse DNS resolution for the control plane machines.
- 7 8
- Provides reverse DNS resolution for the compute machines.
A PTR record is not required for the OpenShift Container Platform application wildcard.
3.3.6. Load balancing requirements for user-provisioned infrastructure
Before you install OpenShift Container Platform, you must provision the API and application Ingress load balancing infrastructure. In production scenarios, you can deploy the API and application Ingress load balancers separately so that you can scale the load balancer infrastructure for each in isolation.
If you want to deploy the API and application Ingress load balancers with a Red Hat Enterprise Linux (RHEL) instance, you must purchase the RHEL subscription separately.
The load balancing infrastructure must meet the following requirements:
API load balancer: Provides a common endpoint for users, both human and machine, to interact with and configure the platform. Configure the following conditions:
- Layer 4 load balancing only. This can be referred to as Raw TCP or SSL Passthrough mode.
- A stateless load balancing algorithm. The options vary based on the load balancer implementation.
ImportantDo not configure session persistence for an API load balancer. Configuring session persistence for a Kubernetes API server might cause performance issues from excess application traffic for your OpenShift Container Platform cluster and the Kubernetes API that runs inside the cluster.
Configure the following ports on both the front and back of the load balancers:
Table 3.7. API load balancer Port Back-end machines (pool members) Internal External Description 6443
Bootstrap and control plane. You remove the bootstrap machine from the load balancer after the bootstrap machine initializes the cluster control plane. You must configure the
/readyz
endpoint for the API server health check probe.X
X
Kubernetes API server
22623
Bootstrap and control plane. You remove the bootstrap machine from the load balancer after the bootstrap machine initializes the cluster control plane.
X
Machine config server
NoteThe load balancer must be configured to take a maximum of 30 seconds from the time the API server turns off the
/readyz
endpoint to the removal of the API server instance from the pool. Within the time frame after/readyz
returns an error or becomes healthy, the endpoint must have been removed or added. Probing every 5 or 10 seconds, with two successful requests to become healthy and three to become unhealthy, are well-tested values.Application Ingress load balancer: Provides an ingress point for application traffic flowing in from outside the cluster. A working configuration for the Ingress router is required for an OpenShift Container Platform cluster.
Configure the following conditions:
- Layer 4 load balancing only. This can be referred to as Raw TCP or SSL Passthrough mode.
- A connection-based or session-based persistence is recommended, based on the options available and types of applications that will be hosted on the platform.
TipIf the true IP address of the client can be seen by the application Ingress load balancer, enabling source IP-based session persistence can improve performance for applications that use end-to-end TLS encryption.
Configure the following ports on both the front and back of the load balancers:
Table 3.8. Application Ingress load balancer Port Back-end machines (pool members) Internal External Description 443
The machines that run the Ingress Controller pods, compute, or worker, by default.
X
X
HTTPS traffic
80
The machines that run the Ingress Controller pods, compute, or worker, by default.
X
X
HTTP traffic
NoteIf you are deploying a three-node cluster with zero compute nodes, the Ingress Controller pods run on the control plane nodes. In three-node cluster deployments, you must configure your application Ingress load balancer to route HTTP and HTTPS traffic to the control plane nodes.
3.3.6.1. Example load balancer configuration for user-provisioned clusters
This section provides an example API and application Ingress load balancer configuration that meets the load balancing requirements for user-provisioned clusters. The sample is an /etc/haproxy/haproxy.cfg
configuration for an HAProxy load balancer. The example is not meant to provide advice for choosing one load balancing solution over another.
In the example, the same load balancer is used for the Kubernetes API and application ingress traffic. In production scenarios, you can deploy the API and application ingress load balancers separately so that you can scale the load balancer infrastructure for each in isolation.
If you are using HAProxy as a load balancer and SELinux is set to enforcing
, you must ensure that the HAProxy service can bind to the configured TCP port by running setsebool -P haproxy_connect_any=1
.
Example 3.3. Sample API and application Ingress load balancer configuration
global log 127.0.0.1 local2 pidfile /var/run/haproxy.pid maxconn 4000 daemon defaults mode http log global option dontlognull option http-server-close option redispatch retries 3 timeout http-request 10s timeout queue 1m timeout connect 10s timeout client 1m timeout server 1m timeout http-keep-alive 10s timeout check 10s maxconn 3000 listen api-server-6443 1 bind *:6443 mode tcp option httpchk GET /readyz HTTP/1.0 option log-health-checks balance roundrobin server bootstrap bootstrap.ocp4.example.com:6443 verify none check check-ssl inter 10s fall 2 rise 3 backup 2 server master0 master0.ocp4.example.com:6443 weight 1 verify none check check-ssl inter 10s fall 2 rise 3 server master1 master1.ocp4.example.com:6443 weight 1 verify none check check-ssl inter 10s fall 2 rise 3 server master2 master2.ocp4.example.com:6443 weight 1 verify none check check-ssl inter 10s fall 2 rise 3 listen machine-config-server-22623 3 bind *:22623 mode tcp server bootstrap bootstrap.ocp4.example.com:22623 check inter 1s backup 4 server master0 master0.ocp4.example.com:22623 check inter 1s server master1 master1.ocp4.example.com:22623 check inter 1s server master2 master2.ocp4.example.com:22623 check inter 1s listen ingress-router-443 5 bind *:443 mode tcp balance source server worker0 worker0.ocp4.example.com:443 check inter 1s server worker1 worker1.ocp4.example.com:443 check inter 1s listen ingress-router-80 6 bind *:80 mode tcp balance source server worker0 worker0.ocp4.example.com:80 check inter 1s server worker1 worker1.ocp4.example.com:80 check inter 1s
- 1
- Port
6443
handles the Kubernetes API traffic and points to the control plane machines. - 2 4
- The bootstrap entries must be in place before the OpenShift Container Platform cluster installation and they must be removed after the bootstrap process is complete.
- 3
- Port
22623
handles the machine config server traffic and points to the control plane machines. - 5
- Port
443
handles the HTTPS traffic and points to the machines that run the Ingress Controller pods. The Ingress Controller pods run on the compute machines by default. - 6
- Port
80
handles the HTTP traffic and points to the machines that run the Ingress Controller pods. The Ingress Controller pods run on the compute machines by default.NoteIf you are deploying a three-node cluster with zero compute nodes, the Ingress Controller pods run on the control plane nodes. In three-node cluster deployments, you must configure your application Ingress load balancer to route HTTP and HTTPS traffic to the control plane nodes.
If you are using HAProxy as a load balancer, you can check that the haproxy
process is listening on ports 6443
, 22623
, 443
, and 80
by running netstat -nltupe
on the HAProxy node.
3.4. Preparing the user-provisioned infrastructure
Before you install OpenShift Container Platform on user-provisioned infrastructure, you must prepare the underlying infrastructure.
This section provides details about the high-level steps required to set up your cluster infrastructure in preparation for an OpenShift Container Platform installation. This includes configuring IP networking and network connectivity for your cluster nodes, enabling the required ports through your firewall, and setting up the required DNS and load balancing infrastructure.
After preparation, your cluster infrastructure must meet the requirements outlined in the Requirements for a cluster with user-provisioned infrastructure section.
Prerequisites
- You have reviewed the OpenShift Container Platform 4.x Tested Integrations page.
- You have reviewed the infrastructure requirements detailed in the Requirements for a cluster with user-provisioned infrastructure section.
Procedure
If you are using DHCP to provide the IP networking configuration to your cluster nodes, configure your DHCP service.
- Add persistent IP addresses for the nodes to your DHCP server configuration. In your configuration, match the MAC address of the relevant network interface to the intended IP address for each node.
When you use DHCP to configure IP addressing for the cluster machines, the machines also obtain the DNS server information through DHCP. Define the persistent DNS server address that is used by the cluster nodes through your DHCP server configuration.
NoteIf you are not using a DHCP service, you must provide the IP networking configuration and the address of the DNS server to the nodes at RHCOS install time. These can be passed as boot arguments if you are installing from an ISO image. See the Installing RHCOS and starting the OpenShift Container Platform bootstrap process section for more information about static IP provisioning and advanced networking options.
Define the hostnames of your cluster nodes in your DHCP server configuration. See the Setting the cluster node hostnames through DHCP section for details about hostname considerations.
NoteIf you are not using a DHCP service, the cluster nodes obtain their hostname through a reverse DNS lookup.
- Ensure that your network infrastructure provides the required network connectivity between the cluster components. See the Networking requirements for user-provisioned infrastructure section for details about the requirements.
Configure your firewall to enable the ports required for the OpenShift Container Platform cluster components to communicate. See Networking requirements for user-provisioned infrastructure section for details about the ports that are required.
ImportantBy default, port
1936
is accessible for an OpenShift Container Platform cluster, because each control plane node needs access to this port.Avoid using the Ingress load balancer to expose this port, because doing so might result in the exposure of sensitive information, such as statistics and metrics, related to Ingress Controllers.
Setup the required DNS infrastructure for your cluster.
- Configure DNS name resolution for the Kubernetes API, the application wildcard, the bootstrap machine, the control plane machines, and the compute machines.
Configure reverse DNS resolution for the Kubernetes API, the bootstrap machine, the control plane machines, and the compute machines.
See the User-provisioned DNS requirements section for more information about the OpenShift Container Platform DNS requirements.
Validate your DNS configuration.
- From your installation node, run DNS lookups against the record names of the Kubernetes API, the wildcard routes, and the cluster nodes. Validate that the IP addresses in the responses correspond to the correct components.
From your installation node, run reverse DNS lookups against the IP addresses of the load balancer and the cluster nodes. Validate that the record names in the responses correspond to the correct components.
See the Validating DNS resolution for user-provisioned infrastructure section for detailed DNS validation steps.
- Provision the required API and application ingress load balancing infrastructure. See the Load balancing requirements for user-provisioned infrastructure section for more information about the requirements.
Some load balancing solutions require the DNS name resolution for the cluster nodes to be in place before the load balancing is initialized.
Additional resources
- Requirements for a cluster with user-provisioned infrastructure
- Installing RHCOS and starting the OpenShift Container Platform bootstrap process
- Setting the cluster node hostnames through DHCP
- Advanced RHCOS installation configuration
- Networking requirements for user-provisioned infrastructure
- User-provisioned DNS requirements
- Validating DNS resolution for user-provisioned infrastructure
- Load balancing requirements for user-provisioned infrastructure
3.5. Validating DNS resolution for user-provisioned infrastructure
You can validate your DNS configuration before installing OpenShift Container Platform on user-provisioned infrastructure.
The validation steps detailed in this section must succeed before you install your cluster.
Prerequisites
- You have configured the required DNS records for your user-provisioned infrastructure.
Procedure
From your installation node, run DNS lookups against the record names of the Kubernetes API, the wildcard routes, and the cluster nodes. Validate that the IP addresses contained in the responses correspond to the correct components.
Perform a lookup against the Kubernetes API record name. Check that the result points to the IP address of the API load balancer:
$ dig +noall +answer @<nameserver_ip> api.<cluster_name>.<base_domain> 1
- 1
- Replace
<nameserver_ip>
with the IP address of the nameserver,<cluster_name>
with your cluster name, and<base_domain>
with your base domain name.
Example output
api.ocp4.example.com. 604800 IN A 192.168.1.5
Perform a lookup against the Kubernetes internal API record name. Check that the result points to the IP address of the API load balancer:
$ dig +noall +answer @<nameserver_ip> api-int.<cluster_name>.<base_domain>
Example output
api-int.ocp4.example.com. 604800 IN A 192.168.1.5
Test an example
*.apps.<cluster_name>.<base_domain>
DNS wildcard lookup. All of the application wildcard lookups must resolve to the IP address of the application ingress load balancer:$ dig +noall +answer @<nameserver_ip> random.apps.<cluster_name>.<base_domain>
Example output
random.apps.ocp4.example.com. 604800 IN A 192.168.1.5
NoteIn the example outputs, the same load balancer is used for the Kubernetes API and application ingress traffic. In production scenarios, you can deploy the API and application ingress load balancers separately so that you can scale the load balancer infrastructure for each in isolation.
You can replace
random
with another wildcard value. For example, you can query the route to the OpenShift Container Platform console:$ dig +noall +answer @<nameserver_ip> console-openshift-console.apps.<cluster_name>.<base_domain>
Example output
console-openshift-console.apps.ocp4.example.com. 604800 IN A 192.168.1.5
Run a lookup against the bootstrap DNS record name. Check that the result points to the IP address of the bootstrap node:
$ dig +noall +answer @<nameserver_ip> bootstrap.<cluster_name>.<base_domain>
Example output
bootstrap.ocp4.example.com. 604800 IN A 192.168.1.96
- Use this method to perform lookups against the DNS record names for the control plane and compute nodes. Check that the results correspond to the IP addresses of each node.
From your installation node, run reverse DNS lookups against the IP addresses of the load balancer and the cluster nodes. Validate that the record names contained in the responses correspond to the correct components.
Perform a reverse lookup against the IP address of the API load balancer. Check that the response includes the record names for the Kubernetes API and the Kubernetes internal API:
$ dig +noall +answer @<nameserver_ip> -x 192.168.1.5
Example output
5.1.168.192.in-addr.arpa. 604800 IN PTR api-int.ocp4.example.com. 1 5.1.168.192.in-addr.arpa. 604800 IN PTR api.ocp4.example.com. 2
NoteA PTR record is not required for the OpenShift Container Platform application wildcard. No validation step is needed for reverse DNS resolution against the IP address of the application ingress load balancer.
Perform a reverse lookup against the IP address of the bootstrap node. Check that the result points to the DNS record name of the bootstrap node:
$ dig +noall +answer @<nameserver_ip> -x 192.168.1.96
Example output
96.1.168.192.in-addr.arpa. 604800 IN PTR bootstrap.ocp4.example.com.
- Use this method to perform reverse lookups against the IP addresses for the control plane and compute nodes. Check that the results correspond to the DNS record names of each node.
3.6. Generating a key pair for cluster node SSH access
During an OpenShift Container Platform installation, you can provide an SSH public key to the installation program. The key is passed to the Red Hat Enterprise Linux CoreOS (RHCOS) nodes through their Ignition config files and is used to authenticate SSH access to the nodes. The key is added to the ~/.ssh/authorized_keys
list for the core
user on each node, which enables password-less authentication.
After the key is passed to the nodes, you can use the key pair to SSH in to the RHCOS nodes as the user core
. To access the nodes through SSH, the private key identity must be managed by SSH for your local user.
If you want to SSH in to your cluster nodes to perform installation debugging or disaster recovery, you must provide the SSH public key during the installation process. The ./openshift-install gather
command also requires the SSH public key to be in place on the cluster nodes.
Do not skip this procedure in production environments, where disaster recovery and debugging is required.
You must use a local key, not one that you configured with platform-specific approaches such as AWS key pairs.
Procedure
If you do not have an existing SSH key pair on your local machine to use for authentication onto your cluster nodes, create one. For example, on a computer that uses a Linux operating system, run the following command:
$ ssh-keygen -t ed25519 -N '' -f <path>/<file_name> 1
- 1
- Specify the path and file name, such as
~/.ssh/id_ed25519
, of the new SSH key. If you have an existing key pair, ensure your public key is in the your~/.ssh
directory.
View the public SSH key:
$ cat <path>/<file_name>.pub
For example, run the following to view the
~/.ssh/id_ed25519.pub
public key:$ cat ~/.ssh/id_ed25519.pub
Add the SSH private key identity to the SSH agent for your local user, if it has not already been added. SSH agent management of the key is required for password-less SSH authentication onto your cluster nodes, or if you want to use the
./openshift-install gather
command.NoteOn some distributions, default SSH private key identities such as
~/.ssh/id_rsa
and~/.ssh/id_dsa
are managed automatically.If the
ssh-agent
process is not already running for your local user, start it as a background task:$ eval "$(ssh-agent -s)"
Example output
Agent pid 31874
Add your SSH private key to the
ssh-agent
:$ ssh-add <path>/<file_name> 1
- 1
- Specify the path and file name for your SSH private key, such as
~/.ssh/id_ed25519
Example output
Identity added: /home/<you>/<path>/<file_name> (<computer_name>)
Next steps
- When you install OpenShift Container Platform, provide the SSH public key to the installation program.
Additional resources
3.7. Obtaining the installation program
Before you install OpenShift Container Platform, download the installation file on the host you are using for installation.
Prerequisites
- You have a computer that runs Linux or macOS, with 500 MB of local disk space.
Procedure
- Access the Infrastructure Provider page on the OpenShift Cluster Manager site. If you have a Red Hat account, log in with your credentials. If you do not, create an account.
- Select your infrastructure provider.
Navigate to the page for your installation type, download the installation program that corresponds with your host operating system and architecture, and place the file in the directory where you will store the installation configuration files.
ImportantThe installation program creates several files on the computer that you use to install your cluster. You must keep the installation program and the files that the installation program creates after you finish installing the cluster. Both files are required to delete the cluster.
ImportantDeleting the files created by the installation program does not remove your cluster, even if the cluster failed during installation. To remove your cluster, complete the OpenShift Container Platform uninstallation procedures for your specific cloud provider.
Extract the installation program. For example, on a computer that uses a Linux operating system, run the following command:
$ tar -xvf openshift-install-linux.tar.gz
- Download your installation pull secret from the Red Hat OpenShift Cluster Manager. This pull secret allows you to authenticate with the services that are provided by the included authorities, including Quay.io, which serves the container images for OpenShift Container Platform components.
3.8. Installing the OpenShift CLI by downloading the binary
You can install the OpenShift CLI (oc
) to interact with OpenShift Container Platform from a command-line interface. You can install oc
on Linux, Windows, or macOS.
If you installed an earlier version of oc
, you cannot use it to complete all of the commands in OpenShift Container Platform 4.13. Download and install the new version of oc
.
Installing the OpenShift CLI on Linux
You can install the OpenShift CLI (oc
) binary on Linux by using the following procedure.
Procedure
- Navigate to the OpenShift Container Platform downloads page on the Red Hat Customer Portal.
- Select the architecture from the Product Variant drop-down list.
- Select the appropriate version from the Version drop-down list.
- Click Download Now next to the OpenShift v4.13 Linux Client entry and save the file.
Unpack the archive:
$ tar xvf <file>
Place the
oc
binary in a directory that is on yourPATH
.To check your
PATH
, execute the following command:$ echo $PATH
Verification
After you install the OpenShift CLI, it is available using the
oc
command:$ oc <command>
Installing the OpenShift CLI on Windows
You can install the OpenShift CLI (oc
) binary on Windows by using the following procedure.
Procedure
- Navigate to the OpenShift Container Platform downloads page on the Red Hat Customer Portal.
- Select the appropriate version from the Version drop-down list.
- Click Download Now next to the OpenShift v4.13 Windows Client entry and save the file.
- Unzip the archive with a ZIP program.
Move the
oc
binary to a directory that is on yourPATH
.To check your
PATH
, open the command prompt and execute the following command:C:\> path
Verification
After you install the OpenShift CLI, it is available using the
oc
command:C:\> oc <command>
Installing the OpenShift CLI on macOS
You can install the OpenShift CLI (oc
) binary on macOS by using the following procedure.
Procedure
- Navigate to the OpenShift Container Platform downloads page on the Red Hat Customer Portal.
- Select the appropriate version from the Version drop-down list.
Click Download Now next to the OpenShift v4.13 macOS Client entry and save the file.
NoteFor macOS arm64, choose the OpenShift v4.13 macOS arm64 Client entry.
- Unpack and unzip the archive.
Move the
oc
binary to a directory on your PATH.To check your
PATH
, open a terminal and execute the following command:$ echo $PATH
Verification
After you install the OpenShift CLI, it is available using the
oc
command:$ oc <command>
3.9. Manually creating the installation configuration file
Installing the cluster requires that you manually create the installation configuration file.
Prerequisites
- You have an SSH public key on your local machine to provide to the installation program. The key will be used for SSH authentication onto your cluster nodes for debugging and disaster recovery.
- You have obtained the OpenShift Container Platform installation program and the pull secret for your cluster.
Procedure
Create an installation directory to store your required installation assets in:
$ mkdir <installation_directory>
ImportantYou must create a directory. Some installation assets, like bootstrap X.509 certificates have short expiration intervals, so you must not reuse an installation directory. If you want to reuse individual files from another cluster installation, you can copy them into your directory. However, the file names for the installation assets might change between releases. Use caution when copying installation files from an earlier OpenShift Container Platform version.
Customize the sample
install-config.yaml
file template that is provided and save it in the<installation_directory>
.NoteYou must name this configuration file
install-config.yaml
.Back up the
install-config.yaml
file so that you can use it to install multiple clusters.ImportantThe
install-config.yaml
file is consumed during the next step of the installation process. You must back it up now.
3.9.1. Installation configuration parameters
Before you deploy an OpenShift Container Platform cluster, you provide a customized install-config.yaml
installation configuration file that describes the details for your environment.
After installation, you cannot modify these parameters in the install-config.yaml
file.
3.9.1.1. Required configuration parameters
Required installation configuration parameters are described in the following table:
Parameter | Description | Values |
---|---|---|
|
The API version for the | String |
|
The base domain of your cloud provider. The base domain is used to create routes to your OpenShift Container Platform cluster components. The full DNS name for your cluster is a combination of the |
A fully-qualified domain or subdomain name, such as |
|
Kubernetes resource | Object |
|
The name of the cluster. DNS records for the cluster are all subdomains of |
String of lowercase letters and hyphens ( |
|
The configuration for the specific platform upon which to perform the installation: | Object |
| Get a pull secret from the Red Hat OpenShift Cluster Manager to authenticate downloading container images for OpenShift Container Platform components from services such as Quay.io. |
{ "auths":{ "cloud.openshift.com":{ "auth":"b3Blb=", "email":"you@example.com" }, "quay.io":{ "auth":"b3Blb=", "email":"you@example.com" } } } |
3.9.1.2. Network configuration parameters
You can customize your installation configuration based on the requirements of your existing network infrastructure. For example, you can expand the IP address block for the cluster network or provide different IP address blocks than the defaults.
- If you use the Red Hat OpenShift Networking OVN-Kubernetes network plugin, both IPv4 and IPv6 address families are supported.
- If you use the Red Hat OpenShift Networking OpenShift SDN network plugin, only the IPv4 address family is supported.
If you configure your cluster to use both IP address families, review the following requirements:
- Both IP families must use the same network interface for the default gateway.
- Both IP families must have the default gateway.
- You must specify IPv4 and IPv6 addresses in the same order for all network configuration parameters. For example, in the following configuration IPv4 addresses are listed before IPv6 addresses.
networking: clusterNetwork: - cidr: 10.128.0.0/14 hostPrefix: 23 - cidr: fd00:10:128::/56 hostPrefix: 64 serviceNetwork: - 172.30.0.0/16 - fd00:172:16::/112
Globalnet is not supported with Red Hat OpenShift Data Foundation disaster recovery solutions. For regional disaster recovery scenarios, ensure that you use a nonoverlapping range of private IP addresses for the cluster and service networks in each cluster.
Parameter | Description | Values |
---|---|---|
| The configuration for the cluster network. | Object Note
You cannot modify parameters specified by the |
| The Red Hat OpenShift Networking network plugin to install. |
Either |
| The IP address blocks for pods.
The default value is If you specify multiple IP address blocks, the blocks must not overlap. | An array of objects. For example: networking: clusterNetwork: - cidr: 10.128.0.0/14 hostPrefix: 23 - cidr: fd01::/48 hostPrefix: 64 |
|
Required if you use If you use the OpenShift SDN network plugin, specify an IPv4 network. If you use the OVN-Kubernetes network plugin, you can specify IPv4 and IPv6 networks. |
An IP address block in Classless Inter-Domain Routing (CIDR) notation. The prefix length for an IPv4 block is between |
|
The subnet prefix length to assign to each individual node. For example, if | A subnet prefix.
For an IPv4 network the default value is |
|
The IP address block for services. The default value is The OpenShift SDN and OVN-Kubernetes network plugins support only a single IP address block for the service network. If you use the OVN-Kubernetes network plugin, you can specify an IP address block for both of the IPv4 and IPv6 address families. | An array with an IP address block in CIDR format. For example: networking: serviceNetwork: - 172.30.0.0/16 - fd02::/112 |
| The IP address blocks for machines. If you specify multiple IP address blocks, the blocks must not overlap. | An array of objects. For example: networking: machineNetwork: - cidr: 10.0.0.0/16 |
|
Required if you use | An IP network block in CIDR notation.
For example, Note
Set the |
3.9.1.3. Optional configuration parameters
Optional installation configuration parameters are described in the following table:
Parameter | Description | Values |
---|---|---|
| A PEM-encoded X.509 certificate bundle that is added to the nodes' trusted certificate store. This trust bundle may also be used when a proxy has been configured. | String |
| Controls the installation of optional core cluster components. You can reduce the footprint of your OpenShift Container Platform cluster by disabling optional components. For more information, see the "Cluster capabilities" page in Installing. | String array |
|
Selects an initial set of optional capabilities to enable. Valid values are | String |
|
Extends the set of optional capabilities beyond what you specify in | String array |
| Enables workload partitioning, which isolates OpenShift Container Platform services, cluster management workloads, and infrastructure pods to run on a reserved set of CPUs. Workload partitioning can only be enabled during installation and cannot be disabled after installation. While this field enables workload partitioning, it does not configure workloads to use specific CPUs. For more information, see the Workload partitioning page in the Scalability and Performance section. |
|
| The configuration for the machines that comprise the compute nodes. |
Array of |
|
Determines the instruction set architecture of the machines in the pool. Currently, clusters with varied architectures are not supported. All pools must specify the same architecture. Valid values are | String |
compute: hyperthreading: |
Whether to enable or disable simultaneous multithreading, or Important If you disable simultaneous multithreading, ensure that your capacity planning accounts for the dramatically decreased machine performance. |
|
|
Required if you use |
|
|
Required if you use |
|
| The number of compute machines, which are also known as worker machines, to provision. |
A positive integer greater than or equal to |
| Enables the cluster for a feature set. A feature set is a collection of OpenShift Container Platform features that are not enabled by default. For more information about enabling a feature set during installation, see "Enabling features using feature gates". |
String. The name of the feature set to enable, such as |
| The configuration for the machines that comprise the control plane. |
Array of |
|
Determines the instruction set architecture of the machines in the pool. Currently, clusters with varied architectures are not supported. All pools must specify the same architecture. Valid values are | String |
controlPlane: hyperthreading: |
Whether to enable or disable simultaneous multithreading, or Important If you disable simultaneous multithreading, ensure that your capacity planning accounts for the dramatically decreased machine performance. |
|
|
Required if you use |
|
|
Required if you use |
|
| The number of control plane machines to provision. |
The only supported value is |
| The Cloud Credential Operator (CCO) mode. If no mode is specified, the CCO dynamically tries to determine the capabilities of the provided credentials, with a preference for mint mode on the platforms where multiple modes are supported. Note Not all CCO modes are supported for all cloud providers. For more information about CCO modes, see the Cloud Credential Operator entry in the Cluster Operators reference content. Note
If your AWS account has service control policies (SCP) enabled, you must configure the |
|
| Sources and repositories for the release-image content. |
Array of objects. Includes a |
|
Required if you use | String |
| Specify one or more repositories that may also contain the same images. | Array of strings |
| How to publish or expose the user-facing endpoints of your cluster, such as the Kubernetes API, OpenShift routes. |
Setting this field to Important
If the value of the field is set to |
| The SSH key to authenticate access to your cluster machines. Note
For production OpenShift Container Platform clusters on which you want to perform installation debugging or disaster recovery, specify an SSH key that your |
For example, |
- Not all CCO modes are supported for all cloud providers. For more information about CCO modes, see the "Managing cloud provider credentials" entry in the Authentication and authorization content.
3.9.2. Sample install-config.yaml file for bare metal
You can customize the install-config.yaml
file to specify more details about your OpenShift Container Platform cluster’s platform or modify the values of the required parameters.
apiVersion: v1 baseDomain: example.com 1 compute: 2 - hyperthreading: Enabled 3 name: worker replicas: 0 4 controlPlane: 5 hyperthreading: Enabled 6 name: master replicas: 3 7 metadata: name: test 8 networking: clusterNetwork: - cidr: 10.128.0.0/14 9 hostPrefix: 23 10 networkType: OVNKubernetes 11 serviceNetwork: 12 - 172.30.0.0/16 platform: none: {} 13 fips: false 14 pullSecret: '{"auths": ...}' 15 sshKey: 'ssh-ed25519 AAAA...' 16
- 1
- The base domain of the cluster. All DNS records must be sub-domains of this base and include the cluster name.
- 2 5
- The
controlPlane
section is a single mapping, but thecompute
section is a sequence of mappings. To meet the requirements of the different data structures, the first line of thecompute
section must begin with a hyphen,-
, and the first line of thecontrolPlane
section must not. Only one control plane pool is used. - 3 6
- Specifies whether to enable or disable simultaneous multithreading (SMT), or hyperthreading. By default, SMT is enabled to increase the performance of the cores in your machines. You can disable it by setting the parameter value to
Disabled
. If you disable SMT, you must disable it in all cluster machines; this includes both control plane and compute machines.NoteSimultaneous multithreading (SMT) is enabled by default. If SMT is not enabled in your BIOS settings, the
hyperthreading
parameter has no effect.ImportantIf you disable
hyperthreading
, whether in the BIOS or in theinstall-config.yaml
file, ensure that your capacity planning accounts for the dramatically decreased machine performance. - 4
- You must set this value to
0
when you install OpenShift Container Platform on user-provisioned infrastructure. In installer-provisioned installations, the parameter controls the number of compute machines that the cluster creates and manages for you. In user-provisioned installations, you must manually deploy the compute machines before you finish installing the cluster.NoteIf you are installing a three-node cluster, do not deploy any compute machines when you install the Red Hat Enterprise Linux CoreOS (RHCOS) machines.
- 7
- The number of control plane machines that you add to the cluster. Because the cluster uses these values as the number of etcd endpoints in the cluster, the value must match the number of control plane machines that you deploy.
- 8
- The cluster name that you specified in your DNS records.
- 9
- A block of IP addresses from which pod IP addresses are allocated. This block must not overlap with existing physical networks. These IP addresses are used for the pod network. If you need to access the pods from an external network, you must configure load balancers and routers to manage the traffic.Note
Class E CIDR range is reserved for a future use. To use the Class E CIDR range, you must ensure your networking environment accepts the IP addresses within the Class E CIDR range.
- 10
- The subnet prefix length to assign to each individual node. For example, if
hostPrefix
is set to23
, then each node is assigned a/23
subnet out of the givencidr
, which allows for 510 (2^(32 - 23) - 2) pod IP addresses. If you are required to provide access to nodes from an external network, configure load balancers and routers to manage the traffic. - 11
- The cluster network plugin to install. The supported values are
OVNKubernetes
andOpenShiftSDN
. The default value isOVNKubernetes
. - 12
- The IP address pool to use for service IP addresses. You can enter only one IP address pool. This block must not overlap with existing physical networks. If you need to access the services from an external network, configure load balancers and routers to manage the traffic.
- 13
- You must set the platform to
none
. You cannot provide additional platform configuration variables for your platform.ImportantClusters that are installed with the platform type
none
are unable to use some features, such as managing compute machines with the Machine API. This limitation applies even if the compute machines that are attached to the cluster are installed on a platform that would normally support the feature. This parameter cannot be changed after installation. - 14
- Whether to enable or disable FIPS mode. By default, FIPS mode is not enabled.Important
OpenShift Container Platform 4.13 is based on Red Hat Enterprise Linux (RHEL) 9.2. RHEL 9.2 cryptographic modules have not yet been submitted for FIPS validation. For more information, see "About this release" in the 4.13 OpenShift Container Platform Release Notes.
- 15
- The pull secret from the Red Hat OpenShift Cluster Manager. This pull secret allows you to authenticate with the services that are provided by the included authorities, including Quay.io, which serves the container images for OpenShift Container Platform components.
- 16
- The SSH public key for the
core
user in Red Hat Enterprise Linux CoreOS (RHCOS).NoteFor production OpenShift Container Platform clusters on which you want to perform installation debugging or disaster recovery, specify an SSH key that your
ssh-agent
process uses.
Additional resources
- See Load balancing requirements for user-provisioned infrastructure for more information on the API and application ingress load balancing requirements.
3.10. Network configuration phases
There are two phases prior to OpenShift Container Platform installation where you can customize the network configuration.
- Phase 1
You can customize the following network-related fields in the
install-config.yaml
file before you create the manifest files:-
networking.networkType
-
networking.clusterNetwork
-
networking.serviceNetwork
networking.machineNetwork
For more information on these fields, refer to Installation configuration parameters.
NoteSet the
networking.machineNetwork
to match the CIDR that the preferred NIC resides in.ImportantThe CIDR range
172.17.0.0/16
is reserved by libVirt. You cannot use this range or any range that overlaps with this range for any networks in your cluster.
-
- Phase 2
-
After creating the manifest files by running
openshift-install create manifests
, you can define a customized Cluster Network Operator manifest with only the fields you want to modify. You can use the manifest to specify advanced network configuration.
You cannot override the values specified in phase 1 in the install-config.yaml
file during phase 2. However, you can further customize the network plugin during phase 2.
3.11. Specifying advanced network configuration
You can use advanced network configuration for your network plugin to integrate your cluster into your existing network environment. You can specify advanced network configuration only before you install the cluster.
Customizing your network configuration by modifying the OpenShift Container Platform manifest files created by the installation program is not supported. Applying a manifest file that you create, as in the following procedure, is supported.
Prerequisites
-
You have created the
install-config.yaml
file and completed any modifications to it.
Procedure
Change to the directory that contains the installation program and create the manifests:
$ ./openshift-install create manifests --dir <installation_directory> 1
- 1
<installation_directory>
specifies the name of the directory that contains theinstall-config.yaml
file for your cluster.
Create a stub manifest file for the advanced network configuration that is named
cluster-network-03-config.yml
in the<installation_directory>/manifests/
directory:apiVersion: operator.openshift.io/v1 kind: Network metadata: name: cluster spec:
Specify the advanced network configuration for your cluster in the
cluster-network-03-config.yml
file, such as in the following examples:Specify a different VXLAN port for the OpenShift SDN network provider
apiVersion: operator.openshift.io/v1 kind: Network metadata: name: cluster spec: defaultNetwork: openshiftSDNConfig: vxlanPort: 4800
Enable IPsec for the OVN-Kubernetes network provider
apiVersion: operator.openshift.io/v1 kind: Network metadata: name: cluster spec: defaultNetwork: ovnKubernetesConfig: ipsecConfig: {}
-
Optional: Back up the
manifests/cluster-network-03-config.yml
file. The installation program consumes themanifests/
directory when you create the Ignition config files.
3.12. Cluster Network Operator configuration
The configuration for the cluster network is specified as part of the Cluster Network Operator (CNO) configuration and stored in a custom resource (CR) object that is named cluster
. The CR specifies the fields for the Network
API in the operator.openshift.io
API group.
The CNO configuration inherits the following fields during cluster installation from the Network
API in the Network.config.openshift.io
API group and these fields cannot be changed:
clusterNetwork
- IP address pools from which pod IP addresses are allocated.
serviceNetwork
- IP address pool for services.
defaultNetwork.type
- Cluster network plugin, such as OpenShift SDN or OVN-Kubernetes.
You can specify the cluster network plugin configuration for your cluster by setting the fields for the defaultNetwork
object in the CNO object named cluster
.
3.12.1. Cluster Network Operator configuration object
The fields for the Cluster Network Operator (CNO) are described in the following table:
Field | Type | Description |
---|---|---|
|
|
The name of the CNO object. This name is always |
|
| A list specifying the blocks of IP addresses from which pod IP addresses are allocated and the subnet prefix length assigned to each individual node in the cluster. For example: spec: clusterNetwork: - cidr: 10.128.0.0/19 hostPrefix: 23 - cidr: 10.128.32.0/19 hostPrefix: 23
You can customize this field only in the |
|
| A block of IP addresses for services. The OpenShift SDN and OVN-Kubernetes network plugins support only a single IP address block for the service network. For example: spec: serviceNetwork: - 172.30.0.0/14
You can customize this field only in the |
|
| Configures the network plugin for the cluster network. |
|
| The fields for this object specify the kube-proxy configuration. If you are using the OVN-Kubernetes cluster network plugin, the kube-proxy configuration has no effect. |
defaultNetwork object configuration
The values for the defaultNetwork
object are defined in the following table:
Field | Type | Description |
---|---|---|
|
|
Either Note OpenShift Container Platform uses the OVN-Kubernetes network plugin by default. |
|
| This object is only valid for the OpenShift SDN network plugin. |
|
| This object is only valid for the OVN-Kubernetes network plugin. |
Configuration for the OpenShift SDN network plugin
The following table describes the configuration fields for the OpenShift SDN network plugin:
Field | Type | Description |
---|---|---|
|
|
Configures the network isolation mode for OpenShift SDN. The default value is
The values |
|
| The maximum transmission unit (MTU) for the VXLAN overlay network. This is detected automatically based on the MTU of the primary network interface. You do not normally need to override the detected MTU. If the auto-detected value is not what you expect it to be, confirm that the MTU on the primary network interface on your nodes is correct. You cannot use this option to change the MTU value of the primary network interface on the nodes.
If your cluster requires different MTU values for different nodes, you must set this value to This value cannot be changed after cluster installation. |
|
|
The port to use for all VXLAN packets. The default value is If you are running in a virtualized environment with existing nodes that are part of another VXLAN network, then you might be required to change this. For example, when running an OpenShift SDN overlay on top of VMware NSX-T, you must select an alternate port for the VXLAN, because both SDNs use the same default VXLAN port number.
On Amazon Web Services (AWS), you can select an alternate port for the VXLAN between port |
Example OpenShift SDN configuration
defaultNetwork: type: OpenShiftSDN openshiftSDNConfig: mode: NetworkPolicy mtu: 1450 vxlanPort: 4789
Configuration for the OVN-Kubernetes network plugin
The following table describes the configuration fields for the OVN-Kubernetes network plugin:
Field | Type | Description |
---|---|---|
|
| The maximum transmission unit (MTU) for the Geneve (Generic Network Virtualization Encapsulation) overlay network. This is detected automatically based on the MTU of the primary network interface. You do not normally need to override the detected MTU. If the auto-detected value is not what you expect it to be, confirm that the MTU on the primary network interface on your nodes is correct. You cannot use this option to change the MTU value of the primary network interface on the nodes.
If your cluster requires different MTU values for different nodes, you must set this value to |
|
|
The port to use for all Geneve packets. The default value is |
|
| Specify an empty object to enable IPsec encryption. |
|
| Specify a configuration object for customizing network policy audit logging. If unset, the defaults audit log settings are used. |
|
| Optional: Specify a configuration object for customizing how egress traffic is sent to the node gateway. Note While migrating egress traffic, you can expect some disruption to workloads and service traffic until the Cluster Network Operator (CNO) successfully rolls out the changes. |
|
If your existing network infrastructure overlaps with the This field cannot be changed after installation. |
The default value is |
|
If your existing network infrastructure overlaps with the This field cannot be changed after installation. |
The default value is |
Field | Type | Description |
---|---|---|
| integer |
The maximum number of messages to generate every second per node. The default value is |
| integer |
The maximum size for the audit log in bytes. The default value is |
| integer | The maximum number of log files that are retained. |
| string | One of the following additional audit log targets:
|
| string |
The syslog facility, such as |
Field | Type | Description |
---|---|---|
|
|
Set this field to
This field has an interaction with the Open vSwitch hardware offloading feature. If you set this field to |
Example OVN-Kubernetes configuration with IPSec enabled
defaultNetwork: type: OVNKubernetes ovnKubernetesConfig: mtu: 1400 genevePort: 6081 ipsecConfig: {}
kubeProxyConfig object configuration
The values for the kubeProxyConfig
object are defined in the following table:
Field | Type | Description |
---|---|---|
|
|
The refresh period for Note
Because of performance improvements introduced in OpenShift Container Platform 4.3 and greater, adjusting the |
|
|
The minimum duration before refreshing kubeProxyConfig: proxyArguments: iptables-min-sync-period: - 0s |
3.13. Creating the Ignition config files
Because you must manually start the cluster machines, you must generate the Ignition config files that the cluster needs to make its machines.
-
The Ignition config files that the installation program generates contain certificates that expire after 24 hours, which are then renewed at that time. If the cluster is shut down before renewing the certificates and the cluster is later restarted after the 24 hours have elapsed, the cluster automatically recovers the expired certificates. The exception is that you must manually approve the pending
node-bootstrapper
certificate signing requests (CSRs) to recover kubelet certificates. See the documentation for Recovering from expired control plane certificates for more information. - It is recommended that you use Ignition config files within 12 hours after they are generated because the 24-hour certificate rotates from 16 to 22 hours after the cluster is installed. By using the Ignition config files within 12 hours, you can avoid installation failure if the certificate update runs during installation.
Prerequisites
- Obtain the OpenShift Container Platform installation program and the pull secret for your cluster.
Procedure
Obtain the Ignition config files:
$ ./openshift-install create ignition-configs --dir <installation_directory> 1
- 1
- For
<installation_directory>
, specify the directory name to store the files that the installation program creates.
ImportantIf you created an
install-config.yaml
file, specify the directory that contains it. Otherwise, specify an empty directory. Some installation assets, like bootstrap X.509 certificates have short expiration intervals, so you must not reuse an installation directory. If you want to reuse individual files from another cluster installation, you can copy them into your directory. However, the file names for the installation assets might change between releases. Use caution when copying installation files from an earlier OpenShift Container Platform version.The following files are generated in the directory:
. ├── auth │ ├── kubeadmin-password │ └── kubeconfig ├── bootstrap.ign ├── master.ign ├── metadata.json └── worker.ign
3.14. Installing RHCOS and starting the OpenShift Container Platform bootstrap process
To install OpenShift Container Platform on bare metal infrastructure that you provision, you must install Red Hat Enterprise Linux CoreOS (RHCOS) on the machines. When you install RHCOS, you must provide the Ignition config file that was generated by the OpenShift Container Platform installation program for the type of machine you are installing. If you have configured suitable networking, DNS, and load balancing infrastructure, the OpenShift Container Platform bootstrap process begins automatically after the RHCOS machines have rebooted.
To install RHCOS on the machines, follow either the steps to use an ISO image or network PXE booting.
The compute node deployment steps included in this installation document are RHCOS-specific. If you choose instead to deploy RHEL-based compute nodes, you take responsibility for all operating system life cycle management and maintenance, including performing system updates, applying patches, and completing all other required tasks. Only RHEL 8 compute machines are supported.
You can configure RHCOS during ISO and PXE installations by using the following methods:
-
Kernel arguments: You can use kernel arguments to provide installation-specific information. For example, you can specify the locations of the RHCOS installation files that you uploaded to your HTTP server and the location of the Ignition config file for the type of node you are installing. For a PXE installation, you can use the
APPEND
parameter to pass the arguments to the kernel of the live installer. For an ISO installation, you can interrupt the live installation boot process to add the kernel arguments. In both installation cases, you can use specialcoreos.inst.*
arguments to direct the live installer, as well as standard installation boot arguments for turning standard kernel services on or off. -
Ignition configs: OpenShift Container Platform Ignition config files (
*.ign
) are specific to the type of node you are installing. You pass the location of a bootstrap, control plane, or compute node Ignition config file during the RHCOS installation so that it takes effect on first boot. In special cases, you can create a separate, limited Ignition config to pass to the live system. That Ignition config could do a certain set of tasks, such as reporting success to a provisioning system after completing installation. This special Ignition config is consumed by thecoreos-installer
to be applied on first boot of the installed system. Do not provide the standard control plane and compute node Ignition configs to the live ISO directly. -
coreos-installer
: You can boot the live ISO installer to a shell prompt, which allows you to prepare the permanent system in a variety of ways before first boot. In particular, you can run thecoreos-installer
command to identify various artifacts to include, work with disk partitions, and set up networking. In some cases, you can configure features on the live system and copy them to the installed system.
Whether to use an ISO or PXE install depends on your situation. A PXE install requires an available DHCP service and more preparation, but can make the installation process more automated. An ISO install is a more manual process and can be inconvenient if you are setting up more than a few machines.
As of OpenShift Container Platform 4.6, the RHCOS ISO and other installation artifacts provide support for installation on disks with 4K sectors.
3.14.1. Installing RHCOS by using an ISO image
You can use an ISO image to install RHCOS on the machines.
Prerequisites
- You have created the Ignition config files for your cluster.
- You have configured suitable network, DNS and load balancing infrastructure.
- You have an HTTP server that can be accessed from your computer, and from the machines that you create.
- You have reviewed the Advanced RHCOS installation configuration section for different ways to configure features, such as networking and disk partitioning.
Procedure
Obtain the SHA512 digest for each of your Ignition config files. For example, you can use the following on a system running Linux to get the SHA512 digest for your
bootstrap.ign
Ignition config file:$ sha512sum <installation_directory>/bootstrap.ign
The digests are provided to the
coreos-installer
in a later step to validate the authenticity of the Ignition config files on the cluster nodes.Upload the bootstrap, control plane, and compute node Ignition config files that the installation program created to your HTTP server. Note the URLs of these files.
ImportantYou can add or change configuration settings in your Ignition configs before saving them to your HTTP server. If you plan to add more compute machines to your cluster after you finish installation, do not delete these files.
From the installation host, validate that the Ignition config files are available on the URLs. The following example gets the Ignition config file for the bootstrap node:
$ curl -k http://<HTTP_server>/bootstrap.ign 1
Example output
% Total % Received % Xferd Average Speed Time Time Time Current Dload Upload Total Spent Left Speed 0 0 0 0 0 0 0 0 --:--:-- --:--:-- --:--:-- 0{"ignition":{"version":"3.2.0"},"passwd":{"users":[{"name":"core","sshAuthorizedKeys":["ssh-rsa...
Replace
bootstrap.ign
withmaster.ign
orworker.ign
in the command to validate that the Ignition config files for the control plane and compute nodes are also available.Although it is possible to obtain the RHCOS images that are required for your preferred method of installing operating system instances from the RHCOS image mirror page, the recommended way to obtain the correct version of your RHCOS images are from the output of
openshift-install
command:$ openshift-install coreos print-stream-json | grep '\.iso[^.]'
Example output
"location": "<url>/art/storage/releases/rhcos-4.13-aarch64/<release>/aarch64/rhcos-<release>-live.aarch64.iso", "location": "<url>/art/storage/releases/rhcos-4.13-ppc64le/<release>/ppc64le/rhcos-<release>-live.ppc64le.iso", "location": "<url>/art/storage/releases/rhcos-4.13-s390x/<release>/s390x/rhcos-<release>-live.s390x.iso", "location": "<url>/art/storage/releases/rhcos-4.13/<release>/x86_64/rhcos-<release>-live.x86_64.iso",
ImportantThe RHCOS images might not change with every release of OpenShift Container Platform. You must download images with the highest version that is less than or equal to the OpenShift Container Platform version that you install. Use the image versions that match your OpenShift Container Platform version if they are available. Use only ISO images for this procedure. RHCOS qcow2 images are not supported for this installation type.
ISO file names resemble the following example:
rhcos-<version>-live.<architecture>.iso
Use the ISO to start the RHCOS installation. Use one of the following installation options:
- Burn the ISO image to a disk and boot it directly.
- Use ISO redirection by using a lights-out management (LOM) interface.
Boot the RHCOS ISO image without specifying any options or interrupting the live boot sequence. Wait for the installer to boot into a shell prompt in the RHCOS live environment.
NoteIt is possible to interrupt the RHCOS installation boot process to add kernel arguments. However, for this ISO procedure you should use the
coreos-installer
command as outlined in the following steps, instead of adding kernel arguments.Run the
coreos-installer
command and specify the options that meet your installation requirements. At a minimum, you must specify the URL that points to the Ignition config file for the node type, and the device that you are installing to:$ sudo coreos-installer install --ignition-url=http://<HTTP_server>/<node_type>.ign <device> --ignition-hash=sha512-<digest> 12
- 1 1
- You must run the
coreos-installer
command by usingsudo
, because thecore
user does not have the required root privileges to perform the installation. - 2
- The
--ignition-hash
option is required when the Ignition config file is obtained through an HTTP URL to validate the authenticity of the Ignition config file on the cluster node.<digest>
is the Ignition config file SHA512 digest obtained in a preceding step.
NoteIf you want to provide your Ignition config files through an HTTPS server that uses TLS, you can add the internal certificate authority (CA) to the system trust store before running
coreos-installer
.The following example initializes a bootstrap node installation to the
/dev/sda
device. The Ignition config file for the bootstrap node is obtained from an HTTP web server with the IP address 192.168.1.2:$ sudo coreos-installer install --ignition-url=http://192.168.1.2:80/installation_directory/bootstrap.ign /dev/sda --ignition-hash=sha512-a5a2d43879223273c9b60af66b44202a1d1248fc01cf156c46d4a79f552b6bad47bc8cc78ddf0116e80c59d2ea9e32ba53bc807afbca581aa059311def2c3e3b
Monitor the progress of the RHCOS installation on the console of the machine.
ImportantBe sure that the installation is successful on each node before commencing with the OpenShift Container Platform installation. Observing the installation process can also help to determine the cause of RHCOS installation issues that might arise.
- After RHCOS installs, you must reboot the system. During the system reboot, it applies the Ignition config file that you specified.
Check the console output to verify that Ignition ran.
Example command
Ignition: ran on 2022/03/14 14:48:33 UTC (this boot) Ignition: user-provided config was applied
Continue to create the other machines for your cluster.
ImportantYou must create the bootstrap and control plane machines at this time. If the control plane machines are not made schedulable, also create at least two compute machines before you install OpenShift Container Platform.
If the required network, DNS, and load balancer infrastructure are in place, the OpenShift Container Platform bootstrap process begins automatically after the RHCOS nodes have rebooted.
NoteRHCOS nodes do not include a default password for the
core
user. You can access the nodes by runningssh core@<node>.<cluster_name>.<base_domain>
as a user with access to the SSH private key that is paired to the public key that you specified in yourinstall_config.yaml
file. OpenShift Container Platform 4 cluster nodes running RHCOS are immutable and rely on Operators to apply cluster changes. Accessing cluster nodes by using SSH is not recommended. However, when investigating installation issues, if the OpenShift Container Platform API is not available, or the kubelet is not properly functioning on a target node, SSH access might be required for debugging or disaster recovery.
3.14.2. Installing RHCOS by using PXE or iPXE booting
You can use PXE or iPXE booting to install RHCOS on the machines.
Prerequisites
- You have created the Ignition config files for your cluster.
- You have configured suitable network, DNS and load balancing infrastructure.
- You have configured suitable PXE or iPXE infrastructure.
- You have an HTTP server that can be accessed from your computer, and from the machines that you create.
- You have reviewed the Advanced RHCOS installation configuration section for different ways to configure features, such as networking and disk partitioning.
Procedure
Upload the bootstrap, control plane, and compute node Ignition config files that the installation program created to your HTTP server. Note the URLs of these files.
ImportantYou can add or change configuration settings in your Ignition configs before saving them to your HTTP server. If you plan to add more compute machines to your cluster after you finish installation, do not delete these files.
From the installation host, validate that the Ignition config files are available on the URLs. The following example gets the Ignition config file for the bootstrap node:
$ curl -k http://<HTTP_server>/bootstrap.ign 1
Example output
% Total % Received % Xferd Average Speed Time Time Time Current Dload Upload Total Spent Left Speed 0 0 0 0 0 0 0 0 --:--:-- --:--:-- --:--:-- 0{"ignition":{"version":"3.2.0"},"passwd":{"users":[{"name":"core","sshAuthorizedKeys":["ssh-rsa...
Replace
bootstrap.ign
withmaster.ign
orworker.ign
in the command to validate that the Ignition config files for the control plane and compute nodes are also available.Although it is possible to obtain the RHCOS
kernel
,initramfs
androotfs
files that are required for your preferred method of installing operating system instances from the RHCOS image mirror page, the recommended way to obtain the correct version of your RHCOS files are from the output ofopenshift-install
command:$ openshift-install coreos print-stream-json | grep -Eo '"https.*(kernel-|initramfs.|rootfs.)\w+(\.img)?"'
Example output
"<url>/art/storage/releases/rhcos-4.13-aarch64/<release>/aarch64/rhcos-<release>-live-kernel-aarch64" "<url>/art/storage/releases/rhcos-4.13-aarch64/<release>/aarch64/rhcos-<release>-live-initramfs.aarch64.img" "<url>/art/storage/releases/rhcos-4.13-aarch64/<release>/aarch64/rhcos-<release>-live-rootfs.aarch64.img" "<url>/art/storage/releases/rhcos-4.13-ppc64le/49.84.202110081256-0/ppc64le/rhcos-<release>-live-kernel-ppc64le" "<url>/art/storage/releases/rhcos-4.13-ppc64le/<release>/ppc64le/rhcos-<release>-live-initramfs.ppc64le.img" "<url>/art/storage/releases/rhcos-4.13-ppc64le/<release>/ppc64le/rhcos-<release>-live-rootfs.ppc64le.img" "<url>/art/storage/releases/rhcos-4.13-s390x/<release>/s390x/rhcos-<release>-live-kernel-s390x" "<url>/art/storage/releases/rhcos-4.13-s390x/<release>/s390x/rhcos-<release>-live-initramfs.s390x.img" "<url>/art/storage/releases/rhcos-4.13-s390x/<release>/s390x/rhcos-<release>-live-rootfs.s390x.img" "<url>/art/storage/releases/rhcos-4.13/<release>/x86_64/rhcos-<release>-live-kernel-x86_64" "<url>/art/storage/releases/rhcos-4.13/<release>/x86_64/rhcos-<release>-live-initramfs.x86_64.img" "<url>/art/storage/releases/rhcos-4.13/<release>/x86_64/rhcos-<release>-live-rootfs.x86_64.img"
ImportantThe RHCOS artifacts might not change with every release of OpenShift Container Platform. You must download images with the highest version that is less than or equal to the OpenShift Container Platform version that you install. Only use the appropriate
kernel
,initramfs
, androotfs
artifacts described below for this procedure. RHCOS QCOW2 images are not supported for this installation type.The file names contain the OpenShift Container Platform version number. They resemble the following examples:
-
kernel
:rhcos-<version>-live-kernel-<architecture>
-
initramfs
:rhcos-<version>-live-initramfs.<architecture>.img
-
rootfs
:rhcos-<version>-live-rootfs.<architecture>.img
-
Upload the
rootfs
,kernel
, andinitramfs
files to your HTTP server.ImportantIf you plan to add more compute machines to your cluster after you finish installation, do not delete these files.
- Configure the network boot infrastructure so that the machines boot from their local disks after RHCOS is installed on them.
Configure PXE or iPXE installation for the RHCOS images and begin the installation.
Modify one of the following example menu entries for your environment and verify that the image and Ignition files are properly accessible:
For PXE (
x86_64
):DEFAULT pxeboot TIMEOUT 20 PROMPT 0 LABEL pxeboot KERNEL http://<HTTP_server>/rhcos-<version>-live-kernel-<architecture> 1 APPEND initrd=http://<HTTP_server>/rhcos-<version>-live-initramfs.<architecture>.img coreos.live.rootfs_url=http://<HTTP_server>/rhcos-<version>-live-rootfs.<architecture>.img coreos.inst.install_dev=/dev/sda coreos.inst.ignition_url=http://<HTTP_server>/bootstrap.ign 2 3
- 1 1
- Specify the location of the live
kernel
file that you uploaded to your HTTP server. The URL must be HTTP, TFTP, or FTP; HTTPS and NFS are not supported. - 2
- If you use multiple NICs, specify a single interface in the
ip
option. For example, to use DHCP on a NIC that is namedeno1
, setip=eno1:dhcp
. - 3
- Specify the locations of the RHCOS files that you uploaded to your HTTP server. The
initrd
parameter value is the location of theinitramfs
file, thecoreos.live.rootfs_url
parameter value is the location of therootfs
file, and thecoreos.inst.ignition_url
parameter value is the location of the bootstrap Ignition config file. You can also add more kernel arguments to theAPPEND
line to configure networking or other boot options.
NoteThis configuration does not enable serial console access on machines with a graphical console. To configure a different console, add one or more
console=
arguments to theAPPEND
line. For example, addconsole=tty0 console=ttyS0
to set the first PC serial port as the primary console and the graphical console as a secondary console. For more information, see How does one set up a serial terminal and/or console in Red Hat Enterprise Linux? and "Enabling the serial console for PXE and ISO installation" in the "Advanced RHCOS installation configuration" section.For iPXE (
x86_64
+aarch64
):kernel http://<HTTP_server>/rhcos-<version>-live-kernel-<architecture> initrd=main coreos.live.rootfs_url=http://<HTTP_server>/rhcos-<version>-live-rootfs.<architecture>.img coreos.inst.install_dev=/dev/sda coreos.inst.ignition_url=http://<HTTP_server>/bootstrap.ign 1 2 initrd --name main http://<HTTP_server>/rhcos-<version>-live-initramfs.<architecture>.img 3 boot
- 1
- Specify the locations of the RHCOS files that you uploaded to your HTTP server. The
kernel
parameter value is the location of thekernel
file, theinitrd=main
argument is needed for booting on UEFI systems, thecoreos.live.rootfs_url
parameter value is the location of therootfs
file, and thecoreos.inst.ignition_url
parameter value is the location of the bootstrap Ignition config file. - 2
- If you use multiple NICs, specify a single interface in the
ip
option. For example, to use DHCP on a NIC that is namedeno1
, setip=eno1:dhcp
. - 3
- Specify the location of the
initramfs
file that you uploaded to your HTTP server.
NoteThis configuration does not enable serial console access on machines with a graphical console. To configure a different console, add one or more
console=
arguments to thekernel
line. For example, addconsole=tty0 console=ttyS0
to set the first PC serial port as the primary console and the graphical console as a secondary console. For more information, see How does one set up a serial terminal and/or console in Red Hat Enterprise Linux? and "Enabling the serial console for PXE and ISO installation" in the "Advanced RHCOS installation configuration" section.NoteTo network boot the CoreOS
kernel
onaarch64
architecture, you need to use a version of iPXE build with theIMAGE_GZIP
option enabled. SeeIMAGE_GZIP
option in iPXE.For PXE (with UEFI and Grub as second stage) on
aarch64
:menuentry 'Install CoreOS' { linux rhcos-<version>-live-kernel-<architecture> coreos.live.rootfs_url=http://<HTTP_server>/rhcos-<version>-live-rootfs.<architecture>.img coreos.inst.install_dev=/dev/sda coreos.inst.ignition_url=http://<HTTP_server>/bootstrap.ign 1 2 initrd rhcos-<version>-live-initramfs.<architecture>.img 3 }
- 1
- Specify the locations of the RHCOS files that you uploaded to your HTTP/TFTP server. The
kernel
parameter value is the location of thekernel
file on your TFTP server. Thecoreos.live.rootfs_url
parameter value is the location of therootfs
file, and thecoreos.inst.ignition_url
parameter value is the location of the bootstrap Ignition config file on your HTTP Server. - 2
- If you use multiple NICs, specify a single interface in the
ip
option. For example, to use DHCP on a NIC that is namedeno1
, setip=eno1:dhcp
. - 3
- Specify the location of the
initramfs
file that you uploaded to your TFTP server.
Monitor the progress of the RHCOS installation on the console of the machine.
ImportantBe sure that the installation is successful on each node before commencing with the OpenShift Container Platform installation. Observing the installation process can also help to determine the cause of RHCOS installation issues that might arise.
- After RHCOS installs, the system reboots. During reboot, the system applies the Ignition config file that you specified.
Check the console output to verify that Ignition ran.
Example command
Ignition: ran on 2022/03/14 14:48:33 UTC (this boot) Ignition: user-provided config was applied
Continue to create the machines for your cluster.
ImportantYou must create the bootstrap and control plane machines at this time. If the control plane machines are not made schedulable, also create at least two compute machines before you install the cluster.
If the required network, DNS, and load balancer infrastructure are in place, the OpenShift Container Platform bootstrap process begins automatically after the RHCOS nodes have rebooted.
NoteRHCOS nodes do not include a default password for the
core
user. You can access the nodes by runningssh core@<node>.<cluster_name>.<base_domain>
as a user with access to the SSH private key that is paired to the public key that you specified in yourinstall_config.yaml
file. OpenShift Container Platform 4 cluster nodes running RHCOS are immutable and rely on Operators to apply cluster changes. Accessing cluster nodes by using SSH is not recommended. However, when investigating installation issues, if the OpenShift Container Platform API is not available, or the kubelet is not properly functioning on a target node, SSH access might be required for debugging or disaster recovery.
3.14.3. Advanced RHCOS installation configuration
A key benefit for manually provisioning the Red Hat Enterprise Linux CoreOS (RHCOS) nodes for OpenShift Container Platform is to be able to do configuration that is not available through default OpenShift Container Platform installation methods. This section describes some of the configurations that you can do using techniques that include:
- Passing kernel arguments to the live installer
-
Running
coreos-installer
manually from the live system - Customizing a live ISO or PXE boot image
The advanced configuration topics for manual Red Hat Enterprise Linux CoreOS (RHCOS) installations detailed in this section relate to disk partitioning, networking, and using Ignition configs in different ways.
3.14.3.1. Using advanced networking options for PXE and ISO installations
Networking for OpenShift Container Platform nodes uses DHCP by default to gather all necessary configuration settings. To set up static IP addresses or configure special settings, such as bonding, you can do one of the following:
- Pass special kernel parameters when you boot the live installer.
- Use a machine config to copy networking files to the installed system.
- Configure networking from a live installer shell prompt, then copy those settings to the installed system so that they take effect when the installed system first boots.
To configure a PXE or iPXE installation, use one of the following options:
- See the "Advanced RHCOS installation reference" tables.
- Use a machine config to copy networking files to the installed system.
To configure an ISO installation, use the following procedure.
Procedure
- Boot the ISO installer.
-
From the live system shell prompt, configure networking for the live system using available RHEL tools, such as
nmcli
ornmtui
. Run the
coreos-installer
command to install the system, adding the--copy-network
option to copy networking configuration. For example:$ sudo coreos-installer install --copy-network \ --ignition-url=http://host/worker.ign /dev/disk/by-id/scsi-<serial_number>
ImportantThe
--copy-network
option only copies networking configuration found under/etc/NetworkManager/system-connections
. In particular, it does not copy the system hostname.- Reboot into the installed system.
Additional resources
-
See Getting started with nmcli and Getting started with nmtui in the RHEL 8 documentation for more information about the
nmcli
andnmtui
tools.
3.14.3.2. Disk partitioning
Disk partitions are created on OpenShift Container Platform cluster nodes during the Red Hat Enterprise Linux CoreOS (RHCOS) installation. Each RHCOS node of a particular architecture uses the same partition layout, unless you override the default partitioning configuration. During the RHCOS installation, the size of the root file system is increased to use any remaining available space on the target device.
The use of a custom partition scheme on your node might result in OpenShift Container Platform not monitoring or alerting on some node partitions. If you override the default partitioning, see Understanding OpenShift File System Monitoring (eviction conditions) for more information about how OpenShift Container Platform monitors your host file systems.
OpenShift Container Platform monitors the following two filesystem identifiers:
-
nodefs
, which is the filesystem that contains/var/lib/kubelet
-
imagefs
, which is the filesystem that contains/var/lib/containers
For the default partition scheme, nodefs
and imagefs
monitor the same root filesystem, /
.
To override the default partitioning when installing RHCOS on an OpenShift Container Platform cluster node, you must create separate partitions.
For disk sizes larger than 100GB, and especially disk sizes larger than 1TB, create a separate /var
partition. See "Creating a separate /var
partition" and this Red Hat Knowledgebase article for more information.
Consider a situation where you want to add a separate storage partition for your containers and container images. For example, by mounting /var/lib/containers
in a separate partition, the kubelet separately monitors /var/lib/containers
as the imagefs
directory and the root file system as the nodefs
directory.
If you have resized your disk size to host a larger file system, consider creating a separate /var/lib/containers
partition. Consider resizing a disk that has an xfs
format to reduce CPU time issues caused by a high number of allocation groups.
3.14.3.2.1. Creating a separate /var
partition
In general, you should use the default disk partitioning that is created during the RHCOS installation. However, there are cases where you might want to create a separate partition for a directory that you expect to grow.
OpenShift Container Platform supports the addition of a single partition to attach storage to either the /var
directory or a subdirectory of /var
. For example:
-
/var/lib/containers
: Holds container-related content that can grow as more images and containers are added to a system. -
/var/lib/etcd
: Holds data that you might want to keep separate for purposes such as performance optimization of etcd storage. /var
: Holds data that you might want to keep separate for purposes such as auditing.ImportantFor disk sizes larger than 100GB, and especially larger than 1TB, create a separate
/var
partition.
Storing the contents of a /var
directory separately makes it easier to grow storage for those areas as needed and reinstall OpenShift Container Platform at a later date and keep that data intact. With this method, you will not have to pull all your containers again, nor will you have to copy massive log files when you update systems.
The use of a separate partition for the /var
directory or a subdirectory of /var
also prevents data growth in the partitioned directory from filling up the root file system.
The following procedure sets up a separate /var
partition by adding a machine config manifest that is wrapped into the Ignition config file for a node type during the preparation phase of an installation.
Procedure
On your installation host, change to the directory that contains the OpenShift Container Platform installation program and generate the Kubernetes manifests for the cluster:
$ openshift-install create manifests --dir <installation_directory>
Create a Butane config that configures the additional partition. For example, name the file
$HOME/clusterconfig/98-var-partition.bu
, change the disk device name to the name of the storage device on theworker
systems, and set the storage size as appropriate. This example places the/var
directory on a separate partition:variant: openshift version: 4.13.0 metadata: labels: machineconfiguration.openshift.io/role: worker name: 98-var-partition storage: disks: - device: /dev/disk/by-id/<device_name> 1 partitions: - label: var start_mib: <partition_start_offset> 2 size_mib: <partition_size> 3 number: 5 filesystems: - device: /dev/disk/by-partlabel/var path: /var format: xfs mount_options: [defaults, prjquota] 4 with_mount_unit: true
- 1
- The storage device name of the disk that you want to partition.
- 2
- When adding a data partition to the boot disk, a minimum offset value of 25000 mebibytes is recommended. The root file system is automatically resized to fill all available space up to the specified offset. If no offset value is specified, or if the specified value is smaller than the recommended minimum, the resulting root file system will be too small, and future reinstalls of RHCOS might overwrite the beginning of the data partition.
- 3
- The size of the data partition in mebibytes.
- 4
- The
prjquota
mount option must be enabled for filesystems used for container storage.
NoteWhen creating a separate
/var
partition, you cannot use different instance types for compute nodes, if the different instance types do not have the same device name.Create a manifest from the Butane config and save it to the
clusterconfig/openshift
directory. For example, run the following command:$ butane $HOME/clusterconfig/98-var-partition.bu -o $HOME/clusterconfig/openshift/98-var-partition.yaml
Create the Ignition config files:
$ openshift-install create ignition-configs --dir <installation_directory> 1
- 1
- For
<installation_directory>
, specify the same installation directory.
Ignition config files are created for the bootstrap, control plane, and compute nodes in the installation directory:
. ├── auth │ ├── kubeadmin-password │ └── kubeconfig ├── bootstrap.ign ├── master.ign ├── metadata.json └── worker.ign
The files in the
<installation_directory>/manifest
and<installation_directory>/openshift
directories are wrapped into the Ignition config files, including the file that contains the98-var-partition
customMachineConfig
object.
Next steps
- You can apply the custom disk partitioning by referencing the Ignition config files during the RHCOS installations.
3.14.3.2.2. Retaining existing partitions
For an ISO installation, you can add options to the coreos-installer
command that cause the installer to maintain one or more existing partitions. For a PXE installation, you can add coreos.inst.*
options to the APPEND
parameter to preserve partitions.
Saved partitions might be data partitions from an existing OpenShift Container Platform system. You can identify the disk partitions you want to keep either by partition label or by number.
If you save existing partitions, and those partitions do not leave enough space for RHCOS, the installation will fail without damaging the saved partitions.
Retaining existing partitions during an ISO installation
This example preserves any partition in which the partition label begins with data
(data*
):
# coreos-installer install --ignition-url http://10.0.2.2:8080/user.ign \ --save-partlabel 'data*' /dev/disk/by-id/scsi-<serial_number>
The following example illustrates running the coreos-installer
in a way that preserves the sixth (6) partition on the disk:
# coreos-installer install --ignition-url http://10.0.2.2:8080/user.ign \ --save-partindex 6 /dev/disk/by-id/scsi-<serial_number>
This example preserves partitions 5 and higher:
# coreos-installer install --ignition-url http://10.0.2.2:8080/user.ign --save-partindex 5- /dev/disk/by-id/scsi-<serial_number>
In the previous examples where partition saving is used, coreos-installer
recreates the partition immediately.
Retaining existing partitions during a PXE installation
This APPEND
option preserves any partition in which the partition label begins with 'data' ('data*'):
coreos.inst.save_partlabel=data*
This APPEND
option preserves partitions 5 and higher:
coreos.inst.save_partindex=5-
This APPEND
option preserves partition 6:
coreos.inst.save_partindex=6
3.14.3.3. Identifying Ignition configs
When doing an RHCOS manual installation, there are two types of Ignition configs that you can provide, with different reasons for providing each one:
Permanent install Ignition config: Every manual RHCOS installation needs to pass one of the Ignition config files generated by
openshift-installer
, such asbootstrap.ign
,master.ign
andworker.ign
, to carry out the installation.ImportantIt is not recommended to modify these Ignition config files directly. You can update the manifest files that are wrapped into the Ignition config files, as outlined in examples in the preceding sections.
For PXE installations, you pass the Ignition configs on the
APPEND
line using thecoreos.inst.ignition_url=
option. For ISO installations, after the ISO boots to the shell prompt, you identify the Ignition config on thecoreos-installer
command line with the--ignition-url=
option. In both cases, only HTTP and HTTPS protocols are supported.Live install Ignition config: This type can be created by using the
coreos-installer
customize
subcommand and its various options. With this method, the Ignition config passes to the live install medium, runs immediately upon booting, and performs setup tasks before or after the RHCOS system installs to disk. This method should only be used for performing tasks that must be done once and not applied again later, such as with advanced partitioning that cannot be done using a machine config.For PXE or ISO boots, you can create the Ignition config and
APPEND
theignition.config.url=
option to identify the location of the Ignition config. You also need to appendignition.firstboot ignition.platform.id=metal
or theignition.config.url
option will be ignored.
3.14.3.4. Default console configuration
Red Hat Enterprise Linux CoreOS (RHCOS) nodes installed from an OpenShift Container Platform 4.13 boot image use a default console that is meant to accomodate most virtualized and bare metal setups. Different cloud and virtualization platforms may use different default settings depending on the chosen architecture. Bare metal installations use the kernel default settings which typically means the graphical console is the primary console and the serial console is disabled.
The default consoles may not match your specific hardware configuration or you might have specific needs that require you to adjust the default console. For example:
- You want to access the emergency shell on the console for debugging purposes.
- Your cloud platform does not provide interactive access to the graphical console, but provides a serial console.
- You want to enable multiple consoles.
Console configuration is inherited from the boot image. This means that new nodes in existing clusters are unaffected by changes to the default console.
You can configure the console for bare metal installations in the following ways:
-
Using
coreos-installer
manually on the command line. -
Using the
coreos-installer iso customize
orcoreos-installer pxe customize
subcommands with the--dest-console
option to create a custom image that automates the process.
For advanced customization, perform console configuration using the coreos-installer iso
or coreos-installer pxe
subcommands, and not kernel arguments.
3.14.3.5. Enabling the serial console for PXE and ISO installations
By default, the Red Hat Enterprise Linux CoreOS (RHCOS) serial console is disabled and all output is written to the graphical console. You can enable the serial console for an ISO installation and reconfigure the bootloader so that output is sent to both the serial console and the graphical console.
Procedure
- Boot the ISO installer.
Run the
coreos-installer
command to install the system, adding the--console
option once to specify the graphical console, and a second time to specify the serial console:$ coreos-installer install \ --console=tty0 \1 --console=ttyS0,<options> \2 --ignition-url=http://host/worker.ign /dev/disk/by-id/scsi-<serial_number>
- 1
- The desired secondary console. In this case, the graphical console. Omitting this option will disable the graphical console.
- 2
- The desired primary console. In this case the serial console. The
options
field defines the baud rate and other settings. A common value for this field is11520n8
. If no options are provided, the default kernel value of9600n8
is used. For more information on the format of this option, see Linux kernel serial console documentation.
Reboot into the installed system.
NoteA similar outcome can be obtained by using the
coreos-installer install --append-karg
option, and specifying the console withconsole=
. However, this will only set the console for the kernel and not the bootloader.
To configure a PXE installation, make sure the coreos.inst.install_dev
kernel command line option is omitted, and use the shell prompt to run coreos-installer
manually using the above ISO installation procedure.
3.14.3.6. Customizing a live RHCOS ISO or PXE install
You can use the live ISO image or PXE environment to install RHCOS by injecting an Ignition config file directly into the image. This creates a customized image that you can use to provision your system.
For an ISO image, the mechanism to do this is the coreos-installer iso customize
subcommand, which modifies the .iso
file with your configuration. Similarly, the mechanism for a PXE environment is the coreos-installer pxe customize
subcommand, which creates a new initramfs
file that includes your customizations.
The customize
subcommand is a general purpose tool that can embed other types of customizations as well. The following tasks are examples of some of the more common customizations:
- Inject custom CA certificates for when corporate security policy requires their use.
- Configure network settings without the need for kernel arguments.
- Embed arbitrary preinstall and post-install scripts or binaries.
3.14.3.7. Customizing a live RHCOS ISO image
You can customize a live RHCOS ISO image directly with the coreos-installer iso customize
subcommand. When you boot the ISO image, the customizations are applied automatically.
You can use this feature to configure the ISO image to automatically install RHCOS.
Procedure
-
Download the
coreos-installer
binary from thecoreos-installer
image mirror page. Retrieve the RHCOS ISO image from the RHCOS image mirror page and the Ignition config file, and then run the following command to inject the Ignition config directly into the ISO image:
$ coreos-installer iso customize rhcos-<version>-live.x86_64.iso \ --dest-ignition bootstrap.ign \ 1 --dest-device /dev/disk/by-id/scsi-<serial_number> 2
- 1
- The Ignition config file that is generated from the
openshift-installer
installation program. - 2
- When you specify this option, the ISO image automatically runs an installation. Otherwise, the image remains configured for installation, but does not install automatically unless you specify the
coreos.inst.install_dev
kernel argument.
Optional: To remove the ISO image customizations and return the image to its pristine state, run:
$ coreos-installer iso reset rhcos-<version>-live.x86_64.iso
You can now re-customize the live ISO image or use it in its pristine state.
Applying your customizations affects every subsequent boot of RHCOS.
3.14.3.7.1. Modifying a live install ISO image to enable the serial console
On clusters installed with OpenShift Container Platform 4.12 and above, the serial console is disabled by default and all output is written to the graphical console. You can enable the serial console with the following procedure.
Procedure
-
Download the
coreos-installer
binary from thecoreos-installer
image mirror page. Retrieve the RHCOS ISO image from the RHCOS image mirror page and run the following command to customize the ISO image to enable the serial console to receive output:
$ coreos-installer iso customize rhcos-<version>-live.x86_64.iso \ --dest-ignition <path> \1 --dest-console tty0 \2 --dest-console ttyS0,<options> \3 --dest-device /dev/disk/by-id/scsi-<serial_number> 4
- 1
- The location of the Ignition config to install.
- 2
- The desired secondary console. In this case, the graphical console. Omitting this option will disable the graphical console.
- 3
- The desired primary console. In this case, the serial console. The
options
field defines the baud rate and other settings. A common value for this field is115200n8
. If no options are provided, the default kernel value of9600n8
is used. For more information on the format of this option, see the Linux kernel serial console documentation. - 4
- The specified disk to install to. If you omit this option, the ISO image automatically runs the installation program which will fail unless you also specify the
coreos.inst.install_dev
kernel argument.
NoteThe
--dest-console
option affects the installed system and not the live ISO system. To modify the console for a live ISO system, use the--live-karg-append
option and specify the console withconsole=
.Your customizations are applied and affect every subsequent boot of the ISO image.
Optional: To remove the ISO image customizations and return the image to its original state, run the following command:
$ coreos-installer iso reset rhcos-<version>-live.x86_64.iso
You can now recustomize the live ISO image or use it in its original state.
3.14.3.7.2. Modifying a live install ISO image to use a custom certificate authority
You can provide certificate authority (CA) certificates to Ignition with the --ignition-ca
flag of the customize
subcommand. You can use the CA certificates during both the installation boot and when provisioning the installed system.
Custom CA certificates affect how Ignition fetches remote resources but they do not affect the certificates installed onto the system.
Procedure
-
Download the
coreos-installer
binary from thecoreos-installer
image mirror page. Retrieve the RHCOS ISO image from the RHCOS image mirror page and run the following command to customize the ISO image for use with a custom CA:
$ coreos-installer iso customize rhcos-<version>-live.x86_64.iso --ignition-ca cert.pem
The coreos.inst.ignition_url
kernel parameter does not work with the --ignition-ca
flag. You must use the --dest-ignition
flag to create a customized image for each cluster.
Applying your custom CA certificate affects every subsequent boot of RHCOS.
3.14.3.7.3. Modifying a live install ISO image with customized network settings
You can embed a NetworkManager keyfile into the live ISO image and pass it through to the installed system with the --network-keyfile
flag of the customize
subcommand.
When creating a connection profile, you must use a .nmconnection
filename extension in the filename of the connection profile. If you do not use a .nmconnection
filename extension, the cluster will apply the connection profile to the live environment, but it will not apply the configuration when the cluster first boots up the nodes, resulting in a setup that does not work.
Procedure
-
Download the
coreos-installer
binary from thecoreos-installer
image mirror page. Create a connection profile for a bonded interface. For example, create the
bond0.nmconnection
file in your local directory with the following content:[connection] id=bond0 type=bond interface-name=bond0 multi-connect=1 [bond] miimon=100 mode=active-backup [ipv4] method=auto [ipv6] method=auto
Create a connection profile for a secondary interface to add to the bond. For example, create the
bond0-proxy-em1.nmconnection
file in your local directory with the following content:[connection] id=em1 type=ethernet interface-name=em1 master=bond0 multi-connect=1 slave-type=bond
Create a connection profile for a secondary interface to add to the bond. For example, create the
bond0-proxy-em2.nmconnection
file in your local directory with the following content:[connection] id=em2 type=ethernet interface-name=em2 master=bond0 multi-connect=1 slave-type=bond
Retrieve the RHCOS ISO image from the RHCOS image mirror page and run the following command to customize the ISO image with your configured networking:
$ coreos-installer iso customize rhcos-<version>-live.x86_64.iso \ --network-keyfile bond0.nmconnection \ --network-keyfile bond0-proxy-em1.nmconnection \ --network-keyfile bond0-proxy-em2.nmconnection
Network settings are applied to the live system and are carried over to the destination system.
3.14.3.8. Customizing a live RHCOS PXE environment
You can customize a live RHCOS PXE environment directly with the coreos-installer pxe customize
subcommand. When you boot the PXE environment, the customizations are applied automatically.
You can use this feature to configure the PXE environment to automatically install RHCOS.
Procedure
-
Download the
coreos-installer
binary from thecoreos-installer
image mirror page. Retrieve the RHCOS
kernel
,initramfs
androotfs
files from the RHCOS image mirror page and the Ignition config file, and then run the following command to create a newinitramfs
file that contains the customizations from your Ignition config:$ coreos-installer pxe customize rhcos-<version>-live-initramfs.x86_64.img \ --dest-ignition bootstrap.ign \ 1 --dest-device /dev/disk/by-id/scsi-<serial_number> \ 2 -o rhcos-<version>-custom-initramfs.x86_64.img 3
- 1
- The Ignition config file that is generated from
openshift-installer
. - 2
- When you specify this option, the PXE environment automatically runs an install. Otherwise, the image remains configured for installing, but does not do so automatically unless you specify the
coreos.inst.install_dev
kernel argument. - 3
- Use the customized
initramfs
file in your PXE configuration. Add theignition.firstboot
andignition.platform.id=metal
kernel arguments if they are not already present.
Applying your customizations affects every subsequent boot of RHCOS.
3.14.3.8.1. Modifying a live install PXE environment to enable the serial console
On clusters installed with OpenShift Container Platform 4.12 and above, the serial console is disabled by default and all output is written to the graphical console. You can enable the serial console with the following procedure.
Procedure
-
Download the
coreos-installer
binary from thecoreos-installer
image mirror page. Retrieve the RHCOS
kernel
,initramfs
androotfs
files from the RHCOS image mirror page and the Ignition config file, and then run the following command to create a new customizedinitramfs
file that enables the serial console to receive output:$ coreos-installer pxe customize rhcos-<version>-live-initramfs.x86_64.img \ --dest-ignition <path> \1 --dest-console tty0 \2 --dest-console ttyS0,<options> \3 --dest-device /dev/disk/by-id/scsi-<serial_number> \4 -o rhcos-<version>-custom-initramfs.x86_64.img 5
- 1
- The location of the Ignition config to install.
- 2
- The desired secondary console. In this case, the graphical console. Omitting this option will disable the graphical console.
- 3
- The desired primary console. In this case, the serial console. The
options
field defines the baud rate and other settings. A common value for this field is115200n8
. If no options are provided, the default kernel value of9600n8
is used. For more information on the format of this option, see the Linux kernel serial console documentation. - 4
- The specified disk to install to. If you omit this option, the PXE environment automatically runs the installer which will fail unless you also specify the
coreos.inst.install_dev
kernel argument. - 5
- Use the customized
initramfs
file in your PXE configuration. Add theignition.firstboot
andignition.platform.id=metal
kernel arguments if they are not already present.
Your customizations are applied and affect every subsequent boot of the PXE environment.
3.14.3.8.2. Modifying a live install PXE environment to use a custom certificate authority
You can provide certificate authority (CA) certificates to Ignition with the --ignition-ca
flag of the customize
subcommand. You can use the CA certificates during both the installation boot and when provisioning the installed system.
Custom CA certificates affect how Ignition fetches remote resources but they do not affect the certificates installed onto the system.
Procedure
-
Download the
coreos-installer
binary from thecoreos-installer
image mirror page. Retrieve the RHCOS
kernel
,initramfs
androotfs
files from the RHCOS image mirror page and run the following command to create a new customizedinitramfs
file for use with a custom CA:$ coreos-installer pxe customize rhcos-<version>-live-initramfs.x86_64.img \ --ignition-ca cert.pem \ -o rhcos-<version>-custom-initramfs.x86_64.img
-
Use the customized
initramfs
file in your PXE configuration. Add theignition.firstboot
andignition.platform.id=metal
kernel arguments if they are not already present.
The coreos.inst.ignition_url
kernel parameter does not work with the --ignition-ca
flag. You must use the --dest-ignition
flag to create a customized image for each cluster.
Applying your custom CA certificate affects every subsequent boot of RHCOS.
3.14.3.8.3. Modifying a live install PXE environment with customized network settings
You can embed a NetworkManager keyfile into the live PXE environment and pass it through to the installed system with the --network-keyfile
flag of the customize
subcommand.
When creating a connection profile, you must use a .nmconnection
filename extension in the filename of the connection profile. If you do not use a .nmconnection
filename extension, the cluster will apply the connection profile to the live environment, but it will not apply the configuration when the cluster first boots up the nodes, resulting in a setup that does not work.
Procedure
-
Download the
coreos-installer
binary from thecoreos-installer
image mirror page. Create a connection profile for a bonded interface. For example, create the
bond0.nmconnection
file in your local directory with the following content:[connection] id=bond0 type=bond interface-name=bond0 multi-connect=1 [bond] miimon=100 mode=active-backup [ipv4] method=auto [ipv6] method=auto
Create a connection profile for a secondary interface to add to the bond. For example, create the
bond0-proxy-em1.nmconnection
file in your local directory with the following content:[connection] id=em1 type=ethernet interface-name=em1 master=bond0 multi-connect=1 slave-type=bond
Create a connection profile for a secondary interface to add to the bond. For example, create the
bond0-proxy-em2.nmconnection
file in your local directory with the following content:[connection] id=em2 type=ethernet interface-name=em2 master=bond0 multi-connect=1 slave-type=bond
Retrieve the RHCOS
kernel
,initramfs
androotfs
files from the RHCOS image mirror page and run the following command to create a new customizedinitramfs
file that contains your configured networking:$ coreos-installer pxe customize rhcos-<version>-live-initramfs.x86_64.img \ --network-keyfile bond0.nmconnection \ --network-keyfile bond0-proxy-em1.nmconnection \ --network-keyfile bond0-proxy-em2.nmconnection \ -o rhcos-<version>-custom-initramfs.x86_64.img
Use the customized
initramfs
file in your PXE configuration. Add theignition.firstboot
andignition.platform.id=metal
kernel arguments if they are not already present.Network settings are applied to the live system and are carried over to the destination system.
3.14.3.9. Advanced RHCOS installation reference
This section illustrates the networking configuration and other advanced options that allow you to modify the Red Hat Enterprise Linux CoreOS (RHCOS) manual installation process. The following tables describe the kernel arguments and command-line options you can use with the RHCOS live installer and the coreos-installer
command.
3.14.3.9.1. Networking and bonding options for ISO installations
If you install RHCOS from an ISO image, you can add kernel arguments manually when you boot the image to configure networking for a node. If no networking arguments are specified, DHCP is activated in the initramfs when RHCOS detects that networking is required to fetch the Ignition config file.
When adding networking arguments manually, you must also add the rd.neednet=1
kernel argument to bring the network up in the initramfs.
The following information provides examples for configuring networking and bonding on your RHCOS nodes for ISO installations. The examples describe how to use the ip=
, nameserver=
, and bond=
kernel arguments.
Ordering is important when adding the kernel arguments: ip=
, nameserver=
, and then bond=
.
The networking options are passed to the dracut
tool during system boot. For more information about the networking options supported by dracut
, see the dracut.cmdline
manual page.
The following examples are the networking options for ISO installation.
Configuring DHCP or static IP addresses
To configure an IP address, either use DHCP (ip=dhcp
) or set an individual static IP address (ip=<host_ip>
). If setting a static IP, you must then identify the DNS server IP address (nameserver=<dns_ip>
) on each node. The following example sets:
-
The node’s IP address to
10.10.10.2
-
The gateway address to
10.10.10.254
-
The netmask to
255.255.255.0
-
The hostname to
core0.example.com
-
The DNS server address to
4.4.4.41
-
The auto-configuration value to
none
. No auto-configuration is required when IP networking is configured statically.
ip=10.10.10.2::10.10.10.254:255.255.255.0:core0.example.com:enp1s0:none nameserver=4.4.4.41
When you use DHCP to configure IP addressing for the RHCOS machines, the machines also obtain the DNS server information through DHCP. For DHCP-based deployments, you can define the DNS server address that is used by the RHCOS nodes through your DHCP server configuration.
Configuring an IP address without a static hostname
You can configure an IP address without assigning a static hostname. If a static hostname is not set by the user, it will be picked up and automatically set by a reverse DNS lookup. To configure an IP address without a static hostname refer to the following example:
-
The node’s IP address to
10.10.10.2
-
The gateway address to
10.10.10.254
-
The netmask to
255.255.255.0
-
The DNS server address to
4.4.4.41
-
The auto-configuration value to
none
. No auto-configuration is required when IP networking is configured statically.
ip=10.10.10.2::10.10.10.254:255.255.255.0::enp1s0:none nameserver=4.4.4.41
Specifying multiple network interfaces
You can specify multiple network interfaces by setting multiple ip=
entries.
ip=10.10.10.2::10.10.10.254:255.255.255.0:core0.example.com:enp1s0:none ip=10.10.10.3::10.10.10.254:255.255.255.0:core0.example.com:enp2s0:none
Configuring default gateway and route
Optional: You can configure routes to additional networks by setting an rd.route=
value.
When you configure one or multiple networks, one default gateway is required. If the additional network gateway is different from the primary network gateway, the default gateway must be the primary network gateway.
Run the following command to configure the default gateway:
ip=::10.10.10.254::::
Enter the following command to configure the route for the additional network:
rd.route=20.20.20.0/24:20.20.20.254:enp2s0
Disabling DHCP on a single interface
You can disable DHCP on a single interface, such as when there are two or more network interfaces and only one interface is being used. In the example, the enp1s0
interface has a static networking configuration and DHCP is disabled for enp2s0
, which is not used:
ip=10.10.10.2::10.10.10.254:255.255.255.0:core0.example.com:enp1s0:none ip=::::core0.example.com:enp2s0:none
Combining DHCP and static IP configurations
You can combine DHCP and static IP configurations on systems with multiple network interfaces, for example:
ip=enp1s0:dhcp ip=10.10.10.2::10.10.10.254:255.255.255.0:core0.example.com:enp2s0:none
Configuring VLANs on individual interfaces
Optional: You can configure VLANs on individual interfaces by using the vlan=
parameter.
To configure a VLAN on a network interface and use a static IP address, run the following command:
ip=10.10.10.2::10.10.10.254:255.255.255.0:core0.example.com:enp2s0.100:none vlan=enp2s0.100:enp2s0
To configure a VLAN on a network interface and to use DHCP, run the following command:
ip=enp2s0.100:dhcp vlan=enp2s0.100:enp2s0
Providing multiple DNS servers
You can provide multiple DNS servers by adding a nameserver=
entry for each server, for example:
nameserver=1.1.1.1 nameserver=8.8.8.8
Bonding multiple network interfaces to a single interface
Optional: You can bond multiple network interfaces to a single interface by using the bond=
option. Refer to the following examples:
The syntax for configuring a bonded interface is:
bond=<name>[:<network_interfaces>][:options]
<name>
is the bonding device name (bond0
),<network_interfaces>
represents a comma-separated list of physical (ethernet) interfaces (em1,em2
), and options is a comma-separated list of bonding options. Entermodinfo bonding
to see available options.When you create a bonded interface using
bond=
, you must specify how the IP address is assigned and other information for the bonded interface.To configure the bonded interface to use DHCP, set the bond’s IP address to
dhcp
. For example:bond=bond0:em1,em2:mode=active-backup ip=bond0:dhcp
To configure the bonded interface to use a static IP address, enter the specific IP address you want and related information. For example:
bond=bond0:em1,em2:mode=active-backup ip=10.10.10.2::10.10.10.254:255.255.255.0:core0.example.com:bond0:none
Bonding multiple SR-IOV network interfaces to a dual port NIC interface
Support for Day 1 operations associated with enabling NIC partitioning for SR-IOV devices is a Technology Preview feature only. Technology Preview features are not supported with Red Hat production service level agreements (SLAs) and might not be functionally complete. Red Hat does not recommend using them in production. These features provide early access to upcoming product features, enabling customers to test functionality and provide feedback during the development process.
For more information about the support scope of Red Hat Technology Preview features, see Technology Preview Features Support Scope.
Optional: You can bond multiple SR-IOV network interfaces to a dual port NIC interface by using the bond=
option.
On each node, you must perform the following tasks:
- Create the SR-IOV virtual functions (VFs) following the guidance in Managing SR-IOV devices. Follow the procedure in the "Attaching SR-IOV networking devices to virtual machines" section.
- Create the bond, attach the desired VFs to the bond and set the bond link state up following the guidance in Configuring network bonding. Follow any of the described procedures to create the bond.
The following examples illustrate the syntax you must use:
The syntax for configuring a bonded interface is
bond=<name>[:<network_interfaces>][:options]
.<name>
is the bonding device name (bond0
),<network_interfaces>
represents the virtual functions (VFs) by their known name in the kernel and shown in the output of theip link
command(eno1f0
,eno2f0
), and options is a comma-separated list of bonding options. Entermodinfo bonding
to see available options.When you create a bonded interface using
bond=
, you must specify how the IP address is assigned and other information for the bonded interface.To configure the bonded interface to use DHCP, set the bond’s IP address to
dhcp
. For example:bond=bond0:eno1f0,eno2f0:mode=active-backup ip=bond0:dhcp
To configure the bonded interface to use a static IP address, enter the specific IP address you want and related information. For example:
bond=bond0:eno1f0,eno2f0:mode=active-backup ip=10.10.10.2::10.10.10.254:255.255.255.0:core0.example.com:bond0:none
Using network teaming
Optional: You can use a network teaming as an alternative to bonding by using the team=
parameter:
The syntax for configuring a team interface is:
team=name[:network_interfaces]
name is the team device name (
team0
) and network_interfaces represents a comma-separated list of physical (ethernet) interfaces (em1, em2
).
Teaming is planned to be deprecated when RHCOS switches to an upcoming version of RHEL. For more information, see this Red Hat Knowledgebase Article.
Use the following example to configure a network team:
team=team0:em1,em2 ip=team0:dhcp
3.14.3.9.2. coreos-installer
options for ISO and PXE installations
You can install RHCOS by running coreos-installer install <options> <device>
at the command prompt, after booting into the RHCOS live environment from an ISO image.
The following table shows the subcommands, options, and arguments you can pass to the coreos-installer
command.
coreos-installer install subcommand | |
Subcommand | Description |
| Embed an Ignition config in an ISO image. |
coreos-installer install subcommand options | |
Option | Description |
| Specify the image URL manually. |
| Specify a local image file manually. Used for debugging. |
| Embed an Ignition config from a file. |
| Embed an Ignition config from a URL. |
|
Digest |
| Override the Ignition platform ID for the installed system. |
|
Set the kernel and bootloader console for the installed system. For more information about the format of |
| Append a default kernel argument to the installed system. |
| Delete a default kernel argument from the installed system. |
| Copy the network configuration from the install environment. Important
The |
|
For use with |
| Save partitions with this label glob. |
| Save partitions with this number or range. |
| Skip RHCOS image signature verification. |
| Allow Ignition URL without HTTPS or hash. |
|
Target CPU architecture. Valid values are |
| Do not clear partition table on error. |
| Print help information. |
coreos-installer install subcommand argument | |
Argument | Description |
| The destination device. |
coreos-installer ISO subcommands | |
Subcommand | Description |
| Customize a RHCOS live ISO image. |
| Restore a RHCOS live ISO image to default settings. |
| Remove the embedded Ignition config from an ISO image. |
coreos-installer ISO customize subcommand options | |
Option | Description |
| Merge the specified Ignition config file into a new configuration fragment for the destination system. |
| Specify the kernel and bootloader console for the destination system. |
| Install and overwrite the specified destination device. |
| Add a kernel argument to each boot of the destination system. |
| Delete a kernel argument from each boot of the destination system. |
| Configure networking by using the specified NetworkManager keyfile for live and destination systems. |
| Specify an additional TLS certificate authority to be trusted by Ignition. |
| Run the specified script before installation. |
| Run the specified script after installation. |
| Apply the specified installer configuration file. |
| Merge the specified Ignition config file into a new configuration fragment for the live environment. |
| Add a kernel argument to each boot of the live environment. |
| Delete a kernel argument from each boot of the live environment. |
|
Replace a kernel argument in each boot of the live environment, in the form |
| Overwrite an existing Ignition config. |
| Write the ISO to a new output file. |
| Print help information. |
coreos-installer PXE subcommands | |
Subcommand | Description |
Note that not all of these options are accepted by all subcommands. | |
| Customize a RHCOS live PXE boot config. |
| Wrap an Ignition config in an image. |
| Show the wrapped Ignition config in an image. |
coreos-installer PXE customize subcommand options | |
Option | Description |
Note that not all of these options are accepted by all subcommands. | |
| Merge the specified Ignition config file into a new configuration fragment for the destination system. |
| Specify the kernel and bootloader console for the destination system. |
| Install and overwrite the specified destination device. |
| Configure networking by using the specified NetworkManager keyfile for live and destination systems. |
| Specify an additional TLS certificate authority to be trusted by Ignition. |
| Run the specified script before installation. |
| Run the specified script after installation. |
| Apply the specified installer configuration file. |
| Merge the specified Ignition config file into a new configuration fragment for the live environment. |
| Write the initramfs to a new output file. Note This option is required for PXE environments. |
| Print help information. |
3.14.3.9.3. coreos.inst
boot options for ISO or PXE installations
You can automatically invoke coreos-installer
options at boot time by passing coreos.inst
boot arguments to the RHCOS live installer. These are provided in addition to the standard boot arguments.
-
For ISO installations, the
coreos.inst
options can be added by interrupting the automatic boot at the bootloader menu. You can interrupt the automatic boot by pressingTAB
while the RHEL CoreOS (Live) menu option is highlighted. -
For PXE or iPXE installations, the
coreos.inst
options must be added to theAPPEND
line before the RHCOS live installer is booted.
The following table shows the RHCOS live installer coreos.inst
boot options for ISO and PXE installations.
Argument | Description |
---|---|
|
Required. The block device on the system to install to. It is recommended to use the full path, such as |
| Optional: The URL of the Ignition config to embed into the installed system. If no URL is specified, no Ignition config is embedded. Only HTTP and HTTPS protocols are supported. |
| Optional: Comma-separated labels of partitions to preserve during the install. Glob-style wildcards are permitted. The specified partitions do not need to exist. |
|
Optional: Comma-separated indexes of partitions to preserve during the install. Ranges |
|
Optional: Permits the OS image that is specified by |
| Optional: Download and install the specified RHCOS image.
|
| Optional: The system will not reboot after installing. After the install finishes, you will receive a prompt that allows you to inspect what is happening during installation. This argument should not be used in production environments and is intended for debugging purposes only. |
|
Optional: The Ignition platform ID of the platform the RHCOS image is being installed on. Default is |
|
Optional: The URL of the Ignition config for the live boot. For example, this can be used to customize how |
3.14.4. Enabling multipathing with kernel arguments on RHCOS
RHCOS supports multipathing on the primary disk, allowing stronger resilience to hardware failure to achieve higher host availability.
You can enable multipathing at installation time for nodes that were provisioned in OpenShift Container Platform 4.8 or later. While postinstallation support is available by activating multipathing via the machine config, enabling multipathing during installation is recommended.
In setups where any I/O to non-optimized paths results in I/O system errors, you must enable multipathing at installation time.
On IBM Z and IBM® LinuxONE, you can enable multipathing only if you configured your cluster for it during installation. For more information, see "Installing RHCOS and starting the OpenShift Container Platform bootstrap process" in Installing a cluster with z/VM on IBM Z and IBM® LinuxONE.
The following procedure enables multipath at installation time and appends kernel arguments to the coreos-installer install
command so that the installed system itself will use multipath beginning from the first boot.
OpenShift Container Platform does not support enabling multipathing as a day-2 activity on nodes that have been upgraded from 4.6 or earlier.
Prerequisites
- You have created the Ignition config files for your cluster.
- You have reviewed Installing RHCOS and starting the OpenShift Container Platform bootstrap process.
Procedure
To enable multipath and start the
multipathd
daemon, run the following command on the installation host:$ mpathconf --enable && systemctl start multipathd.service
-
Optional: If booting the PXE or ISO, you can instead enable multipath by adding
rd.multipath=default
from the kernel command line.
-
Optional: If booting the PXE or ISO, you can instead enable multipath by adding
Append the kernel arguments by invoking the
coreos-installer
program:If there is only one multipath device connected to the machine, it should be available at path
/dev/mapper/mpatha
. For example:$ coreos-installer install /dev/mapper/mpatha \1 --ignition-url=http://host/worker.ign \ --append-karg rd.multipath=default \ --append-karg root=/dev/disk/by-label/dm-mpath-root \ --append-karg rw
- 1
- Indicates the path of the single multipathed device.
If there are multiple multipath devices connected to the machine, or to be more explicit, instead of using
/dev/mapper/mpatha
, it is recommended to use the World Wide Name (WWN) symlink available in/dev/disk/by-id
. For example:$ coreos-installer install /dev/disk/by-id/wwn-<wwn_ID> \1 --ignition-url=http://host/worker.ign \ --append-karg rd.multipath=default \ --append-karg root=/dev/disk/by-label/dm-mpath-root \ --append-karg rw
- 1
- Indicates the WWN ID of the target multipathed device. For example,
0xx194e957fcedb4841
.
This symlink can also be used as the
coreos.inst.install_dev
kernel argument when using specialcoreos.inst.*
arguments to direct the live installer. For more information, see "Installing RHCOS and starting the OpenShift Container Platform bootstrap process".
- Reboot into the installed system.
Check that the kernel arguments worked by going to one of the worker nodes and listing the kernel command line arguments (in
/proc/cmdline
on the host):$ oc debug node/ip-10-0-141-105.ec2.internal
Example output
Starting pod/ip-10-0-141-105ec2internal-debug ... To use host binaries, run `chroot /host` sh-4.2# cat /host/proc/cmdline ... rd.multipath=default root=/dev/disk/by-label/dm-mpath-root ... sh-4.2# exit
You should see the added kernel arguments.
3.14.4.1. Enabling multipathing on secondary disks
RHCOS also supports multipathing on a secondary disk. Instead of kernel arguments, you use Ignition to enable multipathing for the secondary disk at installation time.
Prerequisites
- You have read the section Disk partitioning.
- You have read Enabling multipathing with kernel arguments on RHCOS.
- You have installed the Butane utility.
Procedure
Create a Butane config with information similar to the following:
Example
multipath-config.bu
variant: openshift version: 4.13.0 systemd: units: - name: mpath-configure.service enabled: true contents: | [Unit] Description=Configure Multipath on Secondary Disk ConditionFirstBoot=true ConditionPathExists=!/etc/multipath.conf Before=multipathd.service 1 DefaultDependencies=no [Service] Type=oneshot ExecStart=/usr/sbin/mpathconf --enable 2 [Install] WantedBy=multi-user.target - name: mpath-var-lib-container.service enabled: true contents: | [Unit] Description=Set Up Multipath On /var/lib/containers ConditionFirstBoot=true 3 Requires=dev-mapper-mpatha.device After=dev-mapper-mpatha.device After=ostree-remount.service Before=kubelet.service DefaultDependencies=no [Service] 4 Type=oneshot ExecStart=/usr/sbin/mkfs.xfs -L containers -m reflink=1 /dev/mapper/mpatha ExecStart=/usr/bin/mkdir -p /var/lib/containers [Install] WantedBy=multi-user.target - name: var-lib-containers.mount enabled: true contents: | [Unit] Description=Mount /var/lib/containers After=mpath-var-lib-containers.service Before=kubelet.service 5 [Mount] 6 What=/dev/disk/by-label/dm-mpath-containers Where=/var/lib/containers Type=xfs [Install] WantedBy=multi-user.target
- 1
- The configuration must be set before launching the multipath daemon.
- 2
- Starts the
mpathconf
utility. - 3
- This field must be set to the value
true
. - 4
- Creates the filesystem and directory
/var/lib/containers
. - 5
- The device must be mounted before starting any nodes.
- 6
- Mounts the device to the
/var/lib/containers
mount point. This location cannot be a symlink.
Create the Ignition configuration by running the following command:
$ butane --pretty --strict multipath-config.bu > multipath-config.ign
Continue with the rest of the first boot RHCOS installation process.
ImportantDo not add the
rd.multipath
orroot
kernel arguments on the command-line during installation unless the primary disk is also multipathed.
3.15. Waiting for the bootstrap process to complete
The OpenShift Container Platform bootstrap process begins after the cluster nodes first boot into the persistent RHCOS environment that has been installed to disk. The configuration information provided through the Ignition config files is used to initialize the bootstrap process and install OpenShift Container Platform on the machines. You must wait for the bootstrap process to complete.
Prerequisites
- You have created the Ignition config files for your cluster.
- You have configured suitable network, DNS and load balancing infrastructure.
- You have obtained the installation program and generated the Ignition config files for your cluster.
- You installed RHCOS on your cluster machines and provided the Ignition config files that the OpenShift Container Platform installation program generated.
- Your machines have direct internet access or have an HTTP or HTTPS proxy available.
Procedure
Monitor the bootstrap process:
$ ./openshift-install --dir <installation_directory> wait-for bootstrap-complete \ 1 --log-level=info 2
Example output
INFO Waiting up to 30m0s for the Kubernetes API at https://api.test.example.com:6443... INFO API v1.26.0 up INFO Waiting up to 30m0s for bootstrapping to complete... INFO It is now safe to remove the bootstrap resources
The command succeeds when the Kubernetes API server signals that it has been bootstrapped on the control plane machines.
After the bootstrap process is complete, remove the bootstrap machine from the load balancer.
ImportantYou must remove the bootstrap machine from the load balancer at this point. You can also remove or reformat the bootstrap machine itself.
Additional resources
- See Monitoring installation progress for more information about monitoring the installation logs and retrieving diagnostic data if installation issues arise.
3.16. Logging in to the cluster by using the CLI
You can log in to your cluster as a default system user by exporting the cluster kubeconfig
file. The kubeconfig
file contains information about the cluster that is used by the CLI to connect a client to the correct cluster and API server. The file is specific to a cluster and is created during OpenShift Container Platform installation.
Prerequisites
- You deployed an OpenShift Container Platform cluster.
-
You installed the
oc
CLI.
Procedure
Export the
kubeadmin
credentials:$ export KUBECONFIG=<installation_directory>/auth/kubeconfig 1
- 1
- For
<installation_directory>
, specify the path to the directory that you stored the installation files in.
Verify you can run
oc
commands successfully using the exported configuration:$ oc whoami
Example output
system:admin
3.17. Approving the certificate signing requests for your machines
When you add machines to a cluster, two pending certificate signing requests (CSRs) are generated for each machine that you added. You must confirm that these CSRs are approved or, if necessary, approve them yourself. The client requests must be approved first, followed by the server requests.
Prerequisites
- You added machines to your cluster.
Procedure
Confirm that the cluster recognizes the machines:
$ oc get nodes
Example output
NAME STATUS ROLES AGE VERSION master-0 Ready master 63m v1.26.0 master-1 Ready master 63m v1.26.0 master-2 Ready master 64m v1.26.0
The output lists all of the machines that you created.
NoteThe preceding output might not include the compute nodes, also known as worker nodes, until some CSRs are approved.
Review the pending CSRs and ensure that you see the client requests with the
Pending
orApproved
status for each machine that you added to the cluster:$ oc get csr
Example output
NAME AGE REQUESTOR CONDITION csr-8b2br 15m system:serviceaccount:openshift-machine-config-operator:node-bootstrapper Pending csr-8vnps 15m system:serviceaccount:openshift-machine-config-operator:node-bootstrapper Pending ...
In this example, two machines are joining the cluster. You might see more approved CSRs in the list.
If the CSRs were not approved, after all of the pending CSRs for the machines you added are in
Pending
status, approve the CSRs for your cluster machines:NoteBecause the CSRs rotate automatically, approve your CSRs within an hour of adding the machines to the cluster. If you do not approve them within an hour, the certificates will rotate, and more than two certificates will be present for each node. You must approve all of these certificates. After the client CSR is approved, the Kubelet creates a secondary CSR for the serving certificate, which requires manual approval. Then, subsequent serving certificate renewal requests are automatically approved by the
machine-approver
if the Kubelet requests a new certificate with identical parameters.NoteFor clusters running on platforms that are not machine API enabled, such as bare metal and other user-provisioned infrastructure, you must implement a method of automatically approving the kubelet serving certificate requests (CSRs). If a request is not approved, then the
oc exec
,oc rsh
, andoc logs
commands cannot succeed, because a serving certificate is required when the API server connects to the kubelet. Any operation that contacts the Kubelet endpoint requires this certificate approval to be in place. The method must watch for new CSRs, confirm that the CSR was submitted by thenode-bootstrapper
service account in thesystem:node
orsystem:admin
groups, and confirm the identity of the node.To approve them individually, run the following command for each valid CSR:
$ oc adm certificate approve <csr_name> 1
- 1
<csr_name>
is the name of a CSR from the list of current CSRs.
To approve all pending CSRs, run the following command:
$ oc get csr -o go-template='{{range .items}}{{if not .status}}{{.metadata.name}}{{"\n"}}{{end}}{{end}}' | xargs --no-run-if-empty oc adm certificate approve
NoteSome Operators might not become available until some CSRs are approved.
Now that your client requests are approved, you must review the server requests for each machine that you added to the cluster:
$ oc get csr
Example output
NAME AGE REQUESTOR CONDITION csr-bfd72 5m26s system:node:ip-10-0-50-126.us-east-2.compute.internal Pending csr-c57lv 5m26s system:node:ip-10-0-95-157.us-east-2.compute.internal Pending ...
If the remaining CSRs are not approved, and are in the
Pending
status, approve the CSRs for your cluster machines:To approve them individually, run the following command for each valid CSR:
$ oc adm certificate approve <csr_name> 1
- 1
<csr_name>
is the name of a CSR from the list of current CSRs.
To approve all pending CSRs, run the following command:
$ oc get csr -o go-template='{{range .items}}{{if not .status}}{{.metadata.name}}{{"\n"}}{{end}}{{end}}' | xargs oc adm certificate approve
After all client and server CSRs have been approved, the machines have the
Ready
status. Verify this by running the following command:$ oc get nodes
Example output
NAME STATUS ROLES AGE VERSION master-0 Ready master 73m v1.26.0 master-1 Ready master 73m v1.26.0 master-2 Ready master 74m v1.26.0 worker-0 Ready worker 11m v1.26.0 worker-1 Ready worker 11m v1.26.0
NoteIt can take a few minutes after approval of the server CSRs for the machines to transition to the
Ready
status.
Additional information
- For more information on CSRs, see Certificate Signing Requests.
3.18. Initial Operator configuration
After the control plane initializes, you must immediately configure some Operators so that they all become available.
Prerequisites
- Your control plane has initialized.
Procedure
Watch the cluster components come online:
$ watch -n5 oc get clusteroperators
Example output
NAME VERSION AVAILABLE PROGRESSING DEGRADED SINCE authentication 4.13.0 True False False 19m baremetal 4.13.0 True False False 37m cloud-credential 4.13.0 True False False 40m cluster-autoscaler 4.13.0 True False False 37m config-operator 4.13.0 True False False 38m console 4.13.0 True False False 26m csi-snapshot-controller 4.13.0 True False False 37m dns 4.13.0 True False False 37m etcd 4.13.0 True False False 36m image-registry 4.13.0 True False False 31m ingress 4.13.0 True False False 30m insights 4.13.0 True False False 31m kube-apiserver 4.13.0 True False False 26m kube-controller-manager 4.13.0 True False False 36m kube-scheduler 4.13.0 True False False 36m kube-storage-version-migrator 4.13.0 True False False 37m machine-api 4.13.0 True False False 29m machine-approver 4.13.0 True False False 37m machine-config 4.13.0 True False False 36m marketplace 4.13.0 True False False 37m monitoring 4.13.0 True False False 29m network 4.13.0 True False False 38m node-tuning 4.13.0 True False False 37m openshift-apiserver 4.13.0 True False False 32m openshift-controller-manager 4.13.0 True False False 30m openshift-samples 4.13.0 True False False 32m operator-lifecycle-manager 4.13.0 True False False 37m operator-lifecycle-manager-catalog 4.13.0 True False False 37m operator-lifecycle-manager-packageserver 4.13.0 True False False 32m service-ca 4.13.0 True False False 38m storage 4.13.0 True False False 37m
- Configure the Operators that are not available.
Additional resources
- See Gathering logs from a failed installation for details about gathering data in the event of a failed OpenShift Container Platform installation.
- See Troubleshooting Operator issues for steps to check Operator pod health across the cluster and gather Operator logs for diagnosis.
3.18.1. Image registry removed during installation
On platforms that do not provide shareable object storage, the OpenShift Image Registry Operator bootstraps itself as Removed
. This allows openshift-installer
to complete installations on these platform types.
After installation, you must edit the Image Registry Operator configuration to switch the managementState
from Removed
to Managed
. When this has completed, you must configure storage.
3.18.2. Image registry storage configuration
The Image Registry Operator is not initially available for platforms that do not provide default storage. After installation, you must configure your registry to use storage so that the Registry Operator is made available.
Instructions are shown for configuring a persistent volume, which is required for production clusters. Where applicable, instructions are shown for configuring an empty directory as the storage location, which is available for only non-production clusters.
Additional instructions are provided for allowing the image registry to use block storage types by using the Recreate
rollout strategy during upgrades.
3.18.3. Configuring block registry storage for bare metal
To allow the image registry to use block storage types during upgrades as a cluster administrator, you can use the Recreate
rollout strategy.
Block storage volumes, or block persistent volumes, are supported but not recommended for use with the image registry on production clusters. An installation where the registry is configured on block storage is not highly available because the registry cannot have more than one replica.
If you choose to use a block storage volume with the image registry, you must use a filesystem persistent volume claim (PVC).
Procedure
Enter the following command to set the image registry storage as a block storage type, patch the registry so that it uses the
Recreate
rollout strategy, and runs with only one (1
) replica:$ oc patch config.imageregistry.operator.openshift.io/cluster --type=merge -p '{"spec":{"rolloutStrategy":"Recreate","replicas":1}}'
Provision the PV for the block storage device, and create a PVC for that volume. The requested block volume uses the ReadWriteOnce (RWO) access mode.
Create a
pvc.yaml
file with the following contents to define a VMware vSpherePersistentVolumeClaim
object:kind: PersistentVolumeClaim apiVersion: v1 metadata: name: image-registry-storage 1 namespace: openshift-image-registry 2 spec: accessModes: - ReadWriteOnce 3 resources: requests: storage: 100Gi 4
- 1
- A unique name that represents the
PersistentVolumeClaim
object. - 2
- The namespace for the
PersistentVolumeClaim
object, which isopenshift-image-registry
. - 3
- The access mode of the persistent volume claim. With
ReadWriteOnce
, the volume can be mounted with read and write permissions by a single node. - 4
- The size of the persistent volume claim.
Enter the following command to create the
PersistentVolumeClaim
object from the file:$ oc create -f pvc.yaml -n openshift-image-registry
Enter the following command to edit the registry configuration so that it references the correct PVC:
$ oc edit config.imageregistry.operator.openshift.io -o yaml
Example output
storage: pvc: claim: 1
- 1
- By creating a custom PVC, you can leave the
claim
field blank for the default automatic creation of animage-registry-storage
PVC.
3.19. Completing installation on user-provisioned infrastructure
After you complete the Operator configuration, you can finish installing the cluster on infrastructure that you provide.
Prerequisites
- Your control plane has initialized.
- You have completed the initial Operator configuration.
Procedure
Confirm that all the cluster components are online with the following command:
$ watch -n5 oc get clusteroperators
Example output
NAME VERSION AVAILABLE PROGRESSING DEGRADED SINCE authentication 4.13.0 True False False 19m baremetal 4.13.0 True False False 37m cloud-credential 4.13.0 True False False 40m cluster-autoscaler 4.13.0 True False False 37m config-operator 4.13.0 True False False 38m console 4.13.0 True False False 26m csi-snapshot-controller 4.13.0 True False False 37m dns 4.13.0 True False False 37m etcd 4.13.0 True False False 36m image-registry 4.13.0 True False False 31m ingress 4.13.0 True False False 30m insights 4.13.0 True False False 31m kube-apiserver 4.13.0 True False False 26m kube-controller-manager 4.13.0 True False False 36m kube-scheduler 4.13.0 True False False 36m kube-storage-version-migrator 4.13.0 True False False 37m machine-api 4.13.0 True False False 29m machine-approver 4.13.0 True False False 37m machine-config 4.13.0 True False False 36m marketplace 4.13.0 True False False 37m monitoring 4.13.0 True False False 29m network 4.13.0 True False False 38m node-tuning 4.13.0 True False False 37m openshift-apiserver 4.13.0 True False False 32m openshift-controller-manager 4.13.0 True False False 30m openshift-samples 4.13.0 True False False 32m operator-lifecycle-manager 4.13.0 True False False 37m operator-lifecycle-manager-catalog 4.13.0 True False False 37m operator-lifecycle-manager-packageserver 4.13.0 True False False 32m service-ca 4.13.0 True False False 38m storage 4.13.0 True False False 37m
Alternatively, the following command notifies you when all of the clusters are available. It also retrieves and displays credentials:
$ ./openshift-install --dir <installation_directory> wait-for install-complete 1
- 1
- For
<installation_directory>
, specify the path to the directory that you stored the installation files in.
Example output
INFO Waiting up to 30m0s for the cluster to initialize...
The command succeeds when the Cluster Version Operator finishes deploying the OpenShift Container Platform cluster from Kubernetes API server.
Important-
The Ignition config files that the installation program generates contain certificates that expire after 24 hours, which are then renewed at that time. If the cluster is shut down before renewing the certificates and the cluster is later restarted after the 24 hours have elapsed, the cluster automatically recovers the expired certificates. The exception is that you must manually approve the pending
node-bootstrapper
certificate signing requests (CSRs) to recover kubelet certificates. See the documentation for Recovering from expired control plane certificates for more information. - It is recommended that you use Ignition config files within 12 hours after they are generated because the 24-hour certificate rotates from 16 to 22 hours after the cluster is installed. By using the Ignition config files within 12 hours, you can avoid installation failure if the certificate update runs during installation.
Confirm that the Kubernetes API server is communicating with the pods.
To view a list of all pods, use the following command:
$ oc get pods --all-namespaces
Example output
NAMESPACE NAME READY STATUS RESTARTS AGE openshift-apiserver-operator openshift-apiserver-operator-85cb746d55-zqhs8 1/1 Running 1 9m openshift-apiserver apiserver-67b9g 1/1 Running 0 3m openshift-apiserver apiserver-ljcmx 1/1 Running 0 1m openshift-apiserver apiserver-z25h4 1/1 Running 0 2m openshift-authentication-operator authentication-operator-69d5d8bf84-vh2n8 1/1 Running 0 5m ...
View the logs for a pod that is listed in the output of the previous command by using the following command:
$ oc logs <pod_name> -n <namespace> 1
- 1
- Specify the pod name and namespace, as shown in the output of the previous command.
If the pod logs display, the Kubernetes API server can communicate with the cluster machines.
For an installation with Fibre Channel Protocol (FCP), additional steps are required to enable multipathing. Do not enable multipathing during installation.
See "Enabling multipathing with kernel arguments on RHCOS" in the Post-installation machine configuration tasks documentation for more information.
3.20. Telemetry access for OpenShift Container Platform
In OpenShift Container Platform 4.13, the Telemetry service, which runs by default to provide metrics about cluster health and the success of updates, requires internet access. If your cluster is connected to the internet, Telemetry runs automatically, and your cluster is registered to OpenShift Cluster Manager Hybrid Cloud Console.
After you confirm that your OpenShift Cluster Manager Hybrid Cloud Console inventory is correct, either maintained automatically by Telemetry or manually by using OpenShift Cluster Manager, use subscription watch to track your OpenShift Container Platform subscriptions at the account or multi-cluster level.
Additional resources
- See About remote health monitoring for more information about the Telemetry service
3.21. Next steps
Chapter 4. Installing a user-provisioned bare metal cluster on a restricted network
In OpenShift Container Platform 4.13, you can install a cluster on bare metal infrastructure that you provision in a restricted network.
While you might be able to follow this procedure to deploy a cluster on virtualized or cloud environments, you must be aware of additional considerations for non-bare metal platforms. Review the information in the guidelines for deploying OpenShift Container Platform on non-tested platforms before you attempt to install an OpenShift Container Platform cluster in such an environment.
4.1. Prerequisites
- You reviewed details about the OpenShift Container Platform installation and update processes.
- You read the documentation on selecting a cluster installation method and preparing it for users.
You created a registry on your mirror host and obtained the
imageContentSources
data for your version of OpenShift Container Platform.ImportantBecause the installation media is on the mirror host, you can use that computer to complete all installation steps.
- You provisioned persistent storage for your cluster. To deploy a private image registry, your storage must provide ReadWriteMany access modes.
If you use a firewall and plan to use the Telemetry service, you configured the firewall to allow the sites that your cluster requires access to.
NoteBe sure to also review this site list if you are configuring a proxy.
4.2. About installations in restricted networks
In OpenShift Container Platform 4.13, you can perform an installation that does not require an active connection to the internet to obtain software components. Restricted network installations can be completed using installer-provisioned infrastructure or user-provisioned infrastructure, depending on the cloud platform to which you are installing the cluster.
If you choose to perform a restricted network installation on a cloud platform, you still require access to its cloud APIs. Some cloud functions, like Amazon Web Service’s Route 53 DNS and IAM services, require internet access. Depending on your network, you might require less internet access for an installation on bare metal hardware, Nutanix, or on VMware vSphere.
To complete a restricted network installation, you must create a registry that mirrors the contents of the OpenShift image registry and contains the installation media. You can create this registry on a mirror host, which can access both the internet and your closed network, or by using other methods that meet your restrictions.
Because of the complexity of the configuration for user-provisioned installations, consider completing a standard user-provisioned infrastructure installation before you attempt a restricted network installation using user-provisioned infrastructure. Completing this test installation might make it easier to isolate and troubleshoot any issues that might arise during your installation in a restricted network.
4.2.1. Additional limits
Clusters in restricted networks have the following additional limitations and restrictions:
-
The
ClusterVersion
status includes anUnable to retrieve available updates
error. - By default, you cannot use the contents of the Developer Catalog because you cannot access the required image stream tags.
4.3. Internet access for OpenShift Container Platform
In OpenShift Container Platform 4.13, you require access to the internet to obtain the images that are necessary to install your cluster.
You must have internet access to:
- Access OpenShift Cluster Manager Hybrid Cloud Console to download the installation program and perform subscription management. If the cluster has internet access and you do not disable Telemetry, that service automatically entitles your cluster.
- Access Quay.io to obtain the packages that are required to install your cluster.
- Obtain the packages that are required to perform cluster updates.
4.4. Requirements for a cluster with user-provisioned infrastructure
For a cluster that contains user-provisioned infrastructure, you must deploy all of the required machines.
This section describes the requirements for deploying OpenShift Container Platform on user-provisioned infrastructure.
4.4.1. Required machines for cluster installation
The smallest OpenShift Container Platform clusters require the following hosts:
Hosts | Description |
---|---|
One temporary bootstrap machine | The cluster requires the bootstrap machine to deploy the OpenShift Container Platform cluster on the three control plane machines. You can remove the bootstrap machine after you install the cluster. |
Three control plane machines | The control plane machines run the Kubernetes and OpenShift Container Platform services that form the control plane. |
At least two compute machines, which are also known as worker machines. | The workloads requested by OpenShift Container Platform users run on the compute machines. |
As an exception, you can run zero compute machines in a bare metal cluster that consists of three control plane machines only. This provides smaller, more resource efficient clusters for cluster administrators and developers to use for testing, development, and production. Running one compute machine is not supported.
To maintain high availability of your cluster, use separate physical hosts for these cluster machines.
The bootstrap and control plane machines must use Red Hat Enterprise Linux CoreOS (RHCOS) as the operating system. However, the compute machines can choose between Red Hat Enterprise Linux CoreOS (RHCOS), Red Hat Enterprise Linux (RHEL) 8.6 and later.
Note that RHCOS is based on Red Hat Enterprise Linux (RHEL) 9.2 and inherits all of its hardware certifications and requirements. See Red Hat Enterprise Linux technology capabilities and limits.
4.4.2. Minimum resource requirements for cluster installation
Each cluster machine must meet the following minimum requirements:
Machine | Operating System | CPU [1] | RAM | Storage | Input/Output Per Second (IOPS)[2] |
---|---|---|---|---|---|
Bootstrap | RHCOS | 4 | 16 GB | 100 GB | 300 |
Control plane | RHCOS | 4 | 16 GB | 100 GB | 300 |
Compute | RHCOS, RHEL 8.6 and later [3] | 2 | 8 GB | 100 GB | 300 |
- One CPU is equivalent to one physical core when simultaneous multithreading (SMT), or Hyper-Threading, is not enabled. When enabled, use the following formula to calculate the corresponding ratio: (threads per core × cores) × sockets = CPUs.
- OpenShift Container Platform and Kubernetes are sensitive to disk performance, and faster storage is recommended, particularly for etcd on the control plane nodes which require a 10 ms p99 fsync duration. Note that on many cloud platforms, storage size and IOPS scale together, so you might need to over-allocate storage volume to obtain sufficient performance.
- As with all user-provisioned installations, if you choose to use RHEL compute machines in your cluster, you take responsibility for all operating system life cycle management and maintenance, including performing system updates, applying patches, and completing all other required tasks. Use of RHEL 7 compute machines is deprecated and has been removed in OpenShift Container Platform 4.10 and later.
As of OpenShift Container Platform version 4.13, RHCOS is based on RHEL version 9.2, which updates the micro-architecture requirements. The following list contains the minimum instruction set architectures (ISA) that each architecture requires:
- x86-64 architecture requires x86-64-v2 ISA
- ARM64 architecture requires ARMv8.0-A ISA
- IBM Power architecture requires Power 9 ISA
- s390x architecture requires z14 ISA
For more information, see RHEL Architectures.
If an instance type for your platform meets the minimum requirements for cluster machines, it is supported to use in OpenShift Container Platform.
Additional resources
4.4.3. Certificate signing requests management
Because your cluster has limited access to automatic machine management when you use infrastructure that you provision, you must provide a mechanism for approving cluster certificate signing requests (CSRs) after installation. The kube-controller-manager
only approves the kubelet client CSRs. The machine-approver
cannot guarantee the validity of a serving certificate that is requested by using kubelet credentials because it cannot confirm that the correct machine issued the request. You must determine and implement a method of verifying the validity of the kubelet serving certificate requests and approving them.
Additional resources
- See Configuring a three-node cluster for details about deploying three-node clusters in bare metal environments.
- See Approving the certificate signing requests for your machines for more information about approving cluster certificate signing requests after installation.
4.4.4. Networking requirements for user-provisioned infrastructure
All the Red Hat Enterprise Linux CoreOS (RHCOS) machines require networking to be configured in initramfs
during boot to fetch their Ignition config files.
During the initial boot, the machines require an IP address configuration that is set either through a DHCP server or statically by providing the required boot options. After a network connection is established, the machines download their Ignition config files from an HTTP or HTTPS server. The Ignition config files are then used to set the exact state of each machine. The Machine Config Operator completes more changes to the machines, such as the application of new certificates or keys, after installation.
It is recommended to use a DHCP server for long-term management of the cluster machines. Ensure that the DHCP server is configured to provide persistent IP addresses, DNS server information, and hostnames to the cluster machines.
If a DHCP service is not available for your user-provisioned infrastructure, you can instead provide the IP networking configuration and the address of the DNS server to the nodes at RHCOS install time. These can be passed as boot arguments if you are installing from an ISO image. See the Installing RHCOS and starting the OpenShift Container Platform bootstrap process section for more information about static IP provisioning and advanced networking options.
The Kubernetes API server must be able to resolve the node names of the cluster machines. If the API servers and worker nodes are in different zones, you can configure a default DNS search zone to allow the API server to resolve the node names. Another supported approach is to always refer to hosts by their fully-qualified domain names in both the node objects and all DNS requests.
4.4.4.1. Setting the cluster node hostnames through DHCP
On Red Hat Enterprise Linux CoreOS (RHCOS) machines, the hostname is set through NetworkManager. By default, the machines obtain their hostname through DHCP. If the hostname is not provided by DHCP, set statically through kernel arguments, or another method, it is obtained through a reverse DNS lookup. Reverse DNS lookup occurs after the network has been initialized on a node and can take time to resolve. Other system services can start prior to this and detect the hostname as localhost
or similar. You can avoid this by using DHCP to provide the hostname for each cluster node.
Additionally, setting the hostnames through DHCP can bypass any manual DNS record name configuration errors in environments that have a DNS split-horizon implementation.
4.4.4.2. Network connectivity requirements
You must configure the network connectivity between machines to allow OpenShift Container Platform cluster components to communicate. Each machine must be able to resolve the hostnames of all other machines in the cluster.
This section provides details about the ports that are required.
Protocol | Port | Description |
---|---|---|
ICMP | N/A | Network reachability tests |
TCP |
| Metrics |
|
Host level services, including the node exporter on ports | |
| The default ports that Kubernetes reserves | |
| openshift-sdn | |
UDP |
| VXLAN |
| Geneve | |
|
Host level services, including the node exporter on ports | |
| IPsec IKE packets | |
| IPsec NAT-T packets | |
|
Network Time Protocol (NTP) on UDP port
If an external NTP time server is configured, you must open UDP port | |
TCP/UDP |
| Kubernetes node port |
ESP | N/A | IPsec Encapsulating Security Payload (ESP) |
Protocol | Port | Description |
---|---|---|
TCP |
| Kubernetes API |
Protocol | Port | Description |
---|---|---|
TCP |
| etcd server and peer ports |
NTP configuration for user-provisioned infrastructure
OpenShift Container Platform clusters are configured to use a public Network Time Protocol (NTP) server by default. If you want to use a local enterprise NTP server, or if your cluster is being deployed in a disconnected network, you can configure the cluster to use a specific time server. For more information, see the documentation for Configuring chrony time service.
If a DHCP server provides NTP server information, the chrony time service on the Red Hat Enterprise Linux CoreOS (RHCOS) machines read the information and can sync the clock with the NTP servers.
Additional resources
4.4.5. User-provisioned DNS requirements
In OpenShift Container Platform deployments, DNS name resolution is required for the following components:
- The Kubernetes API
- The OpenShift Container Platform application wildcard
- The bootstrap, control plane, and compute machines
Reverse DNS resolution is also required for the Kubernetes API, the bootstrap machine, the control plane machines, and the compute machines.
DNS A/AAAA or CNAME records are used for name resolution and PTR records are used for reverse name resolution. The reverse records are important because Red Hat Enterprise Linux CoreOS (RHCOS) uses the reverse records to set the hostnames for all the nodes, unless the hostnames are provided by DHCP. Additionally, the reverse records are used to generate the certificate signing requests (CSR) that OpenShift Container Platform needs to operate.
It is recommended to use a DHCP server to provide the hostnames to each cluster node. See the DHCP recommendations for user-provisioned infrastructure section for more information.
The following DNS records are required for a user-provisioned OpenShift Container Platform cluster and they must be in place before installation. In each record, <cluster_name>
is the cluster name and <base_domain>
is the base domain that you specify in the install-config.yaml
file. A complete DNS record takes the form: <component>.<cluster_name>.<base_domain>.
.
Component | Record | Description |
---|---|---|
Kubernetes API |
| A DNS A/AAAA or CNAME record, and a DNS PTR record, to identify the API load balancer. These records must be resolvable by both clients external to the cluster and from all the nodes within the cluster. |
| A DNS A/AAAA or CNAME record, and a DNS PTR record, to internally identify the API load balancer. These records must be resolvable from all the nodes within the cluster. Important The API server must be able to resolve the worker nodes by the hostnames that are recorded in Kubernetes. If the API server cannot resolve the node names, then proxied API calls can fail, and you cannot retrieve logs from pods. | |
Routes |
| A wildcard DNS A/AAAA or CNAME record that refers to the application ingress load balancer. The application ingress load balancer targets the machines that run the Ingress Controller pods. The Ingress Controller pods run on the compute machines by default. These records must be resolvable by both clients external to the cluster and from all the nodes within the cluster.
For example, |
Bootstrap machine |
| A DNS A/AAAA or CNAME record, and a DNS PTR record, to identify the bootstrap machine. These records must be resolvable by the nodes within the cluster. |
Control plane machines |
| DNS A/AAAA or CNAME records and DNS PTR records to identify each machine for the control plane nodes. These records must be resolvable by the nodes within the cluster. |
Compute machines |
| DNS A/AAAA or CNAME records and DNS PTR records to identify each machine for the worker nodes. These records must be resolvable by the nodes within the cluster. |
In OpenShift Container Platform 4.4 and later, you do not need to specify etcd host and SRV records in your DNS configuration.
You can use the dig
command to verify name and reverse name resolution. See the section on Validating DNS resolution for user-provisioned infrastructure for detailed validation steps.
4.4.5.1. Example DNS configuration for user-provisioned clusters
This section provides A and PTR record configuration samples that meet the DNS requirements for deploying OpenShift Container Platform on user-provisioned infrastructure. The samples are not meant to provide advice for choosing one DNS solution over another.
In the examples, the cluster name is ocp4
and the base domain is example.com
.
Example DNS A record configuration for a user-provisioned cluster
The following example is a BIND zone file that shows sample A records for name resolution in a user-provisioned cluster.
Example 4.1. Sample DNS zone database
$TTL 1W @ IN SOA ns1.example.com. root ( 2019070700 ; serial 3H ; refresh (3 hours) 30M ; retry (30 minutes) 2W ; expiry (2 weeks) 1W ) ; minimum (1 week) IN NS ns1.example.com. IN MX 10 smtp.example.com. ; ; ns1.example.com. IN A 192.168.1.5 smtp.example.com. IN A 192.168.1.5 ; helper.example.com. IN A 192.168.1.5 helper.ocp4.example.com. IN A 192.168.1.5 ; api.ocp4.example.com. IN A 192.168.1.5 1 api-int.ocp4.example.com. IN A 192.168.1.5 2 ; *.apps.ocp4.example.com. IN A 192.168.1.5 3 ; bootstrap.ocp4.example.com. IN A 192.168.1.96 4 ; control-plane0.ocp4.example.com. IN A 192.168.1.97 5 control-plane1.ocp4.example.com. IN A 192.168.1.98 6 control-plane2.ocp4.example.com. IN A 192.168.1.99 7 ; compute0.ocp4.example.com. IN A 192.168.1.11 8 compute1.ocp4.example.com. IN A 192.168.1.7 9 ; ;EOF
- 1
- Provides name resolution for the Kubernetes API. The record refers to the IP address of the API load balancer.
- 2
- Provides name resolution for the Kubernetes API. The record refers to the IP address of the API load balancer and is used for internal cluster communications.
- 3
- Provides name resolution for the wildcard routes. The record refers to the IP address of the application ingress load balancer. The application ingress load balancer targets the machines that run the Ingress Controller pods. The Ingress Controller pods run on the compute machines by default.Note
In the example, the same load balancer is used for the Kubernetes API and application ingress traffic. In production scenarios, you can deploy the API and application ingress load balancers separately so that you can scale the load balancer infrastructure for each in isolation.
- 4
- Provides name resolution for the bootstrap machine.
- 5 6 7
- Provides name resolution for the control plane machines.
- 8 9
- Provides name resolution for the compute machines.
Example DNS PTR record configuration for a user-provisioned cluster
The following example BIND zone file shows sample PTR records for reverse name resolution in a user-provisioned cluster.
Example 4.2. Sample DNS zone database for reverse records
$TTL 1W @ IN SOA ns1.example.com. root ( 2019070700 ; serial 3H ; refresh (3 hours) 30M ; retry (30 minutes) 2W ; expiry (2 weeks) 1W ) ; minimum (1 week) IN NS ns1.example.com. ; 5.1.168.192.in-addr.arpa. IN PTR api.ocp4.example.com. 1 5.1.168.192.in-addr.arpa. IN PTR api-int.ocp4.example.com. 2 ; 96.1.168.192.in-addr.arpa. IN PTR bootstrap.ocp4.example.com. 3 ; 97.1.168.192.in-addr.arpa. IN PTR control-plane0.ocp4.example.com. 4 98.1.168.192.in-addr.arpa. IN PTR control-plane1.ocp4.example.com. 5 99.1.168.192.in-addr.arpa. IN PTR control-plane2.ocp4.example.com. 6 ; 11.1.168.192.in-addr.arpa. IN PTR compute0.ocp4.example.com. 7 7.1.168.192.in-addr.arpa. IN PTR compute1.ocp4.example.com. 8 ; ;EOF
- 1
- Provides reverse DNS resolution for the Kubernetes API. The PTR record refers to the record name of the API load balancer.
- 2
- Provides reverse DNS resolution for the Kubernetes API. The PTR record refers to the record name of the API load balancer and is used for internal cluster communications.
- 3
- Provides reverse DNS resolution for the bootstrap machine.
- 4 5 6
- Provides reverse DNS resolution for the control plane machines.
- 7 8
- Provides reverse DNS resolution for the compute machines.
A PTR record is not required for the OpenShift Container Platform application wildcard.
Additional resources
4.4.6. Load balancing requirements for user-provisioned infrastructure
Before you install OpenShift Container Platform, you must provision the API and application Ingress load balancing infrastructure. In production scenarios, you can deploy the API and application Ingress load balancers separately so that you can scale the load balancer infrastructure for each in isolation.
If you want to deploy the API and application Ingress load balancers with a Red Hat Enterprise Linux (RHEL) instance, you must purchase the RHEL subscription separately.
The load balancing infrastructure must meet the following requirements:
API load balancer: Provides a common endpoint for users, both human and machine, to interact with and configure the platform. Configure the following conditions:
- Layer 4 load balancing only. This can be referred to as Raw TCP or SSL Passthrough mode.
- A stateless load balancing algorithm. The options vary based on the load balancer implementation.
ImportantDo not configure session persistence for an API load balancer. Configuring session persistence for a Kubernetes API server might cause performance issues from excess application traffic for your OpenShift Container Platform cluster and the Kubernetes API that runs inside the cluster.
Configure the following ports on both the front and back of the load balancers:
Table 4.7. API load balancer Port Back-end machines (pool members) Internal External Description 6443
Bootstrap and control plane. You remove the bootstrap machine from the load balancer after the bootstrap machine initializes the cluster control plane. You must configure the
/readyz
endpoint for the API server health check probe.X
X
Kubernetes API server
22623
Bootstrap and control plane. You remove the bootstrap machine from the load balancer after the bootstrap machine initializes the cluster control plane.
X
Machine config server
NoteThe load balancer must be configured to take a maximum of 30 seconds from the time the API server turns off the
/readyz
endpoint to the removal of the API server instance from the pool. Within the time frame after/readyz
returns an error or becomes healthy, the endpoint must have been removed or added. Probing every 5 or 10 seconds, with two successful requests to become healthy and three to become unhealthy, are well-tested values.Application Ingress load balancer: Provides an ingress point for application traffic flowing in from outside the cluster. A working configuration for the Ingress router is required for an OpenShift Container Platform cluster.
Configure the following conditions:
- Layer 4 load balancing only. This can be referred to as Raw TCP or SSL Passthrough mode.
- A connection-based or session-based persistence is recommended, based on the options available and types of applications that will be hosted on the platform.
TipIf the true IP address of the client can be seen by the application Ingress load balancer, enabling source IP-based session persistence can improve performance for applications that use end-to-end TLS encryption.
Configure the following ports on both the front and back of the load balancers:
Table 4.8. Application Ingress load balancer Port Back-end machines (pool members) Internal External Description 443
The machines that run the Ingress Controller pods, compute, or worker, by default.
X
X
HTTPS traffic
80
The machines that run the Ingress Controller pods, compute, or worker, by default.
X
X
HTTP traffic
NoteIf you are deploying a three-node cluster with zero compute nodes, the Ingress Controller pods run on the control plane nodes. In three-node cluster deployments, you must configure your application Ingress load balancer to route HTTP and HTTPS traffic to the control plane nodes.
4.4.6.1. Example load balancer configuration for user-provisioned clusters
This section provides an example API and application Ingress load balancer configuration that meets the load balancing requirements for user-provisioned clusters. The sample is an /etc/haproxy/haproxy.cfg
configuration for an HAProxy load balancer. The example is not meant to provide advice for choosing one load balancing solution over another.
In the example, the same load balancer is used for the Kubernetes API and application ingress traffic. In production scenarios, you can deploy the API and application ingress load balancers separately so that you can scale the load balancer infrastructure for each in isolation.
If you are using HAProxy as a load balancer and SELinux is set to enforcing
, you must ensure that the HAProxy service can bind to the configured TCP port by running setsebool -P haproxy_connect_any=1
.
Example 4.3. Sample API and application Ingress load balancer configuration
global log 127.0.0.1 local2 pidfile /var/run/haproxy.pid maxconn 4000 daemon defaults mode http log global option dontlognull option http-server-close option redispatch retries 3 timeout http-request 10s timeout queue 1m timeout connect 10s timeout client 1m timeout server 1m timeout http-keep-alive 10s timeout check 10s maxconn 3000 listen api-server-6443 1 bind *:6443 mode tcp option httpchk GET /readyz HTTP/1.0 option log-health-checks balance roundrobin server bootstrap bootstrap.ocp4.example.com:6443 verify none check check-ssl inter 10s fall 2 rise 3 backup 2 server master0 master0.ocp4.example.com:6443 weight 1 verify none check check-ssl inter 10s fall 2 rise 3 server master1 master1.ocp4.example.com:6443 weight 1 verify none check check-ssl inter 10s fall 2 rise 3 server master2 master2.ocp4.example.com:6443 weight 1 verify none check check-ssl inter 10s fall 2 rise 3 listen machine-config-server-22623 3 bind *:22623 mode tcp server bootstrap bootstrap.ocp4.example.com:22623 check inter 1s backup 4 server master0 master0.ocp4.example.com:22623 check inter 1s server master1 master1.ocp4.example.com:22623 check inter 1s server master2 master2.ocp4.example.com:22623 check inter 1s listen ingress-router-443 5 bind *:443 mode tcp balance source server worker0 worker0.ocp4.example.com:443 check inter 1s server worker1 worker1.ocp4.example.com:443 check inter 1s listen ingress-router-80 6 bind *:80 mode tcp balance source server worker0 worker0.ocp4.example.com:80 check inter 1s server worker1 worker1.ocp4.example.com:80 check inter 1s
- 1
- Port
6443
handles the Kubernetes API traffic and points to the control plane machines. - 2 4
- The bootstrap entries must be in place before the OpenShift Container Platform cluster installation and they must be removed after the bootstrap process is complete.
- 3
- Port
22623
handles the machine config server traffic and points to the control plane machines. - 5
- Port
443
handles the HTTPS traffic and points to the machines that run the Ingress Controller pods. The Ingress Controller pods run on the compute machines by default. - 6
- Port
80
handles the HTTP traffic and points to the machines that run the Ingress Controller pods. The Ingress Controller pods run on the compute machines by default.NoteIf you are deploying a three-node cluster with zero compute nodes, the Ingress Controller pods run on the control plane nodes. In three-node cluster deployments, you must configure your application Ingress load balancer to route HTTP and HTTPS traffic to the control plane nodes.
If you are using HAProxy as a load balancer, you can check that the haproxy
process is listening on ports 6443
, 22623
, 443
, and 80
by running netstat -nltupe
on the HAProxy node.
4.5. Preparing the user-provisioned infrastructure
Before you install OpenShift Container Platform on user-provisioned infrastructure, you must prepare the underlying infrastructure.
This section provides details about the high-level steps required to set up your cluster infrastructure in preparation for an OpenShift Container Platform installation. This includes configuring IP networking and network connectivity for your cluster nodes, enabling the required ports through your firewall, and setting up the required DNS and load balancing infrastructure.
After preparation, your cluster infrastructure must meet the requirements outlined in the Requirements for a cluster with user-provisioned infrastructure section.
Prerequisites
- You have reviewed the OpenShift Container Platform 4.x Tested Integrations page.
- You have reviewed the infrastructure requirements detailed in the Requirements for a cluster with user-provisioned infrastructure section.
Procedure
If you are using DHCP to provide the IP networking configuration to your cluster nodes, configure your DHCP service.
- Add persistent IP addresses for the nodes to your DHCP server configuration. In your configuration, match the MAC address of the relevant network interface to the intended IP address for each node.
When you use DHCP to configure IP addressing for the cluster machines, the machines also obtain the DNS server information through DHCP. Define the persistent DNS server address that is used by the cluster nodes through your DHCP server configuration.
NoteIf you are not using a DHCP service, you must provide the IP networking configuration and the address of the DNS server to the nodes at RHCOS install time. These can be passed as boot arguments if you are installing from an ISO image. See the Installing RHCOS and starting the OpenShift Container Platform bootstrap process section for more information about static IP provisioning and advanced networking options.
Define the hostnames of your cluster nodes in your DHCP server configuration. See the Setting the cluster node hostnames through DHCP section for details about hostname considerations.
NoteIf you are not using a DHCP service, the cluster nodes obtain their hostname through a reverse DNS lookup.
- Ensure that your network infrastructure provides the required network connectivity between the cluster components. See the Networking requirements for user-provisioned infrastructure section for details about the requirements.
Configure your firewall to enable the ports required for the OpenShift Container Platform cluster components to communicate. See Networking requirements for user-provisioned infrastructure section for details about the ports that are required.
ImportantBy default, port
1936
is accessible for an OpenShift Container Platform cluster, because each control plane node needs access to this port.Avoid using the Ingress load balancer to expose this port, because doing so might result in the exposure of sensitive information, such as statistics and metrics, related to Ingress Controllers.
Setup the required DNS infrastructure for your cluster.
- Configure DNS name resolution for the Kubernetes API, the application wildcard, the bootstrap machine, the control plane machines, and the compute machines.
Configure reverse DNS resolution for the Kubernetes API, the bootstrap machine, the control plane machines, and the compute machines.
See the User-provisioned DNS requirements section for more information about the OpenShift Container Platform DNS requirements.
Validate your DNS configuration.
- From your installation node, run DNS lookups against the record names of the Kubernetes API, the wildcard routes, and the cluster nodes. Validate that the IP addresses in the responses correspond to the correct components.
From your installation node, run reverse DNS lookups against the IP addresses of the load balancer and the cluster nodes. Validate that the record names in the responses correspond to the correct components.
See the Validating DNS resolution for user-provisioned infrastructure section for detailed DNS validation steps.
- Provision the required API and application ingress load balancing infrastructure. See the Load balancing requirements for user-provisioned infrastructure section for more information about the requirements.
Some load balancing solutions require the DNS name resolution for the cluster nodes to be in place before the load balancing is initialized.
Additional resources
- Requirements for a cluster with user-provisioned infrastructure
- Installing RHCOS and starting the OpenShift Container Platform bootstrap process
- Setting the cluster node hostnames through DHCP
- Advanced RHCOS installation configuration
- Networking requirements for user-provisioned infrastructure
- User-provisioned DNS requirements
- Validating DNS resolution for user-provisioned infrastructure
- Load balancing requirements for user-provisioned infrastructure
4.6. Validating DNS resolution for user-provisioned infrastructure
You can validate your DNS configuration before installing OpenShift Container Platform on user-provisioned infrastructure.
The validation steps detailed in this section must succeed before you install your cluster.
Prerequisites
- You have configured the required DNS records for your user-provisioned infrastructure.
Procedure
From your installation node, run DNS lookups against the record names of the Kubernetes API, the wildcard routes, and the cluster nodes. Validate that the IP addresses contained in the responses correspond to the correct components.
Perform a lookup against the Kubernetes API record name. Check that the result points to the IP address of the API load balancer:
$ dig +noall +answer @<nameserver_ip> api.<cluster_name>.<base_domain> 1
- 1
- Replace
<nameserver_ip>
with the IP address of the nameserver,<cluster_name>
with your cluster name, and<base_domain>
with your base domain name.
Example output
api.ocp4.example.com. 604800 IN A 192.168.1.5
Perform a lookup against the Kubernetes internal API record name. Check that the result points to the IP address of the API load balancer:
$ dig +noall +answer @<nameserver_ip> api-int.<cluster_name>.<base_domain>
Example output
api-int.ocp4.example.com. 604800 IN A 192.168.1.5
Test an example
*.apps.<cluster_name>.<base_domain>
DNS wildcard lookup. All of the application wildcard lookups must resolve to the IP address of the application ingress load balancer:$ dig +noall +answer @<nameserver_ip> random.apps.<cluster_name>.<base_domain>
Example output
random.apps.ocp4.example.com. 604800 IN A 192.168.1.5
NoteIn the example outputs, the same load balancer is used for the Kubernetes API and application ingress traffic. In production scenarios, you can deploy the API and application ingress load balancers separately so that you can scale the load balancer infrastructure for each in isolation.
You can replace
random
with another wildcard value. For example, you can query the route to the OpenShift Container Platform console:$ dig +noall +answer @<nameserver_ip> console-openshift-console.apps.<cluster_name>.<base_domain>
Example output
console-openshift-console.apps.ocp4.example.com. 604800 IN A 192.168.1.5
Run a lookup against the bootstrap DNS record name. Check that the result points to the IP address of the bootstrap node:
$ dig +noall +answer @<nameserver_ip> bootstrap.<cluster_name>.<base_domain>
Example output
bootstrap.ocp4.example.com. 604800 IN A 192.168.1.96
- Use this method to perform lookups against the DNS record names for the control plane and compute nodes. Check that the results correspond to the IP addresses of each node.
From your installation node, run reverse DNS lookups against the IP addresses of the load balancer and the cluster nodes. Validate that the record names contained in the responses correspond to the correct components.
Perform a reverse lookup against the IP address of the API load balancer. Check that the response includes the record names for the Kubernetes API and the Kubernetes internal API:
$ dig +noall +answer @<nameserver_ip> -x 192.168.1.5
Example output
5.1.168.192.in-addr.arpa. 604800 IN PTR api-int.ocp4.example.com. 1 5.1.168.192.in-addr.arpa. 604800 IN PTR api.ocp4.example.com. 2
NoteA PTR record is not required for the OpenShift Container Platform application wildcard. No validation step is needed for reverse DNS resolution against the IP address of the application ingress load balancer.
Perform a reverse lookup against the IP address of the bootstrap node. Check that the result points to the DNS record name of the bootstrap node:
$ dig +noall +answer @<nameserver_ip> -x 192.168.1.96
Example output
96.1.168.192.in-addr.arpa. 604800 IN PTR bootstrap.ocp4.example.com.
- Use this method to perform reverse lookups against the IP addresses for the control plane and compute nodes. Check that the results correspond to the DNS record names of each node.
4.7. Generating a key pair for cluster node SSH access
During an OpenShift Container Platform installation, you can provide an SSH public key to the installation program. The key is passed to the Red Hat Enterprise Linux CoreOS (RHCOS) nodes through their Ignition config files and is used to authenticate SSH access to the nodes. The key is added to the ~/.ssh/authorized_keys
list for the core
user on each node, which enables password-less authentication.
After the key is passed to the nodes, you can use the key pair to SSH in to the RHCOS nodes as the user core
. To access the nodes through SSH, the private key identity must be managed by SSH for your local user.
If you want to SSH in to your cluster nodes to perform installation debugging or disaster recovery, you must provide the SSH public key during the installation process. The ./openshift-install gather
command also requires the SSH public key to be in place on the cluster nodes.
Do not skip this procedure in production environments, where disaster recovery and debugging is required.
You must use a local key, not one that you configured with platform-specific approaches such as AWS key pairs.
Procedure
If you do not have an existing SSH key pair on your local machine to use for authentication onto your cluster nodes, create one. For example, on a computer that uses a Linux operating system, run the following command:
$ ssh-keygen -t ed25519 -N '' -f <path>/<file_name> 1
- 1
- Specify the path and file name, such as
~/.ssh/id_ed25519
, of the new SSH key. If you have an existing key pair, ensure your public key is in the your~/.ssh
directory.
View the public SSH key:
$ cat <path>/<file_name>.pub
For example, run the following to view the
~/.ssh/id_ed25519.pub
public key:$ cat ~/.ssh/id_ed25519.pub
Add the SSH private key identity to the SSH agent for your local user, if it has not already been added. SSH agent management of the key is required for password-less SSH authentication onto your cluster nodes, or if you want to use the
./openshift-install gather
command.NoteOn some distributions, default SSH private key identities such as
~/.ssh/id_rsa
and~/.ssh/id_dsa
are managed automatically.If the
ssh-agent
process is not already running for your local user, start it as a background task:$ eval "$(ssh-agent -s)"
Example output
Agent pid 31874
Add your SSH private key to the
ssh-agent
:$ ssh-add <path>/<file_name> 1
- 1
- Specify the path and file name for your SSH private key, such as
~/.ssh/id_ed25519
Example output
Identity added: /home/<you>/<path>/<file_name> (<computer_name>)
Next steps
- When you install OpenShift Container Platform, provide the SSH public key to the installation program. If you install a cluster on infrastructure that you provision, you must provide the key to the installation program.
Additional resources
4.8. Manually creating the installation configuration file
Installing the cluster requires that you manually create the installation configuration file.
Prerequisites
- You have an SSH public key on your local machine to provide to the installation program. The key will be used for SSH authentication onto your cluster nodes for debugging and disaster recovery.
- You have obtained the OpenShift Container Platform installation program and the pull secret for your cluster.
-
Obtain the
imageContentSources
section from the output of the command to mirror the repository. - Obtain the contents of the certificate for your mirror registry.
Procedure
Create an installation directory to store your required installation assets in:
$ mkdir <installation_directory>
ImportantYou must create a directory. Some installation assets, like bootstrap X.509 certificates have short expiration intervals, so you must not reuse an installation directory. If you want to reuse individual files from another cluster installation, you can copy them into your directory. However, the file names for the installation assets might change between releases. Use caution when copying installation files from an earlier OpenShift Container Platform version.
Customize the sample
install-config.yaml
file template that is provided and save it in the<installation_directory>
.NoteYou must name this configuration file
install-config.yaml
.-
Unless you use a registry that RHCOS trusts by default, such as
docker.io
, you must provide the contents of the certificate for your mirror repository in theadditionalTrustBundle
section. In most cases, you must provide the certificate for your mirror. -
You must include the
imageContentSources
section from the output of the command to mirror the repository.
-
Unless you use a registry that RHCOS trusts by default, such as
Back up the
install-config.yaml
file so that you can use it to install multiple clusters.ImportantThe
install-config.yaml
file is consumed during the next step of the installation process. You must back it up now.
4.8.1. Installation configuration parameters
Before you deploy an OpenShift Container Platform cluster, you provide a customized install-config.yaml
installation configuration file that describes the details for your environment.
After installation, you cannot modify these parameters in the install-config.yaml
file.
4.8.1.1. Required configuration parameters
Required installation configuration parameters are described in the following table:
Parameter | Description | Values |
---|---|---|
|
The API version for the | String |
|
The base domain of your cloud provider. The base domain is used to create routes to your OpenShift Container Platform cluster components. The full DNS name for your cluster is a combination of the |
A fully-qualified domain or subdomain name, such as |
|
Kubernetes resource | Object |
|
The name of the cluster. DNS records for the cluster are all subdomains of |
String of lowercase letters and hyphens ( |
|
The configuration for the specific platform upon which to perform the installation: | Object |
| Get a pull secret from the Red Hat OpenShift Cluster Manager to authenticate downloading container images for OpenShift Container Platform components from services such as Quay.io. |
{ "auths":{ "cloud.openshift.com":{ "auth":"b3Blb=", "email":"you@example.com" }, "quay.io":{ "auth":"b3Blb=", "email":"you@example.com" } } } |
4.8.1.2. Network configuration parameters
You can customize your installation configuration based on the requirements of your existing network infrastructure. For example, you can expand the IP address block for the cluster network or provide different IP address blocks than the defaults.
- If you use the Red Hat OpenShift Networking OVN-Kubernetes network plugin, both IPv4 and IPv6 address families are supported.
- If you use the Red Hat OpenShift Networking OpenShift SDN network plugin, only the IPv4 address family is supported.
If you configure your cluster to use both IP address families, review the following requirements:
- Both IP families must use the same network interface for the default gateway.
- Both IP families must have the default gateway.
- You must specify IPv4 and IPv6 addresses in the same order for all network configuration parameters. For example, in the following configuration IPv4 addresses are listed before IPv6 addresses.
networking: clusterNetwork: - cidr: 10.128.0.0/14 hostPrefix: 23 - cidr: fd00:10:128::/56 hostPrefix: 64 serviceNetwork: - 172.30.0.0/16 - fd00:172:16::/112
Globalnet is not supported with Red Hat OpenShift Data Foundation disaster recovery solutions. For regional disaster recovery scenarios, ensure that you use a nonoverlapping range of private IP addresses for the cluster and service networks in each cluster.
Parameter | Description | Values |
---|---|---|
| The configuration for the cluster network. | Object Note
You cannot modify parameters specified by the |
| The Red Hat OpenShift Networking network plugin to install. |
Either |
| The IP address blocks for pods.
The default value is If you specify multiple IP address blocks, the blocks must not overlap. | An array of objects. For example: networking: clusterNetwork: - cidr: 10.128.0.0/14 hostPrefix: 23 - cidr: fd01::/48 hostPrefix: 64 |
|
Required if you use If you use the OpenShift SDN network plugin, specify an IPv4 network. If you use the OVN-Kubernetes network plugin, you can specify IPv4 and IPv6 networks. |
An IP address block in Classless Inter-Domain Routing (CIDR) notation. The prefix length for an IPv4 block is between |
|
The subnet prefix length to assign to each individual node. For example, if | A subnet prefix.
For an IPv4 network the default value is |
|
The IP address block for services. The default value is The OpenShift SDN and OVN-Kubernetes network plugins support only a single IP address block for the service network. If you use the OVN-Kubernetes network plugin, you can specify an IP address block for both of the IPv4 and IPv6 address families. | An array with an IP address block in CIDR format. For example: networking: serviceNetwork: - 172.30.0.0/16 - fd02::/112 |
| The IP address blocks for machines. If you specify multiple IP address blocks, the blocks must not overlap. | An array of objects. For example: networking: machineNetwork: - cidr: 10.0.0.0/16 |
|
Required if you use | An IP network block in CIDR notation.
For example, Note
Set the |
4.8.1.3. Optional configuration parameters
Optional installation configuration parameters are described in the following table:
Parameter | Description | Values |
---|---|---|
| A PEM-encoded X.509 certificate bundle that is added to the nodes' trusted certificate store. This trust bundle may also be used when a proxy has been configured. | String |
| Controls the installation of optional core cluster components. You can reduce the footprint of your OpenShift Container Platform cluster by disabling optional components. For more information, see the "Cluster capabilities" page in Installing. | String array |
|
Selects an initial set of optional capabilities to enable. Valid values are | String |
|
Extends the set of optional capabilities beyond what you specify in | String array |
| Enables workload partitioning, which isolates OpenShift Container Platform services, cluster management workloads, and infrastructure pods to run on a reserved set of CPUs. Workload partitioning can only be enabled during installation and cannot be disabled after installation. While this field enables workload partitioning, it does not configure workloads to use specific CPUs. For more information, see the Workload partitioning page in the Scalability and Performance section. |
|
| The configuration for the machines that comprise the compute nodes. |
Array of |
|
Determines the instruction set architecture of the machines in the pool. Currently, clusters with varied architectures are not supported. All pools must specify the same architecture. Valid values are | String |
compute: hyperthreading: |
Whether to enable or disable simultaneous multithreading, or Important If you disable simultaneous multithreading, ensure that your capacity planning accounts for the dramatically decreased machine performance. |
|
|
Required if you use |
|
|
Required if you use |
|
| The number of compute machines, which are also known as worker machines, to provision. |
A positive integer greater than or equal to |
| Enables the cluster for a feature set. A feature set is a collection of OpenShift Container Platform features that are not enabled by default. For more information about enabling a feature set during installation, see "Enabling features using feature gates". |
String. The name of the feature set to enable, such as |
| The configuration for the machines that comprise the control plane. |
Array of |
|
Determines the instruction set architecture of the machines in the pool. Currently, clusters with varied architectures are not supported. All pools must specify the same architecture. Valid values are | String |
controlPlane: hyperthreading: |
Whether to enable or disable simultaneous multithreading, or Important If you disable simultaneous multithreading, ensure that your capacity planning accounts for the dramatically decreased machine performance. |
|
|
Required if you use |
|
|
Required if you use |
|
| The number of control plane machines to provision. |
The only supported value is |
| The Cloud Credential Operator (CCO) mode. If no mode is specified, the CCO dynamically tries to determine the capabilities of the provided credentials, with a preference for mint mode on the platforms where multiple modes are supported. Note Not all CCO modes are supported for all cloud providers. For more information about CCO modes, see the Cloud Credential Operator entry in the Cluster Operators reference content. Note
If your AWS account has service control policies (SCP) enabled, you must configure the |
|
| Sources and repositories for the release-image content. |
Array of objects. Includes a |
|
Required if you use | String |
| Specify one or more repositories that may also contain the same images. | Array of strings |
| How to publish or expose the user-facing endpoints of your cluster, such as the Kubernetes API, OpenShift routes. |
Setting this field to Important
If the value of the field is set to |
| The SSH key to authenticate access to your cluster machines. Note
For production OpenShift Container Platform clusters on which you want to perform installation debugging or disaster recovery, specify an SSH key that your |
For example, |
- Not all CCO modes are supported for all cloud providers. For more information about CCO modes, see the "Managing cloud provider credentials" entry in the Authentication and authorization content.
4.8.2. Sample install-config.yaml file for bare metal
You can customize the install-config.yaml
file to specify more details about your OpenShift Container Platform cluster’s platform or modify the values of the required parameters.
apiVersion: v1 baseDomain: example.com 1 compute: 2 - hyperthreading: Enabled 3 name: worker replicas: 0 4 controlPlane: 5 hyperthreading: Enabled 6 name: master replicas: 3 7 metadata: name: test 8 networking: clusterNetwork: - cidr: 10.128.0.0/14 9 hostPrefix: 23 10 networkType: OVNKubernetes 11 serviceNetwork: 12 - 172.30.0.0/16 platform: none: {} 13 fips: false 14 pullSecret: '{"auths":{"<local_registry>": {"auth": "<credentials>","email": "you@example.com"}}}' 15 sshKey: 'ssh-ed25519 AAAA...' 16 additionalTrustBundle: | 17 -----BEGIN CERTIFICATE----- ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ -----END CERTIFICATE----- imageContentSources: 18 - mirrors: - <local_registry>/<local_repository_name>/release source: quay.io/openshift-release-dev/ocp-release - mirrors: - <local_registry>/<local_repository_name>/release source: quay.io/openshift-release-dev/ocp-v4.0-art-dev
- 1
- The base domain of the cluster. All DNS records must be sub-domains of this base and include the cluster name.
- 2 5
- The
controlPlane
section is a single mapping, but thecompute
section is a sequence of mappings. To meet the requirements of the different data structures, the first line of thecompute
section must begin with a hyphen,-
, and the first line of thecontrolPlane
section must not. Only one control plane pool is used. - 3 6
- Specifies whether to enable or disable simultaneous multithreading (SMT), or hyperthreading. By default, SMT is enabled to increase the performance of the cores in your machines. You can disable it by setting the parameter value to
Disabled
. If you disable SMT, you must disable it in all cluster machines; this includes both control plane and compute machines.NoteSimultaneous multithreading (SMT) is enabled by default. If SMT is not enabled in your BIOS settings, the
hyperthreading
parameter has no effect.ImportantIf you disable
hyperthreading
, whether in the BIOS or in theinstall-config.yaml
file, ensure that your capacity planning accounts for the dramatically decreased machine performance. - 4
- You must set this value to
0
when you install OpenShift Container Platform on user-provisioned infrastructure. In installer-provisioned installations, the parameter controls the number of compute machines that the cluster creates and manages for you. In user-provisioned installations, you must manually deploy the compute machines before you finish installing the cluster.NoteIf you are installing a three-node cluster, do not deploy any compute machines when you install the Red Hat Enterprise Linux CoreOS (RHCOS) machines.
- 7
- The number of control plane machines that you add to the cluster. Because the cluster uses these values as the number of etcd endpoints in the cluster, the value must match the number of control plane machines that you deploy.
- 8
- The cluster name that you specified in your DNS records.
- 9
- A block of IP addresses from which pod IP addresses are allocated. This block must not overlap with existing physical networks. These IP addresses are used for the pod network. If you need to access the pods from an external network, you must configure load balancers and routers to manage the traffic.Note
Class E CIDR range is reserved for a future use. To use the Class E CIDR range, you must ensure your networking environment accepts the IP addresses within the Class E CIDR range.
- 10
- The subnet prefix length to assign to each individual node. For example, if
hostPrefix
is set to23
, then each node is assigned a/23
subnet out of the givencidr
, which allows for 510 (2^(32 - 23) - 2) pod IP addresses. If you are required to provide access to nodes from an external network, configure load balancers and routers to manage the traffic. - 11
- The cluster network plugin to install. The supported values are
OVNKubernetes
andOpenShiftSDN
. The default value isOVNKubernetes
. - 12
- The IP address pool to use for service IP addresses. You can enter only one IP address pool. This block must not overlap with existing physical networks. If you need to access the services from an external network, configure load balancers and routers to manage the traffic.
- 13
- You must set the platform to
none
. You cannot provide additional platform configuration variables for your platform.ImportantClusters that are installed with the platform type
none
are unable to use some features, such as managing compute machines with the Machine API. This limitation applies even if the compute machines that are attached to the cluster are installed on a platform that would normally support the feature. This parameter cannot be changed after installation. - 14
- Whether to enable or disable FIPS mode. By default, FIPS mode is not enabled.Important
OpenShift Container Platform 4.13 is based on Red Hat Enterprise Linux (RHEL) 9.2. RHEL 9.2 cryptographic modules have not yet been submitted for FIPS validation. For more information, see "About this release" in the 4.13 OpenShift Container Platform Release Notes.
- 15
- For
<local_registry>
, specify the registry domain name, and optionally the port, that your mirror registry uses to serve content. For example,registry.example.com
orregistry.example.com:5000
. For<credentials>
, specify the base64-encoded user name and password for your mirror registry. - 16
- The SSH public key for the
core
user in Red Hat Enterprise Linux CoreOS (RHCOS).NoteFor production OpenShift Container Platform clusters on which you want to perform installation debugging or disaster recovery, specify an SSH key that your
ssh-agent
process uses. - 17
- Provide the contents of the certificate file that you used for your mirror registry.
- 18
- Provide the
imageContentSources
section from the output of the command to mirror the repository.
Additional resources
- See Load balancing requirements for user-provisioned infrastructure for more information on the API and application ingress load balancing requirements.
4.8.3. Configuring the cluster-wide proxy during installation
Production environments can deny direct access to the internet and instead have an HTTP or HTTPS proxy available. You can configure a new OpenShift Container Platform cluster to use a proxy by configuring the proxy settings in the install-config.yaml
file.
For bare metal installations, if you do not assign node IP addresses from the range that is specified in the networking.machineNetwork[].cidr
field in the install-config.yaml
file, you must include them in the proxy.noProxy
field.
Prerequisites
-
You have an existing
install-config.yaml
file. You reviewed the sites that your cluster requires access to and determined whether any of them need to bypass the proxy. By default, all cluster egress traffic is proxied, including calls to hosting cloud provider APIs. You added sites to the
Proxy
object’sspec.noProxy
field to bypass the proxy if necessary.NoteThe
Proxy
objectstatus.noProxy
field is populated with the values of thenetworking.machineNetwork[].cidr
,networking.clusterNetwork[].cidr
, andnetworking.serviceNetwork[]
fields from your installation configuration.For installations on Amazon Web Services (AWS), Google Cloud Platform (GCP), Microsoft Azure, and Red Hat OpenStack Platform (RHOSP), the
Proxy
objectstatus.noProxy
field is also populated with the instance metadata endpoint (169.254.169.254
).
Procedure
Edit your
install-config.yaml
file and add the proxy settings. For example:apiVersion: v1 baseDomain: my.domain.com proxy: httpProxy: http://<username>:<pswd>@<ip>:<port> 1 httpsProxy: https://<username>:<pswd>@<ip>:<port> 2 noProxy: example.com 3 additionalTrustBundle: | 4 -----BEGIN CERTIFICATE----- <MY_TRUSTED_CA_CERT> -----END CERTIFICATE----- additionalTrustBundlePolicy: <policy_to_add_additionalTrustBundle> 5
- 1
- A proxy URL to use for creating HTTP connections outside the cluster. The URL scheme must be
http
. - 2
- A proxy URL to use for creating HTTPS connections outside the cluster.
- 3
- A comma-separated list of destination domain names, IP addresses, or other network CIDRs to exclude from proxying. Preface a domain with
.
to match subdomains only. For example,.y.com
matchesx.y.com
, but noty.com
. Use*
to bypass the proxy for all destinations. - 4
- If provided, the installation program generates a config map that is named
user-ca-bundle
in theopenshift-config
namespace that contains one or more additional CA certificates that are required for proxying HTTPS connections. The Cluster Network Operator then creates atrusted-ca-bundle
config map that merges these contents with the Red Hat Enterprise Linux CoreOS (RHCOS) trust bundle, and this config map is referenced in thetrustedCA
field of theProxy
object. TheadditionalTrustBundle
field is required unless the proxy’s identity certificate is signed by an authority from the RHCOS trust bundle. - 5
- Optional: The policy to determine the configuration of the
Proxy
object to reference theuser-ca-bundle
config map in thetrustedCA
field. The allowed values areProxyonly
andAlways
. UseProxyonly
to reference theuser-ca-bundle
config map only whenhttp/https
proxy is configured. UseAlways
to always reference theuser-ca-bundle
config map. The default value isProxyonly
.
NoteThe installation program does not support the proxy
readinessEndpoints
field.NoteIf the installer times out, restart and then complete the deployment by using the
wait-for
command of the installer. For example:$ ./openshift-install wait-for install-complete --log-level debug
- Save the file and reference it when installing OpenShift Container Platform.
The installation program creates a cluster-wide proxy that is named cluster
that uses the proxy settings in the provided install-config.yaml
file. If no proxy settings are provided, a cluster
Proxy
object is still created, but it will have a nil spec
.
Only the Proxy
object named cluster
is supported, and no additional proxies can be created.
4.8.4. Configuring a three-node cluster
Optionally, you can deploy zero compute machines in a bare metal cluster that consists of three control plane machines only. This provides smaller, more resource efficient clusters for cluster administrators and developers to use for testing, development, and production.
In three-node OpenShift Container Platform environments, the three control plane machines are schedulable, which means that your application workloads are scheduled to run on them.
Prerequisites
-
You have an existing
install-config.yaml
file.
Procedure
Ensure that the number of compute replicas is set to
0
in yourinstall-config.yaml
file, as shown in the followingcompute
stanza:compute: - name: worker platform: {} replicas: 0
NoteYou must set the value of the
replicas
parameter for the compute machines to0
when you install OpenShift Container Platform on user-provisioned infrastructure, regardless of the number of compute machines you are deploying. In installer-provisioned installations, the parameter controls the number of compute machines that the cluster creates and manages for you. This does not apply to user-provisioned installations, where the compute machines are deployed manually.
For three-node cluster installations, follow these next steps:
- If you are deploying a three-node cluster with zero compute nodes, the Ingress Controller pods run on the control plane nodes. In three-node cluster deployments, you must configure your application ingress load balancer to route HTTP and HTTPS traffic to the control plane nodes. See the Load balancing requirements for user-provisioned infrastructure section for more information.
-
When you create the Kubernetes manifest files in the following procedure, ensure that the
mastersSchedulable
parameter in the<installation_directory>/manifests/cluster-scheduler-02-config.yml
file is set totrue
. This enables your application workloads to run on the control plane nodes. - Do not deploy any compute nodes when you create the Red Hat Enterprise Linux CoreOS (RHCOS) machines.
4.9. Creating the Kubernetes manifest and Ignition config files
Because you must modify some cluster definition files and manually start the cluster machines, you must generate the Kubernetes manifest and Ignition config files that the cluster needs to configure the machines.
The installation configuration file transforms into the Kubernetes manifests. The manifests wrap into the Ignition configuration files, which are later used to configure the cluster machines.
-
The Ignition config files that the OpenShift Container Platform installation program generates contain certificates that expire after 24 hours, which are then renewed at that time. If the cluster is shut down before renewing the certificates and the cluster is later restarted after the 24 hours have elapsed, the cluster automatically recovers the expired certificates. The exception is that you must manually approve the pending
node-bootstrapper
certificate signing requests (CSRs) to recover kubelet certificates. See the documentation for Recovering from expired control plane certificates for more information. - It is recommended that you use Ignition config files within 12 hours after they are generated because the 24-hour certificate rotates from 16 to 22 hours after the cluster is installed. By using the Ignition config files within 12 hours, you can avoid installation failure if the certificate update runs during installation.
Prerequisites
- You obtained the OpenShift Container Platform installation program. For a restricted network installation, these files are on your mirror host.
-
You created the
install-config.yaml
installation configuration file.
Procedure
Change to the directory that contains the OpenShift Container Platform installation program and generate the Kubernetes manifests for the cluster:
$ ./openshift-install create manifests --dir <installation_directory> 1
- 1
- For
<installation_directory>
, specify the installation directory that contains theinstall-config.yaml
file you created.
WarningIf you are installing a three-node cluster, skip the following step to allow the control plane nodes to be schedulable.
ImportantWhen you configure control plane nodes from the default unschedulable to schedulable, additional subscriptions are required. This is because control plane nodes then become compute nodes.
Check that the
mastersSchedulable
parameter in the<installation_directory>/manifests/cluster-scheduler-02-config.yml
Kubernetes manifest file is set tofalse
. This setting prevents pods from being scheduled on the control plane machines:-
Open the
<installation_directory>/manifests/cluster-scheduler-02-config.yml
file. -
Locate the
mastersSchedulable
parameter and ensure that it is set tofalse
. - Save and exit the file.
-
Open the
To create the Ignition configuration files, run the following command from the directory that contains the installation program:
$ ./openshift-install create ignition-configs --dir <installation_directory> 1
- 1
- For
<installation_directory>
, specify the same installation directory.
Ignition config files are created for the bootstrap, control plane, and compute nodes in the installation directory. The
kubeadmin-password
andkubeconfig
files are created in the./<installation_directory>/auth
directory:. ├── auth │ ├── kubeadmin-password │ └── kubeconfig ├── bootstrap.ign ├── master.ign ├── metadata.json └── worker.ign
Additional resources
- See Recovering from expired control plane certificates for more information about recovering kubelet certificates.
4.10. Configuring chrony time service
You must set the time server and related settings used by the chrony time service (chronyd
) by modifying the contents of the chrony.conf
file and passing those contents to your nodes as a machine config.
Procedure
Create a Butane config including the contents of the
chrony.conf
file. For example, to configure chrony on worker nodes, create a99-worker-chrony.bu
file.NoteSee "Creating machine configs with Butane" for information about Butane.
variant: openshift version: 4.13.0 metadata: name: 99-worker-chrony 1 labels: machineconfiguration.openshift.io/role: worker 2 storage: files: - path: /etc/chrony.conf mode: 0644 3 overwrite: true contents: inline: | pool 0.rhel.pool.ntp.org iburst 4 driftfile /var/lib/chrony/drift makestep 1.0 3 rtcsync logdir /var/log/chrony
- 1 2
- On control plane nodes, substitute
master
forworker
in both of these locations. - 3
- Specify an octal value mode for the
mode
field in the machine config file. After creating the file and applying the changes, themode
is converted to a decimal value. You can check the YAML file with the commandoc get mc <mc-name> -o yaml
. - 4
- Specify any valid, reachable time source, such as the one provided by your DHCP server.
Use Butane to generate a
MachineConfig
object file,99-worker-chrony.yaml
, containing the configuration to be delivered to the nodes:$ butane 99-worker-chrony.bu -o 99-worker-chrony.yaml
Apply the configurations in one of two ways:
-
If the cluster is not running yet, after you generate manifest files, add the
MachineConfig
object file to the<installation_directory>/openshift
directory, and then continue to create the cluster. If the cluster is already running, apply the file:
$ oc apply -f ./99-worker-chrony.yaml
-
If the cluster is not running yet, after you generate manifest files, add the
4.11. Installing RHCOS and starting the OpenShift Container Platform bootstrap process
To install OpenShift Container Platform on bare metal infrastructure that you provision, you must install Red Hat Enterprise Linux CoreOS (RHCOS) on the machines. When you install RHCOS, you must provide the Ignition config file that was generated by the OpenShift Container Platform installation program for the type of machine you are installing. If you have configured suitable networking, DNS, and load balancing infrastructure, the OpenShift Container Platform bootstrap process begins automatically after the RHCOS machines have rebooted.
To install RHCOS on the machines, follow either the steps to use an ISO image or network PXE booting.
The compute node deployment steps included in this installation document are RHCOS-specific. If you choose instead to deploy RHEL-based compute nodes, you take responsibility for all operating system life cycle management and maintenance, including performing system updates, applying patches, and completing all other required tasks. Only RHEL 8 compute machines are supported.
You can configure RHCOS during ISO and PXE installations by using the following methods:
-
Kernel arguments: You can use kernel arguments to provide installation-specific information. For example, you can specify the locations of the RHCOS installation files that you uploaded to your HTTP server and the location of the Ignition config file for the type of node you are installing. For a PXE installation, you can use the
APPEND
parameter to pass the arguments to the kernel of the live installer. For an ISO installation, you can interrupt the live installation boot process to add the kernel arguments. In both installation cases, you can use specialcoreos.inst.*
arguments to direct the live installer, as well as standard installation boot arguments for turning standard kernel services on or off. -
Ignition configs: OpenShift Container Platform Ignition config files (
*.ign
) are specific to the type of node you are installing. You pass the location of a bootstrap, control plane, or compute node Ignition config file during the RHCOS installation so that it takes effect on first boot. In special cases, you can create a separate, limited Ignition config to pass to the live system. That Ignition config could do a certain set of tasks, such as reporting success to a provisioning system after completing installation. This special Ignition config is consumed by thecoreos-installer
to be applied on first boot of the installed system. Do not provide the standard control plane and compute node Ignition configs to the live ISO directly. -
coreos-installer
: You can boot the live ISO installer to a shell prompt, which allows you to prepare the permanent system in a variety of ways before first boot. In particular, you can run thecoreos-installer
command to identify various artifacts to include, work with disk partitions, and set up networking. In some cases, you can configure features on the live system and copy them to the installed system.
Whether to use an ISO or PXE install depends on your situation. A PXE install requires an available DHCP service and more preparation, but can make the installation process more automated. An ISO install is a more manual process and can be inconvenient if you are setting up more than a few machines.
As of OpenShift Container Platform 4.6, the RHCOS ISO and other installation artifacts provide support for installation on disks with 4K sectors.
4.11.1. Installing RHCOS by using an ISO image
You can use an ISO image to install RHCOS on the machines.
Prerequisites
- You have created the Ignition config files for your cluster.
- You have configured suitable network, DNS and load balancing infrastructure.
- You have an HTTP server that can be accessed from your computer, and from the machines that you create.
- You have reviewed the Advanced RHCOS installation configuration section for different ways to configure features, such as networking and disk partitioning.
Procedure
Obtain the SHA512 digest for each of your Ignition config files. For example, you can use the following on a system running Linux to get the SHA512 digest for your
bootstrap.ign
Ignition config file:$ sha512sum <installation_directory>/bootstrap.ign
The digests are provided to the
coreos-installer
in a later step to validate the authenticity of the Ignition config files on the cluster nodes.Upload the bootstrap, control plane, and compute node Ignition config files that the installation program created to your HTTP server. Note the URLs of these files.
ImportantYou can add or change configuration settings in your Ignition configs before saving them to your HTTP server. If you plan to add more compute machines to your cluster after you finish installation, do not delete these files.
From the installation host, validate that the Ignition config files are available on the URLs. The following example gets the Ignition config file for the bootstrap node:
$ curl -k http://<HTTP_server>/bootstrap.ign 1
Example output
% Total % Received % Xferd Average Speed Time Time Time Current Dload Upload Total Spent Left Speed 0 0 0 0 0 0 0 0 --:--:-- --:--:-- --:--:-- 0{"ignition":{"version":"3.2.0"},"passwd":{"users":[{"name":"core","sshAuthorizedKeys":["ssh-rsa...
Replace
bootstrap.ign
withmaster.ign
orworker.ign
in the command to validate that the Ignition config files for the control plane and compute nodes are also available.Although it is possible to obtain the RHCOS images that are required for your preferred method of installing operating system instances from the RHCOS image mirror page, the recommended way to obtain the correct version of your RHCOS images are from the output of
openshift-install
command:$ openshift-install coreos print-stream-json | grep '\.iso[^.]'
Example output
"location": "<url>/art/storage/releases/rhcos-4.13-aarch64/<release>/aarch64/rhcos-<release>-live.aarch64.iso", "location": "<url>/art/storage/releases/rhcos-4.13-ppc64le/<release>/ppc64le/rhcos-<release>-live.ppc64le.iso", "location": "<url>/art/storage/releases/rhcos-4.13-s390x/<release>/s390x/rhcos-<release>-live.s390x.iso", "location": "<url>/art/storage/releases/rhcos-4.13/<release>/x86_64/rhcos-<release>-live.x86_64.iso",
ImportantThe RHCOS images might not change with every release of OpenShift Container Platform. You must download images with the highest version that is less than or equal to the OpenShift Container Platform version that you install. Use the image versions that match your OpenShift Container Platform version if they are available. Use only ISO images for this procedure. RHCOS qcow2 images are not supported for this installation type.
ISO file names resemble the following example:
rhcos-<version>-live.<architecture>.iso
Use the ISO to start the RHCOS installation. Use one of the following installation options:
- Burn the ISO image to a disk and boot it directly.
- Use ISO redirection by using a lights-out management (LOM) interface.
Boot the RHCOS ISO image without specifying any options or interrupting the live boot sequence. Wait for the installer to boot into a shell prompt in the RHCOS live environment.
NoteIt is possible to interrupt the RHCOS installation boot process to add kernel arguments. However, for this ISO procedure you should use the
coreos-installer
command as outlined in the following steps, instead of adding kernel arguments.Run the
coreos-installer
command and specify the options that meet your installation requirements. At a minimum, you must specify the URL that points to the Ignition config file for the node type, and the device that you are installing to:$ sudo coreos-installer install --ignition-url=http://<HTTP_server>/<node_type>.ign <device> --ignition-hash=sha512-<digest> 12
- 1 1
- You must run the
coreos-installer
command by usingsudo
, because thecore
user does not have the required root privileges to perform the installation. - 2
- The
--ignition-hash
option is required when the Ignition config file is obtained through an HTTP URL to validate the authenticity of the Ignition config file on the cluster node.<digest>
is the Ignition config file SHA512 digest obtained in a preceding step.
NoteIf you want to provide your Ignition config files through an HTTPS server that uses TLS, you can add the internal certificate authority (CA) to the system trust store before running
coreos-installer
.The following example initializes a bootstrap node installation to the
/dev/sda
device. The Ignition config file for the bootstrap node is obtained from an HTTP web server with the IP address 192.168.1.2:$ sudo coreos-installer install --ignition-url=http://192.168.1.2:80/installation_directory/bootstrap.ign /dev/sda --ignition-hash=sha512-a5a2d43879223273c9b60af66b44202a1d1248fc01cf156c46d4a79f552b6bad47bc8cc78ddf0116e80c59d2ea9e32ba53bc807afbca581aa059311def2c3e3b
Monitor the progress of the RHCOS installation on the console of the machine.
ImportantBe sure that the installation is successful on each node before commencing with the OpenShift Container Platform installation. Observing the installation process can also help to determine the cause of RHCOS installation issues that might arise.
- After RHCOS installs, you must reboot the system. During the system reboot, it applies the Ignition config file that you specified.
Check the console output to verify that Ignition ran.
Example command
Ignition: ran on 2022/03/14 14:48:33 UTC (this boot) Ignition: user-provided config was applied
Continue to create the other machines for your cluster.
ImportantYou must create the bootstrap and control plane machines at this time. If the control plane machines are not made schedulable, also create at least two compute machines before you install OpenShift Container Platform.
If the required network, DNS, and load balancer infrastructure are in place, the OpenShift Container Platform bootstrap process begins automatically after the RHCOS nodes have rebooted.
NoteRHCOS nodes do not include a default password for the
core
user. You can access the nodes by runningssh core@<node>.<cluster_name>.<base_domain>
as a user with access to the SSH private key that is paired to the public key that you specified in yourinstall_config.yaml
file. OpenShift Container Platform 4 cluster nodes running RHCOS are immutable and rely on Operators to apply cluster changes. Accessing cluster nodes by using SSH is not recommended. However, when investigating installation issues, if the OpenShift Container Platform API is not available, or the kubelet is not properly functioning on a target node, SSH access might be required for debugging or disaster recovery.
4.11.2. Installing RHCOS by using PXE or iPXE booting
You can use PXE or iPXE booting to install RHCOS on the machines.
Prerequisites
- You have created the Ignition config files for your cluster.
- You have configured suitable network, DNS and load balancing infrastructure.
- You have configured suitable PXE or iPXE infrastructure.
- You have an HTTP server that can be accessed from your computer, and from the machines that you create.
- You have reviewed the Advanced RHCOS installation configuration section for different ways to configure features, such as networking and disk partitioning.
Procedure
Upload the bootstrap, control plane, and compute node Ignition config files that the installation program created to your HTTP server. Note the URLs of these files.
ImportantYou can add or change configuration settings in your Ignition configs before saving them to your HTTP server. If you plan to add more compute machines to your cluster after you finish installation, do not delete these files.
From the installation host, validate that the Ignition config files are available on the URLs. The following example gets the Ignition config file for the bootstrap node:
$ curl -k http://<HTTP_server>/bootstrap.ign 1
Example output
% Total % Received % Xferd Average Speed Time Time Time Current Dload Upload Total Spent Left Speed 0 0 0 0 0 0 0 0 --:--:-- --:--:-- --:--:-- 0{"ignition":{"version":"3.2.0"},"passwd":{"users":[{"name":"core","sshAuthorizedKeys":["ssh-rsa...
Replace
bootstrap.ign
withmaster.ign
orworker.ign
in the command to validate that the Ignition config files for the control plane and compute nodes are also available.Although it is possible to obtain the RHCOS
kernel
,initramfs
androotfs
files that are required for your preferred method of installing operating system instances from the RHCOS image mirror page, the recommended way to obtain the correct version of your RHCOS files are from the output ofopenshift-install
command:$ openshift-install coreos print-stream-json | grep -Eo '"https.*(kernel-|initramfs.|rootfs.)\w+(\.img)?"'
Example output
"<url>/art/storage/releases/rhcos-4.13-aarch64/<release>/aarch64/rhcos-<release>-live-kernel-aarch64" "<url>/art/storage/releases/rhcos-4.13-aarch64/<release>/aarch64/rhcos-<release>-live-initramfs.aarch64.img" "<url>/art/storage/releases/rhcos-4.13-aarch64/<release>/aarch64/rhcos-<release>-live-rootfs.aarch64.img" "<url>/art/storage/releases/rhcos-4.13-ppc64le/49.84.202110081256-0/ppc64le/rhcos-<release>-live-kernel-ppc64le" "<url>/art/storage/releases/rhcos-4.13-ppc64le/<release>/ppc64le/rhcos-<release>-live-initramfs.ppc64le.img" "<url>/art/storage/releases/rhcos-4.13-ppc64le/<release>/ppc64le/rhcos-<release>-live-rootfs.ppc64le.img" "<url>/art/storage/releases/rhcos-4.13-s390x/<release>/s390x/rhcos-<release>-live-kernel-s390x" "<url>/art/storage/releases/rhcos-4.13-s390x/<release>/s390x/rhcos-<release>-live-initramfs.s390x.img" "<url>/art/storage/releases/rhcos-4.13-s390x/<release>/s390x/rhcos-<release>-live-rootfs.s390x.img" "<url>/art/storage/releases/rhcos-4.13/<release>/x86_64/rhcos-<release>-live-kernel-x86_64" "<url>/art/storage/releases/rhcos-4.13/<release>/x86_64/rhcos-<release>-live-initramfs.x86_64.img" "<url>/art/storage/releases/rhcos-4.13/<release>/x86_64/rhcos-<release>-live-rootfs.x86_64.img"
ImportantThe RHCOS artifacts might not change with every release of OpenShift Container Platform. You must download images with the highest version that is less than or equal to the OpenShift Container Platform version that you install. Only use the appropriate
kernel
,initramfs
, androotfs
artifacts described below for this procedure. RHCOS QCOW2 images are not supported for this installation type.The file names contain the OpenShift Container Platform version number. They resemble the following examples:
-
kernel
:rhcos-<version>-live-kernel-<architecture>
-
initramfs
:rhcos-<version>-live-initramfs.<architecture>.img
-
rootfs
:rhcos-<version>-live-rootfs.<architecture>.img
-
Upload the
rootfs
,kernel
, andinitramfs
files to your HTTP server.ImportantIf you plan to add more compute machines to your cluster after you finish installation, do not delete these files.
- Configure the network boot infrastructure so that the machines boot from their local disks after RHCOS is installed on them.
Configure PXE or iPXE installation for the RHCOS images and begin the installation.
Modify one of the following example menu entries for your environment and verify that the image and Ignition files are properly accessible:
For PXE (
x86_64
):DEFAULT pxeboot TIMEOUT 20 PROMPT 0 LABEL pxeboot KERNEL http://<HTTP_server>/rhcos-<version>-live-kernel-<architecture> 1 APPEND initrd=http://<HTTP_server>/rhcos-<version>-live-initramfs.<architecture>.img coreos.live.rootfs_url=http://<HTTP_server>/rhcos-<version>-live-rootfs.<architecture>.img coreos.inst.install_dev=/dev/sda coreos.inst.ignition_url=http://<HTTP_server>/bootstrap.ign 2 3
- 1 1
- Specify the location of the live
kernel
file that you uploaded to your HTTP server. The URL must be HTTP, TFTP, or FTP; HTTPS and NFS are not supported. - 2
- If you use multiple NICs, specify a single interface in the
ip
option. For example, to use DHCP on a NIC that is namedeno1
, setip=eno1:dhcp
. - 3
- Specify the locations of the RHCOS files that you uploaded to your HTTP server. The
initrd
parameter value is the location of theinitramfs
file, thecoreos.live.rootfs_url
parameter value is the location of therootfs
file, and thecoreos.inst.ignition_url
parameter value is the location of the bootstrap Ignition config file. You can also add more kernel arguments to theAPPEND
line to configure networking or other boot options.
NoteThis configuration does not enable serial console access on machines with a graphical console. To configure a different console, add one or more
console=
arguments to theAPPEND
line. For example, addconsole=tty0 console=ttyS0
to set the first PC serial port as the primary console and the graphical console as a secondary console. For more information, see How does one set up a serial terminal and/or console in Red Hat Enterprise Linux? and "Enabling the serial console for PXE and ISO installation" in the "Advanced RHCOS installation configuration" section.For iPXE (
x86_64
+aarch64
):kernel http://<HTTP_server>/rhcos-<version>-live-kernel-<architecture> initrd=main coreos.live.rootfs_url=http://<HTTP_server>/rhcos-<version>-live-rootfs.<architecture>.img coreos.inst.install_dev=/dev/sda coreos.inst.ignition_url=http://<HTTP_server>/bootstrap.ign 1 2 initrd --name main http://<HTTP_server>/rhcos-<version>-live-initramfs.<architecture>.img 3 boot
- 1
- Specify the locations of the RHCOS files that you uploaded to your HTTP server. The
kernel
parameter value is the location of thekernel
file, theinitrd=main
argument is needed for booting on UEFI systems, thecoreos.live.rootfs_url
parameter value is the location of therootfs
file, and thecoreos.inst.ignition_url
parameter value is the location of the bootstrap Ignition config file. - 2
- If you use multiple NICs, specify a single interface in the
ip
option. For example, to use DHCP on a NIC that is namedeno1
, setip=eno1:dhcp
. - 3
- Specify the location of the
initramfs
file that you uploaded to your HTTP server.
NoteThis configuration does not enable serial console access on machines with a graphical console. To configure a different console, add one or more
console=
arguments to thekernel
line. For example, addconsole=tty0 console=ttyS0
to set the first PC serial port as the primary console and the graphical console as a secondary console. For more information, see How does one set up a serial terminal and/or console in Red Hat Enterprise Linux? and "Enabling the serial console for PXE and ISO installation" in the "Advanced RHCOS installation configuration" section.NoteTo network boot the CoreOS
kernel
onaarch64
architecture, you need to use a version of iPXE build with theIMAGE_GZIP
option enabled. SeeIMAGE_GZIP
option in iPXE.For PXE (with UEFI and Grub as second stage) on
aarch64
:menuentry 'Install CoreOS' { linux rhcos-<version>-live-kernel-<architecture> coreos.live.rootfs_url=http://<HTTP_server>/rhcos-<version>-live-rootfs.<architecture>.img coreos.inst.install_dev=/dev/sda coreos.inst.ignition_url=http://<HTTP_server>/bootstrap.ign 1 2 initrd rhcos-<version>-live-initramfs.<architecture>.img 3 }
- 1
- Specify the locations of the RHCOS files that you uploaded to your HTTP/TFTP server. The
kernel
parameter value is the location of thekernel
file on your TFTP server. Thecoreos.live.rootfs_url
parameter value is the location of therootfs
file, and thecoreos.inst.ignition_url
parameter value is the location of the bootstrap Ignition config file on your HTTP Server. - 2
- If you use multiple NICs, specify a single interface in the
ip
option. For example, to use DHCP on a NIC that is namedeno1
, setip=eno1:dhcp
. - 3
- Specify the location of the
initramfs
file that you uploaded to your TFTP server.
Monitor the progress of the RHCOS installation on the console of the machine.
ImportantBe sure that the installation is successful on each node before commencing with the OpenShift Container Platform installation. Observing the installation process can also help to determine the cause of RHCOS installation issues that might arise.
- After RHCOS installs, the system reboots. During reboot, the system applies the Ignition config file that you specified.
Check the console output to verify that Ignition ran.
Example command
Ignition: ran on 2022/03/14 14:48:33 UTC (this boot) Ignition: user-provided config was applied
Continue to create the machines for your cluster.
ImportantYou must create the bootstrap and control plane machines at this time. If the control plane machines are not made schedulable, also create at least two compute machines before you install the cluster.
If the required network, DNS, and load balancer infrastructure are in place, the OpenShift Container Platform bootstrap process begins automatically after the RHCOS nodes have rebooted.
NoteRHCOS nodes do not include a default password for the
core
user. You can access the nodes by runningssh core@<node>.<cluster_name>.<base_domain>
as a user with access to the SSH private key that is paired to the public key that you specified in yourinstall_config.yaml
file. OpenShift Container Platform 4 cluster nodes running RHCOS are immutable and rely on Operators to apply cluster changes. Accessing cluster nodes by using SSH is not recommended. However, when investigating installation issues, if the OpenShift Container Platform API is not available, or the kubelet is not properly functioning on a target node, SSH access might be required for debugging or disaster recovery.
4.11.3. Advanced RHCOS installation configuration
A key benefit for manually provisioning the Red Hat Enterprise Linux CoreOS (RHCOS) nodes for OpenShift Container Platform is to be able to do configuration that is not available through default OpenShift Container Platform installation methods. This section describes some of the configurations that you can do using techniques that include:
- Passing kernel arguments to the live installer
-
Running
coreos-installer
manually from the live system - Customizing a live ISO or PXE boot image
The advanced configuration topics for manual Red Hat Enterprise Linux CoreOS (RHCOS) installations detailed in this section relate to disk partitioning, networking, and using Ignition configs in different ways.
4.11.3.1. Using advanced networking options for PXE and ISO installations
Networking for OpenShift Container Platform nodes uses DHCP by default to gather all necessary configuration settings. To set up static IP addresses or configure special settings, such as bonding, you can do one of the following:
- Pass special kernel parameters when you boot the live installer.
- Use a machine config to copy networking files to the installed system.
- Configure networking from a live installer shell prompt, then copy those settings to the installed system so that they take effect when the installed system first boots.
To configure a PXE or iPXE installation, use one of the following options:
- See the "Advanced RHCOS installation reference" tables.
- Use a machine config to copy networking files to the installed system.
To configure an ISO installation, use the following procedure.
Procedure
- Boot the ISO installer.
-
From the live system shell prompt, configure networking for the live system using available RHEL tools, such as
nmcli
ornmtui
. Run the
coreos-installer
command to install the system, adding the--copy-network
option to copy networking configuration. For example:$ sudo coreos-installer install --copy-network \ --ignition-url=http://host/worker.ign /dev/disk/by-id/scsi-<serial_number>
ImportantThe
--copy-network
option only copies networking configuration found under/etc/NetworkManager/system-connections
. In particular, it does not copy the system hostname.- Reboot into the installed system.
Additional resources
-
See Getting started with nmcli and Getting started with nmtui in the RHEL 8 documentation for more information about the
nmcli
andnmtui
tools.
4.11.3.2. Disk partitioning
Disk partitions are created on OpenShift Container Platform cluster nodes during the Red Hat Enterprise Linux CoreOS (RHCOS) installation. Each RHCOS node of a particular architecture uses the same partition layout, unless you override the default partitioning configuration. During the RHCOS installation, the size of the root file system is increased to use any remaining available space on the target device.
The use of a custom partition scheme on your node might result in OpenShift Container Platform not monitoring or alerting on some node partitions. If you override the default partitioning, see Understanding OpenShift File System Monitoring (eviction conditions) for more information about how OpenShift Container Platform monitors your host file systems.
OpenShift Container Platform monitors the following two filesystem identifiers:
-
nodefs
, which is the filesystem that contains/var/lib/kubelet
-
imagefs
, which is the filesystem that contains/var/lib/containers
For the default partition scheme, nodefs
and imagefs
monitor the same root filesystem, /
.
To override the default partitioning when installing RHCOS on an OpenShift Container Platform cluster node, you must create separate partitions.
For disk sizes larger than 100GB, and especially disk sizes larger than 1TB, create a separate /var
partition. See "Creating a separate /var
partition" and this Red Hat Knowledgebase article for more information.
Consider a situation where you want to add a separate storage partition for your containers and container images. For example, by mounting /var/lib/containers
in a separate partition, the kubelet separately monitors /var/lib/containers
as the imagefs
directory and the root file system as the nodefs
directory.
If you have resized your disk size to host a larger file system, consider creating a separate /var/lib/containers
partition. Consider resizing a disk that has an xfs
format to reduce CPU time issues caused by a high number of allocation groups.
4.11.3.2.1. Creating a separate /var
partition
In general, you should use the default disk partitioning that is created during the RHCOS installation. However, there are cases where you might want to create a separate partition for a directory that you expect to grow.
OpenShift Container Platform supports the addition of a single partition to attach storage to either the /var
directory or a subdirectory of /var
. For example:
-
/var/lib/containers
: Holds container-related content that can grow as more images and containers are added to a system. -
/var/lib/etcd
: Holds data that you might want to keep separate for purposes such as performance optimization of etcd storage. /var
: Holds data that you might want to keep separate for purposes such as auditing.ImportantFor disk sizes larger than 100GB, and especially larger than 1TB, create a separate
/var
partition.
Storing the contents of a /var
directory separately makes it easier to grow storage for those areas as needed and reinstall OpenShift Container Platform at a later date and keep that data intact. With this method, you will not have to pull all your containers again, nor will you have to copy massive log files when you update systems.
The use of a separate partition for the /var
directory or a subdirectory of /var
also prevents data growth in the partitioned directory from filling up the root file system.
The following procedure sets up a separate /var
partition by adding a machine config manifest that is wrapped into the Ignition config file for a node type during the preparation phase of an installation.
Procedure
On your installation host, change to the directory that contains the OpenShift Container Platform installation program and generate the Kubernetes manifests for the cluster:
$ openshift-install create manifests --dir <installation_directory>
Create a Butane config that configures the additional partition. For example, name the file
$HOME/clusterconfig/98-var-partition.bu
, change the disk device name to the name of the storage device on theworker
systems, and set the storage size as appropriate. This example places the/var
directory on a separate partition:variant: openshift version: 4.13.0 metadata: labels: machineconfiguration.openshift.io/role: worker name: 98-var-partition storage: disks: - device: /dev/disk/by-id/<device_name> 1 partitions: - label: var start_mib: <partition_start_offset> 2 size_mib: <partition_size> 3 number: 5 filesystems: - device: /dev/disk/by-partlabel/var path: /var format: xfs mount_options: [defaults, prjquota] 4 with_mount_unit: true
- 1
- The storage device name of the disk that you want to partition.
- 2
- When adding a data partition to the boot disk, a minimum offset value of 25000 mebibytes is recommended. The root file system is automatically resized to fill all available space up to the specified offset. If no offset value is specified, or if the specified value is smaller than the recommended minimum, the resulting root file system will be too small, and future reinstalls of RHCOS might overwrite the beginning of the data partition.
- 3
- The size of the data partition in mebibytes.
- 4
- The
prjquota
mount option must be enabled for filesystems used for container storage.
NoteWhen creating a separate
/var
partition, you cannot use different instance types for compute nodes, if the different instance types do not have the same device name.Create a manifest from the Butane config and save it to the
clusterconfig/openshift
directory. For example, run the following command:$ butane $HOME/clusterconfig/98-var-partition.bu -o $HOME/clusterconfig/openshift/98-var-partition.yaml
Create the Ignition config files:
$ openshift-install create ignition-configs --dir <installation_directory> 1
- 1
- For
<installation_directory>
, specify the same installation directory.
Ignition config files are created for the bootstrap, control plane, and compute nodes in the installation directory:
. ├── auth │ ├── kubeadmin-password │ └── kubeconfig ├── bootstrap.ign ├── master.ign ├── metadata.json └── worker.ign
The files in the
<installation_directory>/manifest
and<installation_directory>/openshift
directories are wrapped into the Ignition config files, including the file that contains the98-var-partition
customMachineConfig
object.
Next steps
- You can apply the custom disk partitioning by referencing the Ignition config files during the RHCOS installations.
4.11.3.2.2. Retaining existing partitions
For an ISO installation, you can add options to the coreos-installer
command that cause the installer to maintain one or more existing partitions. For a PXE installation, you can add coreos.inst.*
options to the APPEND
parameter to preserve partitions.
Saved partitions might be data partitions from an existing OpenShift Container Platform system. You can identify the disk partitions you want to keep either by partition label or by number.
If you save existing partitions, and those partitions do not leave enough space for RHCOS, the installation will fail without damaging the saved partitions.
Retaining existing partitions during an ISO installation
This example preserves any partition in which the partition label begins with data
(data*
):
# coreos-installer install --ignition-url http://10.0.2.2:8080/user.ign \ --save-partlabel 'data*' /dev/disk/by-id/scsi-<serial_number>
The following example illustrates running the coreos-installer
in a way that preserves the sixth (6) partition on the disk:
# coreos-installer install --ignition-url http://10.0.2.2:8080/user.ign \ --save-partindex 6 /dev/disk/by-id/scsi-<serial_number>
This example preserves partitions 5 and higher:
# coreos-installer install --ignition-url http://10.0.2.2:8080/user.ign --save-partindex 5- /dev/disk/by-id/scsi-<serial_number>
In the previous examples where partition saving is used, coreos-installer
recreates the partition immediately.
Retaining existing partitions during a PXE installation
This APPEND
option preserves any partition in which the partition label begins with 'data' ('data*'):
coreos.inst.save_partlabel=data*
This APPEND
option preserves partitions 5 and higher:
coreos.inst.save_partindex=5-
This APPEND
option preserves partition 6:
coreos.inst.save_partindex=6
4.11.3.3. Identifying Ignition configs
When doing an RHCOS manual installation, there are two types of Ignition configs that you can provide, with different reasons for providing each one:
Permanent install Ignition config: Every manual RHCOS installation needs to pass one of the Ignition config files generated by
openshift-installer
, such asbootstrap.ign
,master.ign
andworker.ign
, to carry out the installation.ImportantIt is not recommended to modify these Ignition config files directly. You can update the manifest files that are wrapped into the Ignition config files, as outlined in examples in the preceding sections.
For PXE installations, you pass the Ignition configs on the
APPEND
line using thecoreos.inst.ignition_url=
option. For ISO installations, after the ISO boots to the shell prompt, you identify the Ignition config on thecoreos-installer
command line with the--ignition-url=
option. In both cases, only HTTP and HTTPS protocols are supported.Live install Ignition config: This type can be created by using the
coreos-installer
customize
subcommand and its various options. With this method, the Ignition config passes to the live install medium, runs immediately upon booting, and performs setup tasks before or after the RHCOS system installs to disk. This method should only be used for performing tasks that must be done once and not applied again later, such as with advanced partitioning that cannot be done using a machine config.For PXE or ISO boots, you can create the Ignition config and
APPEND
theignition.config.url=
option to identify the location of the Ignition config. You also need to appendignition.firstboot ignition.platform.id=metal
or theignition.config.url
option will be ignored.
4.11.3.4. Default console configuration
Red Hat Enterprise Linux CoreOS (RHCOS) nodes installed from an OpenShift Container Platform 4.13 boot image use a default console that is meant to accomodate most virtualized and bare metal setups. Different cloud and virtualization platforms may use different default settings depending on the chosen architecture. Bare metal installations use the kernel default settings which typically means the graphical console is the primary console and the serial console is disabled.
The default consoles may not match your specific hardware configuration or you might have specific needs that require you to adjust the default console. For example:
- You want to access the emergency shell on the console for debugging purposes.
- Your cloud platform does not provide interactive access to the graphical console, but provides a serial console.
- You want to enable multiple consoles.
Console configuration is inherited from the boot image. This means that new nodes in existing clusters are unaffected by changes to the default console.
You can configure the console for bare metal installations in the following ways:
-
Using
coreos-installer
manually on the command line. -
Using the
coreos-installer iso customize
orcoreos-installer pxe customize
subcommands with the--dest-console
option to create a custom image that automates the process.
For advanced customization, perform console configuration using the coreos-installer iso
or coreos-installer pxe
subcommands, and not kernel arguments.
4.11.3.5. Enabling the serial console for PXE and ISO installations
By default, the Red Hat Enterprise Linux CoreOS (RHCOS) serial console is disabled and all output is written to the graphical console. You can enable the serial console for an ISO installation and reconfigure the bootloader so that output is sent to both the serial console and the graphical console.
Procedure
- Boot the ISO installer.
Run the
coreos-installer
command to install the system, adding the--console
option once to specify the graphical console, and a second time to specify the serial console:$ coreos-installer install \ --console=tty0 \1 --console=ttyS0,<options> \2 --ignition-url=http://host/worker.ign /dev/disk/by-id/scsi-<serial_number>
- 1
- The desired secondary console. In this case, the graphical console. Omitting this option will disable the graphical console.
- 2
- The desired primary console. In this case the serial console. The
options
field defines the baud rate and other settings. A common value for this field is11520n8
. If no options are provided, the default kernel value of9600n8
is used. For more information on the format of this option, see Linux kernel serial console documentation.
Reboot into the installed system.
NoteA similar outcome can be obtained by using the
coreos-installer install --append-karg
option, and specifying the console withconsole=
. However, this will only set the console for the kernel and not the bootloader.
To configure a PXE installation, make sure the coreos.inst.install_dev
kernel command line option is omitted, and use the shell prompt to run coreos-installer
manually using the above ISO installation procedure.
4.11.3.6. Customizing a live RHCOS ISO or PXE install
You can use the live ISO image or PXE environment to install RHCOS by injecting an Ignition config file directly into the image. This creates a customized image that you can use to provision your system.
For an ISO image, the mechanism to do this is the coreos-installer iso customize
subcommand, which modifies the .iso
file with your configuration. Similarly, the mechanism for a PXE environment is the coreos-installer pxe customize
subcommand, which creates a new initramfs
file that includes your customizations.
The customize
subcommand is a general purpose tool that can embed other types of customizations as well. The following tasks are examples of some of the more common customizations:
- Inject custom CA certificates for when corporate security policy requires their use.
- Configure network settings without the need for kernel arguments.
- Embed arbitrary preinstall and post-install scripts or binaries.
4.11.3.7. Customizing a live RHCOS ISO image
You can customize a live RHCOS ISO image directly with the coreos-installer iso customize
subcommand. When you boot the ISO image, the customizations are applied automatically.
You can use this feature to configure the ISO image to automatically install RHCOS.
Procedure
-
Download the
coreos-installer
binary from thecoreos-installer
image mirror page. Retrieve the RHCOS ISO image from the RHCOS image mirror page and the Ignition config file, and then run the following command to inject the Ignition config directly into the ISO image:
$ coreos-installer iso customize rhcos-<version>-live.x86_64.iso \ --dest-ignition bootstrap.ign \ 1 --dest-device /dev/disk/by-id/scsi-<serial_number> 2
- 1
- The Ignition config file that is generated from the
openshift-installer
installation program. - 2
- When you specify this option, the ISO image automatically runs an installation. Otherwise, the image remains configured for installation, but does not install automatically unless you specify the
coreos.inst.install_dev
kernel argument.
Optional: To remove the ISO image customizations and return the image to its pristine state, run:
$ coreos-installer iso reset rhcos-<version>-live.x86_64.iso
You can now re-customize the live ISO image or use it in its pristine state.
Applying your customizations affects every subsequent boot of RHCOS.
4.11.3.7.1. Modifying a live install ISO image to enable the serial console
On clusters installed with OpenShift Container Platform 4.12 and above, the serial console is disabled by default and all output is written to the graphical console. You can enable the serial console with the following procedure.
Procedure
-
Download the
coreos-installer
binary from thecoreos-installer
image mirror page. Retrieve the RHCOS ISO image from the RHCOS image mirror page and run the following command to customize the ISO image to enable the serial console to receive output:
$ coreos-installer iso customize rhcos-<version>-live.x86_64.iso \ --dest-ignition <path> \1 --dest-console tty0 \2 --dest-console ttyS0,<options> \3 --dest-device /dev/disk/by-id/scsi-<serial_number> 4
- 1
- The location of the Ignition config to install.
- 2
- The desired secondary console. In this case, the graphical console. Omitting this option will disable the graphical console.
- 3
- The desired primary console. In this case, the serial console. The
options
field defines the baud rate and other settings. A common value for this field is115200n8
. If no options are provided, the default kernel value of9600n8
is used. For more information on the format of this option, see the Linux kernel serial console documentation. - 4
- The specified disk to install to. If you omit this option, the ISO image automatically runs the installation program which will fail unless you also specify the
coreos.inst.install_dev
kernel argument.
NoteThe
--dest-console
option affects the installed system and not the live ISO system. To modify the console for a live ISO system, use the--live-karg-append
option and specify the console withconsole=
.Your customizations are applied and affect every subsequent boot of the ISO image.
Optional: To remove the ISO image customizations and return the image to its original state, run the following command:
$ coreos-installer iso reset rhcos-<version>-live.x86_64.iso
You can now recustomize the live ISO image or use it in its original state.
4.11.3.7.2. Modifying a live install ISO image to use a custom certificate authority
You can provide certificate authority (CA) certificates to Ignition with the --ignition-ca
flag of the customize
subcommand. You can use the CA certificates during both the installation boot and when provisioning the installed system.
Custom CA certificates affect how Ignition fetches remote resources but they do not affect the certificates installed onto the system.
Procedure
-
Download the
coreos-installer
binary from thecoreos-installer
image mirror page. Retrieve the RHCOS ISO image from the RHCOS image mirror page and run the following command to customize the ISO image for use with a custom CA:
$ coreos-installer iso customize rhcos-<version>-live.x86_64.iso --ignition-ca cert.pem
The coreos.inst.ignition_url
kernel parameter does not work with the --ignition-ca
flag. You must use the --dest-ignition
flag to create a customized image for each cluster.
Applying your custom CA certificate affects every subsequent boot of RHCOS.
4.11.3.7.3. Modifying a live install ISO image with customized network settings
You can embed a NetworkManager keyfile into the live ISO image and pass it through to the installed system with the --network-keyfile
flag of the customize
subcommand.
When creating a connection profile, you must use a .nmconnection
filename extension in the filename of the connection profile. If you do not use a .nmconnection
filename extension, the cluster will apply the connection profile to the live environment, but it will not apply the configuration when the cluster first boots up the nodes, resulting in a setup that does not work.
Procedure
-
Download the
coreos-installer
binary from thecoreos-installer
image mirror page. Create a connection profile for a bonded interface. For example, create the
bond0.nmconnection
file in your local directory with the following content:[connection] id=bond0 type=bond interface-name=bond0 multi-connect=1 [bond] miimon=100 mode=active-backup [ipv4] method=auto [ipv6] method=auto
Create a connection profile for a secondary interface to add to the bond. For example, create the
bond0-proxy-em1.nmconnection
file in your local directory with the following content:[connection] id=em1 type=ethernet interface-name=em1 master=bond0 multi-connect=1 slave-type=bond
Create a connection profile for a secondary interface to add to the bond. For example, create the
bond0-proxy-em2.nmconnection
file in your local directory with the following content:[connection] id=em2 type=ethernet interface-name=em2 master=bond0 multi-connect=1 slave-type=bond
Retrieve the RHCOS ISO image from the RHCOS image mirror page and run the following command to customize the ISO image with your configured networking:
$ coreos-installer iso customize rhcos-<version>-live.x86_64.iso \ --network-keyfile bond0.nmconnection \ --network-keyfile bond0-proxy-em1.nmconnection \ --network-keyfile bond0-proxy-em2.nmconnection
Network settings are applied to the live system and are carried over to the destination system.
4.11.3.8. Customizing a live RHCOS PXE environment
You can customize a live RHCOS PXE environment directly with the coreos-installer pxe customize
subcommand. When you boot the PXE environment, the customizations are applied automatically.
You can use this feature to configure the PXE environment to automatically install RHCOS.
Procedure
-
Download the
coreos-installer
binary from thecoreos-installer
image mirror page. Retrieve the RHCOS
kernel
,initramfs
androotfs
files from the RHCOS image mirror page and the Ignition config file, and then run the following command to create a newinitramfs
file that contains the customizations from your Ignition config:$ coreos-installer pxe customize rhcos-<version>-live-initramfs.x86_64.img \ --dest-ignition bootstrap.ign \ 1 --dest-device /dev/disk/by-id/scsi-<serial_number> \ 2 -o rhcos-<version>-custom-initramfs.x86_64.img 3
- 1
- The Ignition config file that is generated from
openshift-installer
. - 2
- When you specify this option, the PXE environment automatically runs an install. Otherwise, the image remains configured for installing, but does not do so automatically unless you specify the
coreos.inst.install_dev
kernel argument. - 3
- Use the customized
initramfs
file in your PXE configuration. Add theignition.firstboot
andignition.platform.id=metal
kernel arguments if they are not already present.
Applying your customizations affects every subsequent boot of RHCOS.
4.11.3.8.1. Modifying a live install PXE environment to enable the serial console
On clusters installed with OpenShift Container Platform 4.12 and above, the serial console is disabled by default and all output is written to the graphical console. You can enable the serial console with the following procedure.
Procedure
-
Download the
coreos-installer
binary from thecoreos-installer
image mirror page. Retrieve the RHCOS
kernel
,initramfs
androotfs
files from the RHCOS image mirror page and the Ignition config file, and then run the following command to create a new customizedinitramfs
file that enables the serial console to receive output:$ coreos-installer pxe customize rhcos-<version>-live-initramfs.x86_64.img \ --dest-ignition <path> \1 --dest-console tty0 \2 --dest-console ttyS0,<options> \3 --dest-device /dev/disk/by-id/scsi-<serial_number> \4 -o rhcos-<version>-custom-initramfs.x86_64.img 5
- 1
- The location of the Ignition config to install.
- 2
- The desired secondary console. In this case, the graphical console. Omitting this option will disable the graphical console.
- 3
- The desired primary console. In this case, the serial console. The
options
field defines the baud rate and other settings. A common value for this field is115200n8
. If no options are provided, the default kernel value of9600n8
is used. For more information on the format of this option, see the Linux kernel serial console documentation. - 4
- The specified disk to install to. If you omit this option, the PXE environment automatically runs the installer which will fail unless you also specify the
coreos.inst.install_dev
kernel argument. - 5
- Use the customized
initramfs
file in your PXE configuration. Add theignition.firstboot
andignition.platform.id=metal
kernel arguments if they are not already present.
Your customizations are applied and affect every subsequent boot of the PXE environment.
4.11.3.8.2. Modifying a live install PXE environment to use a custom certificate authority
You can provide certificate authority (CA) certificates to Ignition with the --ignition-ca
flag of the customize
subcommand. You can use the CA certificates during both the installation boot and when provisioning the installed system.
Custom CA certificates affect how Ignition fetches remote resources but they do not affect the certificates installed onto the system.
Procedure
-
Download the
coreos-installer
binary from thecoreos-installer
image mirror page. Retrieve the RHCOS
kernel
,initramfs
androotfs
files from the RHCOS image mirror page and run the following command to create a new customizedinitramfs
file for use with a custom CA:$ coreos-installer pxe customize rhcos-<version>-live-initramfs.x86_64.img \ --ignition-ca cert.pem \ -o rhcos-<version>-custom-initramfs.x86_64.img
-
Use the customized
initramfs
file in your PXE configuration. Add theignition.firstboot
andignition.platform.id=metal
kernel arguments if they are not already present.
The coreos.inst.ignition_url
kernel parameter does not work with the --ignition-ca
flag. You must use the --dest-ignition
flag to create a customized image for each cluster.
Applying your custom CA certificate affects every subsequent boot of RHCOS.
4.11.3.8.3. Modifying a live install PXE environment with customized network settings
You can embed a NetworkManager keyfile into the live PXE environment and pass it through to the installed system with the --network-keyfile
flag of the customize
subcommand.
When creating a connection profile, you must use a .nmconnection
filename extension in the filename of the connection profile. If you do not use a .nmconnection
filename extension, the cluster will apply the connection profile to the live environment, but it will not apply the configuration when the cluster first boots up the nodes, resulting in a setup that does not work.
Procedure
-
Download the
coreos-installer
binary from thecoreos-installer
image mirror page. Create a connection profile for a bonded interface. For example, create the
bond0.nmconnection
file in your local directory with the following content:[connection] id=bond0 type=bond interface-name=bond0 multi-connect=1 [bond] miimon=100 mode=active-backup [ipv4] method=auto [ipv6] method=auto
Create a connection profile for a secondary interface to add to the bond. For example, create the
bond0-proxy-em1.nmconnection
file in your local directory with the following content:[connection] id=em1 type=ethernet interface-name=em1 master=bond0 multi-connect=1 slave-type=bond
Create a connection profile for a secondary interface to add to the bond. For example, create the
bond0-proxy-em2.nmconnection
file in your local directory with the following content:[connection] id=em2 type=ethernet interface-name=em2 master=bond0 multi-connect=1 slave-type=bond
Retrieve the RHCOS
kernel
,initramfs
androotfs
files from the RHCOS image mirror page and run the following command to create a new customizedinitramfs
file that contains your configured networking:$ coreos-installer pxe customize rhcos-<version>-live-initramfs.x86_64.img \ --network-keyfile bond0.nmconnection \ --network-keyfile bond0-proxy-em1.nmconnection \ --network-keyfile bond0-proxy-em2.nmconnection \ -o rhcos-<version>-custom-initramfs.x86_64.img
Use the customized
initramfs
file in your PXE configuration. Add theignition.firstboot
andignition.platform.id=metal
kernel arguments if they are not already present.Network settings are applied to the live system and are carried over to the destination system.
4.11.3.9. Advanced RHCOS installation reference
This section illustrates the networking configuration and other advanced options that allow you to modify the Red Hat Enterprise Linux CoreOS (RHCOS) manual installation process. The following tables describe the kernel arguments and command-line options you can use with the RHCOS live installer and the coreos-installer
command.
4.11.3.9.1. Networking and bonding options for ISO installations
If you install RHCOS from an ISO image, you can add kernel arguments manually when you boot the image to configure networking for a node. If no networking arguments are specified, DHCP is activated in the initramfs when RHCOS detects that networking is required to fetch the Ignition config file.
When adding networking arguments manually, you must also add the rd.neednet=1
kernel argument to bring the network up in the initramfs.
The following information provides examples for configuring networking and bonding on your RHCOS nodes for ISO installations. The examples describe how to use the ip=
, nameserver=
, and bond=
kernel arguments.
Ordering is important when adding the kernel arguments: ip=
, nameserver=
, and then bond=
.
The networking options are passed to the dracut
tool during system boot. For more information about the networking options supported by dracut
, see the dracut.cmdline
manual page.
The following examples are the networking options for ISO installation.
Configuring DHCP or static IP addresses
To configure an IP address, either use DHCP (ip=dhcp
) or set an individual static IP address (ip=<host_ip>
). If setting a static IP, you must then identify the DNS server IP address (nameserver=<dns_ip>
) on each node. The following example sets:
-
The node’s IP address to
10.10.10.2
-
The gateway address to
10.10.10.254
-
The netmask to
255.255.255.0
-
The hostname to
core0.example.com
-
The DNS server address to
4.4.4.41
-
The auto-configuration value to
none
. No auto-configuration is required when IP networking is configured statically.
ip=10.10.10.2::10.10.10.254:255.255.255.0:core0.example.com:enp1s0:none nameserver=4.4.4.41
When you use DHCP to configure IP addressing for the RHCOS machines, the machines also obtain the DNS server information through DHCP. For DHCP-based deployments, you can define the DNS server address that is used by the RHCOS nodes through your DHCP server configuration.
Configuring an IP address without a static hostname
You can configure an IP address without assigning a static hostname. If a static hostname is not set by the user, it will be picked up and automatically set by a reverse DNS lookup. To configure an IP address without a static hostname refer to the following example:
-
The node’s IP address to
10.10.10.2
-
The gateway address to
10.10.10.254
-
The netmask to
255.255.255.0
-
The DNS server address to
4.4.4.41
-
The auto-configuration value to
none
. No auto-configuration is required when IP networking is configured statically.
ip=10.10.10.2::10.10.10.254:255.255.255.0::enp1s0:none nameserver=4.4.4.41
Specifying multiple network interfaces
You can specify multiple network interfaces by setting multiple ip=
entries.
ip=10.10.10.2::10.10.10.254:255.255.255.0:core0.example.com:enp1s0:none ip=10.10.10.3::10.10.10.254:255.255.255.0:core0.example.com:enp2s0:none
Configuring default gateway and route
Optional: You can configure routes to additional networks by setting an rd.route=
value.
When you configure one or multiple networks, one default gateway is required. If the additional network gateway is different from the primary network gateway, the default gateway must be the primary network gateway.
Run the following command to configure the default gateway:
ip=::10.10.10.254::::
Enter the following command to configure the route for the additional network:
rd.route=20.20.20.0/24:20.20.20.254:enp2s0
Disabling DHCP on a single interface
You can disable DHCP on a single interface, such as when there are two or more network interfaces and only one interface is being used. In the example, the enp1s0
interface has a static networking configuration and DHCP is disabled for enp2s0
, which is not used:
ip=10.10.10.2::10.10.10.254:255.255.255.0:core0.example.com:enp1s0:none ip=::::core0.example.com:enp2s0:none
Combining DHCP and static IP configurations
You can combine DHCP and static IP configurations on systems with multiple network interfaces, for example:
ip=enp1s0:dhcp ip=10.10.10.2::10.10.10.254:255.255.255.0:core0.example.com:enp2s0:none
Configuring VLANs on individual interfaces
Optional: You can configure VLANs on individual interfaces by using the vlan=
parameter.
To configure a VLAN on a network interface and use a static IP address, run the following command:
ip=10.10.10.2::10.10.10.254:255.255.255.0:core0.example.com:enp2s0.100:none vlan=enp2s0.100:enp2s0
To configure a VLAN on a network interface and to use DHCP, run the following command:
ip=enp2s0.100:dhcp vlan=enp2s0.100:enp2s0
Providing multiple DNS servers
You can provide multiple DNS servers by adding a nameserver=
entry for each server, for example:
nameserver=1.1.1.1 nameserver=8.8.8.8
Bonding multiple network interfaces to a single interface
Optional: You can bond multiple network interfaces to a single interface by using the bond=
option. Refer to the following examples:
The syntax for configuring a bonded interface is:
bond=<name>[:<network_interfaces>][:options]
<name>
is the bonding device name (bond0
),<network_interfaces>
represents a comma-separated list of physical (ethernet) interfaces (em1,em2
), and options is a comma-separated list of bonding options. Entermodinfo bonding
to see available options.When you create a bonded interface using
bond=
, you must specify how the IP address is assigned and other information for the bonded interface.To configure the bonded interface to use DHCP, set the bond’s IP address to
dhcp
. For example:bond=bond0:em1,em2:mode=active-backup ip=bond0:dhcp
To configure the bonded interface to use a static IP address, enter the specific IP address you want and related information. For example:
bond=bond0:em1,em2:mode=active-backup ip=10.10.10.2::10.10.10.254:255.255.255.0:core0.example.com:bond0:none
Bonding multiple SR-IOV network interfaces to a dual port NIC interface
Support for Day 1 operations associated with enabling NIC partitioning for SR-IOV devices is a Technology Preview feature only. Technology Preview features are not supported with Red Hat production service level agreements (SLAs) and might not be functionally complete. Red Hat does not recommend using them in production. These features provide early access to upcoming product features, enabling customers to test functionality and provide feedback during the development process.
For more information about the support scope of Red Hat Technology Preview features, see Technology Preview Features Support Scope.
Optional: You can bond multiple SR-IOV network interfaces to a dual port NIC interface by using the bond=
option.
On each node, you must perform the following tasks:
- Create the SR-IOV virtual functions (VFs) following the guidance in Managing SR-IOV devices. Follow the procedure in the "Attaching SR-IOV networking devices to virtual machines" section.
- Create the bond, attach the desired VFs to the bond and set the bond link state up following the guidance in Configuring network bonding. Follow any of the described procedures to create the bond.
The following examples illustrate the syntax you must use:
The syntax for configuring a bonded interface is
bond=<name>[:<network_interfaces>][:options]
.<name>
is the bonding device name (bond0
),<network_interfaces>
represents the virtual functions (VFs) by their known name in the kernel and shown in the output of theip link
command(eno1f0
,eno2f0
), and options is a comma-separated list of bonding options. Entermodinfo bonding
to see available options.When you create a bonded interface using
bond=
, you must specify how the IP address is assigned and other information for the bonded interface.To configure the bonded interface to use DHCP, set the bond’s IP address to
dhcp
. For example:bond=bond0:eno1f0,eno2f0:mode=active-backup ip=bond0:dhcp
To configure the bonded interface to use a static IP address, enter the specific IP address you want and related information. For example:
bond=bond0:eno1f0,eno2f0:mode=active-backup ip=10.10.10.2::10.10.10.254:255.255.255.0:core0.example.com:bond0:none
Using network teaming
Optional: You can use a network teaming as an alternative to bonding by using the team=
parameter:
The syntax for configuring a team interface is:
team=name[:network_interfaces]
name is the team device name (
team0
) and network_interfaces represents a comma-separated list of physical (ethernet) interfaces (em1, em2
).
Teaming is planned to be deprecated when RHCOS switches to an upcoming version of RHEL. For more information, see this Red Hat Knowledgebase Article.
Use the following example to configure a network team:
team=team0:em1,em2 ip=team0:dhcp
4.11.3.9.2. coreos-installer
options for ISO and PXE installations
You can install RHCOS by running coreos-installer install <options> <device>
at the command prompt, after booting into the RHCOS live environment from an ISO image.
The following table shows the subcommands, options, and arguments you can pass to the coreos-installer
command.
coreos-installer install subcommand | |
Subcommand | Description |
| Embed an Ignition config in an ISO image. |
coreos-installer install subcommand options | |
Option | Description |
| Specify the image URL manually. |
| Specify a local image file manually. Used for debugging. |
| Embed an Ignition config from a file. |
| Embed an Ignition config from a URL. |
|
Digest |
| Override the Ignition platform ID for the installed system. |
|
Set the kernel and bootloader console for the installed system. For more information about the format of |
| Append a default kernel argument to the installed system. |
| Delete a default kernel argument from the installed system. |
| Copy the network configuration from the install environment. Important
The |
|
For use with |
| Save partitions with this label glob. |
| Save partitions with this number or range. |
| Skip RHCOS image signature verification. |
| Allow Ignition URL without HTTPS or hash. |
|
Target CPU architecture. Valid values are |
| Do not clear partition table on error. |
| Print help information. |
coreos-installer install subcommand argument | |
Argument | Description |
| The destination device. |
coreos-installer ISO subcommands | |
Subcommand | Description |
| Customize a RHCOS live ISO image. |
| Restore a RHCOS live ISO image to default settings. |
| Remove the embedded Ignition config from an ISO image. |
coreos-installer ISO customize subcommand options | |
Option | Description |
| Merge the specified Ignition config file into a new configuration fragment for the destination system. |
| Specify the kernel and bootloader console for the destination system. |
| Install and overwrite the specified destination device. |
| Add a kernel argument to each boot of the destination system. |
| Delete a kernel argument from each boot of the destination system. |
| Configure networking by using the specified NetworkManager keyfile for live and destination systems. |
| Specify an additional TLS certificate authority to be trusted by Ignition. |
| Run the specified script before installation. |
| Run the specified script after installation. |
| Apply the specified installer configuration file. |
| Merge the specified Ignition config file into a new configuration fragment for the live environment. |
| Add a kernel argument to each boot of the live environment. |
| Delete a kernel argument from each boot of the live environment. |
|
Replace a kernel argument in each boot of the live environment, in the form |
| Overwrite an existing Ignition config. |
| Write the ISO to a new output file. |
| Print help information. |
coreos-installer PXE subcommands | |
Subcommand | Description |
Note that not all of these options are accepted by all subcommands. | |
| Customize a RHCOS live PXE boot config. |
| Wrap an Ignition config in an image. |
| Show the wrapped Ignition config in an image. |
coreos-installer PXE customize subcommand options | |
Option | Description |
Note that not all of these options are accepted by all subcommands. | |
| Merge the specified Ignition config file into a new configuration fragment for the destination system. |
| Specify the kernel and bootloader console for the destination system. |
| Install and overwrite the specified destination device. |
| Configure networking by using the specified NetworkManager keyfile for live and destination systems. |
| Specify an additional TLS certificate authority to be trusted by Ignition. |
| Run the specified script before installation. |
| Run the specified script after installation. |
| Apply the specified installer configuration file. |
| Merge the specified Ignition config file into a new configuration fragment for the live environment. |
| Write the initramfs to a new output file. Note This option is required for PXE environments. |
| Print help information. |
4.11.3.9.3. coreos.inst
boot options for ISO or PXE installations
You can automatically invoke coreos-installer
options at boot time by passing coreos.inst
boot arguments to the RHCOS live installer. These are provided in addition to the standard boot arguments.
-
For ISO installations, the
coreos.inst
options can be added by interrupting the automatic boot at the bootloader menu. You can interrupt the automatic boot by pressingTAB
while the RHEL CoreOS (Live) menu option is highlighted. -
For PXE or iPXE installations, the
coreos.inst
options must be added to theAPPEND
line before the RHCOS live installer is booted.
The following table shows the RHCOS live installer coreos.inst
boot options for ISO and PXE installations.
Argument | Description |
---|---|
|
Required. The block device on the system to install to. It is recommended to use the full path, such as |
| Optional: The URL of the Ignition config to embed into the installed system. If no URL is specified, no Ignition config is embedded. Only HTTP and HTTPS protocols are supported. |
| Optional: Comma-separated labels of partitions to preserve during the install. Glob-style wildcards are permitted. The specified partitions do not need to exist. |
|
Optional: Comma-separated indexes of partitions to preserve during the install. Ranges |
|
Optional: Permits the OS image that is specified by |
| Optional: Download and install the specified RHCOS image.
|
| Optional: The system will not reboot after installing. After the install finishes, you will receive a prompt that allows you to inspect what is happening during installation. This argument should not be used in production environments and is intended for debugging purposes only. |
|
Optional: The Ignition platform ID of the platform the RHCOS image is being installed on. Default is |
|
Optional: The URL of the Ignition config for the live boot. For example, this can be used to customize how |
4.11.4. Enabling multipathing with kernel arguments on RHCOS
RHCOS supports multipathing on the primary disk, allowing stronger resilience to hardware failure to achieve higher host availability.
You can enable multipathing at installation time for nodes that were provisioned in OpenShift Container Platform 4.8 or later. While postinstallation support is available by activating multipathing via the machine config, enabling multipathing during installation is recommended.
In setups where any I/O to non-optimized paths results in I/O system errors, you must enable multipathing at installation time.
On IBM Z and IBM® LinuxONE, you can enable multipathing only if you configured your cluster for it during installation. For more information, see "Installing RHCOS and starting the OpenShift Container Platform bootstrap process" in Installing a cluster with z/VM on IBM Z and IBM® LinuxONE.
The following procedure enables multipath at installation time and appends kernel arguments to the coreos-installer install
command so that the installed system itself will use multipath beginning from the first boot.
OpenShift Container Platform does not support enabling multipathing as a day-2 activity on nodes that have been upgraded from 4.6 or earlier.
Prerequisites
- You have created the Ignition config files for your cluster.
- You have reviewed Installing RHCOS and starting the OpenShift Container Platform bootstrap process.
Procedure
To enable multipath and start the
multipathd
daemon, run the following command on the installation host:$ mpathconf --enable && systemctl start multipathd.service
-
Optional: If booting the PXE or ISO, you can instead enable multipath by adding
rd.multipath=default
from the kernel command line.
-
Optional: If booting the PXE or ISO, you can instead enable multipath by adding
Append the kernel arguments by invoking the
coreos-installer
program:If there is only one multipath device connected to the machine, it should be available at path
/dev/mapper/mpatha
. For example:$ coreos-installer install /dev/mapper/mpatha \1 --ignition-url=http://host/worker.ign \ --append-karg rd.multipath=default \ --append-karg root=/dev/disk/by-label/dm-mpath-root \ --append-karg rw
- 1
- Indicates the path of the single multipathed device.
If there are multiple multipath devices connected to the machine, or to be more explicit, instead of using
/dev/mapper/mpatha
, it is recommended to use the World Wide Name (WWN) symlink available in/dev/disk/by-id
. For example:$ coreos-installer install /dev/disk/by-id/wwn-<wwn_ID> \1 --ignition-url=http://host/worker.ign \ --append-karg rd.multipath=default \ --append-karg root=/dev/disk/by-label/dm-mpath-root \ --append-karg rw
- 1
- Indicates the WWN ID of the target multipathed device. For example,
0xx194e957fcedb4841
.
This symlink can also be used as the
coreos.inst.install_dev
kernel argument when using specialcoreos.inst.*
arguments to direct the live installer. For more information, see "Installing RHCOS and starting the OpenShift Container Platform bootstrap process".
- Reboot into the installed system.
Check that the kernel arguments worked by going to one of the worker nodes and listing the kernel command line arguments (in
/proc/cmdline
on the host):$ oc debug node/ip-10-0-141-105.ec2.internal
Example output
Starting pod/ip-10-0-141-105ec2internal-debug ... To use host binaries, run `chroot /host` sh-4.2# cat /host/proc/cmdline ... rd.multipath=default root=/dev/disk/by-label/dm-mpath-root ... sh-4.2# exit
You should see the added kernel arguments.
4.11.4.1. Enabling multipathing on secondary disks
RHCOS also supports multipathing on a secondary disk. Instead of kernel arguments, you use Ignition to enable multipathing for the secondary disk at installation time.
Prerequisites
- You have read the section Disk partitioning.
- You have read Enabling multipathing with kernel arguments on RHCOS.
- You have installed the Butane utility.
Procedure
Create a Butane config with information similar to the following:
Example
multipath-config.bu
variant: openshift version: 4.13.0 systemd: units: - name: mpath-configure.service enabled: true contents: | [Unit] Description=Configure Multipath on Secondary Disk ConditionFirstBoot=true ConditionPathExists=!/etc/multipath.conf Before=multipathd.service 1 DefaultDependencies=no [Service] Type=oneshot ExecStart=/usr/sbin/mpathconf --enable 2 [Install] WantedBy=multi-user.target - name: mpath-var-lib-container.service enabled: true contents: | [Unit] Description=Set Up Multipath On /var/lib/containers ConditionFirstBoot=true 3 Requires=dev-mapper-mpatha.device After=dev-mapper-mpatha.device After=ostree-remount.service Before=kubelet.service DefaultDependencies=no [Service] 4 Type=oneshot ExecStart=/usr/sbin/mkfs.xfs -L containers -m reflink=1 /dev/mapper/mpatha ExecStart=/usr/bin/mkdir -p /var/lib/containers [Install] WantedBy=multi-user.target - name: var-lib-containers.mount enabled: true contents: | [Unit] Description=Mount /var/lib/containers After=mpath-var-lib-containers.service Before=kubelet.service 5 [Mount] 6 What=/dev/disk/by-label/dm-mpath-containers Where=/var/lib/containers Type=xfs [Install] WantedBy=multi-user.target
- 1
- The configuration must be set before launching the multipath daemon.
- 2
- Starts the
mpathconf
utility. - 3
- This field must be set to the value
true
. - 4
- Creates the filesystem and directory
/var/lib/containers
. - 5
- The device must be mounted before starting any nodes.
- 6
- Mounts the device to the
/var/lib/containers
mount point. This location cannot be a symlink.
Create the Ignition configuration by running the following command:
$ butane --pretty --strict multipath-config.bu > multipath-config.ign
Continue with the rest of the first boot RHCOS installation process.
ImportantDo not add the
rd.multipath
orroot
kernel arguments on the command-line during installation unless the primary disk is also multipathed.
4.12. Waiting for the bootstrap process to complete
The OpenShift Container Platform bootstrap process begins after the cluster nodes first boot into the persistent RHCOS environment that has been installed to disk. The configuration information provided through the Ignition config files is used to initialize the bootstrap process and install OpenShift Container Platform on the machines. You must wait for the bootstrap process to complete.
Prerequisites
- You have created the Ignition config files for your cluster.
- You have configured suitable network, DNS and load balancing infrastructure.
- You have obtained the installation program and generated the Ignition config files for your cluster.
- You installed RHCOS on your cluster machines and provided the Ignition config files that the OpenShift Container Platform installation program generated.
Procedure
Monitor the bootstrap process:
$ ./openshift-install --dir <installation_directory> wait-for bootstrap-complete \ 1 --log-level=info 2
Example output
INFO Waiting up to 30m0s for the Kubernetes API at https://api.test.example.com:6443... INFO API v1.26.0 up INFO Waiting up to 30m0s for bootstrapping to complete... INFO It is now safe to remove the bootstrap resources
The command succeeds when the Kubernetes API server signals that it has been bootstrapped on the control plane machines.
After the bootstrap process is complete, remove the bootstrap machine from the load balancer.
ImportantYou must remove the bootstrap machine from the load balancer at this point. You can also remove or reformat the bootstrap machine itself.
Additional resources
- See Monitoring installation progress for more information about monitoring the installation logs and retrieving diagnostic data if installation issues arise.
4.13. Logging in to the cluster by using the CLI
You can log in to your cluster as a default system user by exporting the cluster kubeconfig
file. The kubeconfig
file contains information about the cluster that is used by the CLI to connect a client to the correct cluster and API server. The file is specific to a cluster and is created during OpenShift Container Platform installation.
Prerequisites
- You deployed an OpenShift Container Platform cluster.
-
You installed the
oc
CLI.
Procedure
Export the
kubeadmin
credentials:$ export KUBECONFIG=<installation_directory>/auth/kubeconfig 1
- 1
- For
<installation_directory>
, specify the path to the directory that you stored the installation files in.
Verify you can run
oc
commands successfully using the exported configuration:$ oc whoami
Example output
system:admin
4.14. Approving the certificate signing requests for your machines
When you add machines to a cluster, two pending certificate signing requests (CSRs) are generated for each machine that you added. You must confirm that these CSRs are approved or, if necessary, approve them yourself. The client requests must be approved first, followed by the server requests.
Prerequisites
- You added machines to your cluster.
Procedure
Confirm that the cluster recognizes the machines:
$ oc get nodes
Example output
NAME STATUS ROLES AGE VERSION master-0 Ready master 63m v1.26.0 master-1 Ready master 63m v1.26.0 master-2 Ready master 64m v1.26.0
The output lists all of the machines that you created.
NoteThe preceding output might not include the compute nodes, also known as worker nodes, until some CSRs are approved.
Review the pending CSRs and ensure that you see the client requests with the
Pending
orApproved
status for each machine that you added to the cluster:$ oc get csr
Example output
NAME AGE REQUESTOR CONDITION csr-8b2br 15m system:serviceaccount:openshift-machine-config-operator:node-bootstrapper Pending csr-8vnps 15m system:serviceaccount:openshift-machine-config-operator:node-bootstrapper Pending ...
In this example, two machines are joining the cluster. You might see more approved CSRs in the list.
If the CSRs were not approved, after all of the pending CSRs for the machines you added are in
Pending
status, approve the CSRs for your cluster machines:NoteBecause the CSRs rotate automatically, approve your CSRs within an hour of adding the machines to the cluster. If you do not approve them within an hour, the certificates will rotate, and more than two certificates will be present for each node. You must approve all of these certificates. After the client CSR is approved, the Kubelet creates a secondary CSR for the serving certificate, which requires manual approval. Then, subsequent serving certificate renewal requests are automatically approved by the
machine-approver
if the Kubelet requests a new certificate with identical parameters.NoteFor clusters running on platforms that are not machine API enabled, such as bare metal and other user-provisioned infrastructure, you must implement a method of automatically approving the kubelet serving certificate requests (CSRs). If a request is not approved, then the
oc exec
,oc rsh
, andoc logs
commands cannot succeed, because a serving certificate is required when the API server connects to the kubelet. Any operation that contacts the Kubelet endpoint requires this certificate approval to be in place. The method must watch for new CSRs, confirm that the CSR was submitted by thenode-bootstrapper
service account in thesystem:node
orsystem:admin
groups, and confirm the identity of the node.To approve them individually, run the following command for each valid CSR:
$ oc adm certificate approve <csr_name> 1
- 1
<csr_name>
is the name of a CSR from the list of current CSRs.
To approve all pending CSRs, run the following command:
$ oc get csr -o go-template='{{range .items}}{{if not .status}}{{.metadata.name}}{{"\n"}}{{end}}{{end}}' | xargs --no-run-if-empty oc adm certificate approve
NoteSome Operators might not become available until some CSRs are approved.
Now that your client requests are approved, you must review the server requests for each machine that you added to the cluster:
$ oc get csr
Example output
NAME AGE REQUESTOR CONDITION csr-bfd72 5m26s system:node:ip-10-0-50-126.us-east-2.compute.internal Pending csr-c57lv 5m26s system:node:ip-10-0-95-157.us-east-2.compute.internal Pending ...
If the remaining CSRs are not approved, and are in the
Pending
status, approve the CSRs for your cluster machines:To approve them individually, run the following command for each valid CSR:
$ oc adm certificate approve <csr_name> 1
- 1
<csr_name>
is the name of a CSR from the list of current CSRs.
To approve all pending CSRs, run the following command:
$ oc get csr -o go-template='{{range .items}}{{if not .status}}{{.metadata.name}}{{"\n"}}{{end}}{{end}}' | xargs oc adm certificate approve
After all client and server CSRs have been approved, the machines have the
Ready
status. Verify this by running the following command:$ oc get nodes
Example output
NAME STATUS ROLES AGE VERSION master-0 Ready master 73m v1.26.0 master-1 Ready master 73m v1.26.0 master-2 Ready master 74m v1.26.0 worker-0 Ready worker 11m v1.26.0 worker-1 Ready worker 11m v1.26.0
NoteIt can take a few minutes after approval of the server CSRs for the machines to transition to the
Ready
status.
Additional information
- For more information on CSRs, see Certificate Signing Requests.
4.15. Initial Operator configuration
After the control plane initializes, you must immediately configure some Operators so that they all become available.
Prerequisites
- Your control plane has initialized.
Procedure
Watch the cluster components come online:
$ watch -n5 oc get clusteroperators
Example output
NAME VERSION AVAILABLE PROGRESSING DEGRADED SINCE authentication 4.13.0 True False False 19m baremetal 4.13.0 True False False 37m cloud-credential 4.13.0 True False False 40m cluster-autoscaler 4.13.0 True False False 37m config-operator 4.13.0 True False False 38m console 4.13.0 True False False 26m csi-snapshot-controller 4.13.0 True False False 37m dns 4.13.0 True False False 37m etcd 4.13.0 True False False 36m image-registry 4.13.0 True False False 31m ingress 4.13.0 True False False 30m insights 4.13.0 True False False 31m kube-apiserver 4.13.0 True False False 26m kube-controller-manager 4.13.0 True False False 36m kube-scheduler 4.13.0 True False False 36m kube-storage-version-migrator 4.13.0 True False False 37m machine-api 4.13.0 True False False 29m machine-approver 4.13.0 True False False 37m machine-config 4.13.0 True False False 36m marketplace 4.13.0 True False False 37m monitoring 4.13.0 True False False 29m network 4.13.0 True False False 38m node-tuning 4.13.0 True False False 37m openshift-apiserver 4.13.0 True False False 32m openshift-controller-manager 4.13.0 True False False 30m openshift-samples 4.13.0 True False False 32m operator-lifecycle-manager 4.13.0 True False False 37m operator-lifecycle-manager-catalog 4.13.0 True False False 37m operator-lifecycle-manager-packageserver 4.13.0 True False False 32m service-ca 4.13.0 True False False 38m storage 4.13.0 True False False 37m
- Configure the Operators that are not available.
Additional resources
- See Gathering logs from a failed installation for details about gathering data in the event of a failed OpenShift Container Platform installation.
- See Troubleshooting Operator issues for steps to check Operator pod health across the cluster and gather Operator logs for diagnosis.
4.15.1. Disabling the default OperatorHub catalog sources
Operator catalogs that source content provided by Red Hat and community projects are configured for OperatorHub by default during an OpenShift Container Platform installation. In a restricted network environment, you must disable the default catalogs as a cluster administrator.
Procedure
Disable the sources for the default catalogs by adding
disableAllDefaultSources: true
to theOperatorHub
object:$ oc patch OperatorHub cluster --type json \ -p '[{"op": "add", "path": "/spec/disableAllDefaultSources", "value": true}]'
Alternatively, you can use the web console to manage catalog sources. From the Administration → Cluster Settings → Configuration → OperatorHub page, click the Sources tab, where you can create, update, delete, disable, and enable individual sources.
4.15.2. Image registry storage configuration
The Image Registry Operator is not initially available for platforms that do not provide default storage. After installation, you must configure your registry to use storage so that the Registry Operator is made available.
Instructions are shown for configuring a persistent volume, which is required for production clusters. Where applicable, instructions are shown for configuring an empty directory as the storage location, which is available for only non-production clusters.
Additional instructions are provided for allowing the image registry to use block storage types by using the Recreate
rollout strategy during upgrades.
4.15.2.1. Changing the image registry’s management state
To start the image registry, you must change the Image Registry Operator configuration’s managementState
from Removed
to Managed
.
Procedure
Change
managementState
Image Registry Operator configuration fromRemoved
toManaged
. For example:$ oc patch configs.imageregistry.operator.openshift.io cluster --type merge --patch '{"spec":{"managementState":"Managed"}}'
4.15.2.2. Configuring registry storage for bare metal and other manual installations
As a cluster administrator, following installation you must configure your registry to use storage.
Prerequisites
-
You have access to the cluster as a user with the
cluster-admin
role. - You have a cluster that uses manually-provisioned Red Hat Enterprise Linux CoreOS (RHCOS) nodes, such as bare metal.
You have provisioned persistent storage for your cluster, such as Red Hat OpenShift Data Foundation.
ImportantOpenShift Container Platform supports
ReadWriteOnce
access for image registry storage when you have only one replica.ReadWriteOnce
access also requires that the registry uses theRecreate
rollout strategy. To deploy an image registry that supports high availability with two or more replicas,ReadWriteMany
access is required.- Must have 100Gi capacity.
Procedure
To configure your registry to use storage, change the
spec.storage.pvc
in theconfigs.imageregistry/cluster
resource.NoteWhen you use shared storage, review your security settings to prevent outside access.
Verify that you do not have a registry pod:
$ oc get pod -n openshift-image-registry -l docker-registry=default
Example output
No resources found in openshift-image-registry namespace
NoteIf you do have a registry pod in your output, you do not need to continue with this procedure.
Check the registry configuration:
$ oc edit configs.imageregistry.operator.openshift.io
Example output
storage: pvc: claim:
Leave the
claim
field blank to allow the automatic creation of animage-registry-storage
PVC.Check the
clusteroperator
status:$ oc get clusteroperator image-registry
Example output
NAME VERSION AVAILABLE PROGRESSING DEGRADED SINCE MESSAGE image-registry 4.13 True False False 6h50m
Ensure that your registry is set to managed to enable building and pushing of images.
Run:
$ oc edit configs.imageregistry/cluster
Then, change the line
managementState: Removed
to
managementState: Managed
4.15.2.3. Configuring storage for the image registry in non-production clusters
You must configure storage for the Image Registry Operator. For non-production clusters, you can set the image registry to an empty directory. If you do so, all images are lost if you restart the registry.
Procedure
To set the image registry storage to an empty directory:
$ oc patch configs.imageregistry.operator.openshift.io cluster --type merge --patch '{"spec":{"storage":{"emptyDir":{}}}}'
WarningConfigure this option for only non-production clusters.
If you run this command before the Image Registry Operator initializes its components, the
oc patch
command fails with the following error:Error from server (NotFound): configs.imageregistry.operator.openshift.io "cluster" not found
Wait a few minutes and run the command again.
4.15.2.4. Configuring block registry storage for bare metal
To allow the image registry to use block storage types during upgrades as a cluster administrator, you can use the Recreate
rollout strategy.
Block storage volumes, or block persistent volumes, are supported but not recommended for use with the image registry on production clusters. An installation where the registry is configured on block storage is not highly available because the registry cannot have more than one replica.
If you choose to use a block storage volume with the image registry, you must use a filesystem persistent volume claim (PVC).
Procedure
Enter the following command to set the image registry storage as a block storage type, patch the registry so that it uses the
Recreate
rollout strategy, and runs with only one (1
) replica:$ oc patch config.imageregistry.operator.openshift.io/cluster --type=merge -p '{"spec":{"rolloutStrategy":"Recreate","replicas":1}}'
Provision the PV for the block storage device, and create a PVC for that volume. The requested block volume uses the ReadWriteOnce (RWO) access mode.
Create a
pvc.yaml
file with the following contents to define a VMware vSpherePersistentVolumeClaim
object:kind: PersistentVolumeClaim apiVersion: v1 metadata: name: image-registry-storage 1 namespace: openshift-image-registry 2 spec: accessModes: - ReadWriteOnce 3 resources: requests: storage: 100Gi 4
- 1
- A unique name that represents the
PersistentVolumeClaim
object. - 2
- The namespace for the
PersistentVolumeClaim
object, which isopenshift-image-registry
. - 3
- The access mode of the persistent volume claim. With
ReadWriteOnce
, the volume can be mounted with read and write permissions by a single node. - 4
- The size of the persistent volume claim.
Enter the following command to create the
PersistentVolumeClaim
object from the file:$ oc create -f pvc.yaml -n openshift-image-registry
Enter the following command to edit the registry configuration so that it references the correct PVC:
$ oc edit config.imageregistry.operator.openshift.io -o yaml
Example output
storage: pvc: claim: 1
- 1
- By creating a custom PVC, you can leave the
claim
field blank for the default automatic creation of animage-registry-storage
PVC.
4.16. Completing installation on user-provisioned infrastructure
After you complete the Operator configuration, you can finish installing the cluster on infrastructure that you provide.
Prerequisites
- Your control plane has initialized.
- You have completed the initial Operator configuration.
Procedure
Confirm that all the cluster components are online with the following command:
$ watch -n5 oc get clusteroperators
Example output
NAME VERSION AVAILABLE PROGRESSING DEGRADED SINCE authentication 4.13.0 True False False 19m baremetal 4.13.0 True False False 37m cloud-credential 4.13.0 True False False 40m cluster-autoscaler 4.13.0 True False False 37m config-operator 4.13.0 True False False 38m console 4.13.0 True False False 26m csi-snapshot-controller 4.13.0 True False False 37m dns 4.13.0 True False False 37m etcd 4.13.0 True False False 36m image-registry 4.13.0 True False False 31m ingress 4.13.0 True False False 30m insights 4.13.0 True False False 31m kube-apiserver 4.13.0 True False False 26m kube-controller-manager 4.13.0 True False False 36m kube-scheduler 4.13.0 True False False 36m kube-storage-version-migrator 4.13.0 True False False 37m machine-api 4.13.0 True False False 29m machine-approver 4.13.0 True False False 37m machine-config 4.13.0 True False False 36m marketplace 4.13.0 True False False 37m monitoring 4.13.0 True False False 29m network 4.13.0 True False False 38m node-tuning 4.13.0 True False False 37m openshift-apiserver 4.13.0 True False False 32m openshift-controller-manager 4.13.0 True False False 30m openshift-samples 4.13.0 True False False 32m operator-lifecycle-manager 4.13.0 True False False 37m operator-lifecycle-manager-catalog 4.13.0 True False False 37m operator-lifecycle-manager-packageserver 4.13.0 True False False 32m service-ca 4.13.0 True False False 38m storage 4.13.0 True False False 37m
Alternatively, the following command notifies you when all of the clusters are available. It also retrieves and displays credentials:
$ ./openshift-install --dir <installation_directory> wait-for install-complete 1
- 1
- For
<installation_directory>
, specify the path to the directory that you stored the installation files in.
Example output
INFO Waiting up to 30m0s for the cluster to initialize...
The command succeeds when the Cluster Version Operator finishes deploying the OpenShift Container Platform cluster from Kubernetes API server.
Important-
The Ignition config files that the installation program generates contain certificates that expire after 24 hours, which are then renewed at that time. If the cluster is shut down before renewing the certificates and the cluster is later restarted after the 24 hours have elapsed, the cluster automatically recovers the expired certificates. The exception is that you must manually approve the pending
node-bootstrapper
certificate signing requests (CSRs) to recover kubelet certificates. See the documentation for Recovering from expired control plane certificates for more information. - It is recommended that you use Ignition config files within 12 hours after they are generated because the 24-hour certificate rotates from 16 to 22 hours after the cluster is installed. By using the Ignition config files within 12 hours, you can avoid installation failure if the certificate update runs during installation.
Confirm that the Kubernetes API server is communicating with the pods.
To view a list of all pods, use the following command:
$ oc get pods --all-namespaces
Example output
NAMESPACE NAME READY STATUS RESTARTS AGE openshift-apiserver-operator openshift-apiserver-operator-85cb746d55-zqhs8 1/1 Running 1 9m openshift-apiserver apiserver-67b9g 1/1 Running 0 3m openshift-apiserver apiserver-ljcmx 1/1 Running 0 1m openshift-apiserver apiserver-z25h4 1/1 Running 0 2m openshift-authentication-operator authentication-operator-69d5d8bf84-vh2n8 1/1 Running 0 5m ...
View the logs for a pod that is listed in the output of the previous command by using the following command:
$ oc logs <pod_name> -n <namespace> 1
- 1
- Specify the pod name and namespace, as shown in the output of the previous command.
If the pod logs display, the Kubernetes API server can communicate with the cluster machines.
For an installation with Fibre Channel Protocol (FCP), additional steps are required to enable multipathing. Do not enable multipathing during installation.
See "Enabling multipathing with kernel arguments on RHCOS" in the Post-installation machine configuration tasks documentation for more information.
- Register your cluster on the Cluster registration page.
4.17. Telemetry access for OpenShift Container Platform
In OpenShift Container Platform 4.13, the Telemetry service, which runs by default to provide metrics about cluster health and the success of updates, requires internet access. If your cluster is connected to the internet, Telemetry runs automatically, and your cluster is registered to OpenShift Cluster Manager Hybrid Cloud Console.
After you confirm that your OpenShift Cluster Manager Hybrid Cloud Console inventory is correct, either maintained automatically by Telemetry or manually by using OpenShift Cluster Manager, use subscription watch to track your OpenShift Container Platform subscriptions at the account or multi-cluster level.
Additional resources
- See About remote health monitoring for more information about the Telemetry service
4.18. Next steps
- Validating an installation.
- Customize your cluster.
-
Configure image streams for the Cluster Samples Operator and the
must-gather
tool. - Learn how to use Operator Lifecycle Manager (OLM) on restricted networks.
- If the mirror registry that you used to install your cluster has a trusted CA, add it to the cluster by configuring additional trust stores.
- If necessary, you can opt out of remote health reporting.
- If necessary, see Registering your disconnected cluster
Chapter 5. Scaling a user-provisioned cluster with the Bare Metal Operator
After deploying a user-provisioned infrastructure cluster, you can use the Bare Metal Operator (BMO) and other metal3 components to scale bare-metal hosts in the cluster. This approach helps you to scale a user-provisioned cluster in a more automated way.
5.1. About scaling a user-provisioned cluster with the Bare Metal Operator
You can scale user-provisioned infrastructure clusters by using the Bare Metal Operator (BMO) and other metal3 components. User-provisioned infrastructure installations do not feature the Machine API Operator. The Machine API Operator typically manages the lifecycle of bare-metal hosts in a cluster. However, it is possible to use the BMO and other metal3 components to scale nodes in user-provisioned clusters without requiring the Machine API Operator.
5.1.1. Prerequisites for scaling a user-provisioned cluster
- You installed a user-provisioned infrastructure cluster on bare metal.
- You have baseboard management controller (BMC) access to the hosts.
5.1.2. Limitations for scaling a user-provisioned cluster
You cannot use a provisioning network to scale user-provisioned infrastructure clusters by using the Bare Metal Operator (BMO).
-
Consequentially, you can only use bare-metal host drivers that support virtual media networking booting, for example
redfish-virtualmedia
andidrac-virtualmedia
.
-
Consequentially, you can only use bare-metal host drivers that support virtual media networking booting, for example
-
You cannot scale
MachineSet
objects in user-provisioned infrastructure clusters by using the BMO.
5.2. Configuring a provisioning resource to scale user-provisioned clusters
Create a Provisioning
custom resource (CR) to enable Metal platform components on a user-provisioned infrastructure cluster.
Prerequisites
- You installed a user-provisioned infrastructure cluster on bare metal.
Procedure
Create a
Provisioning
CR.Save the following YAML in the
provisioning.yaml
file:apiVersion: metal3.io/v1alpha1 kind: Provisioning metadata: name: provisioning-configuration spec: provisioningNetwork: "Disabled" watchAllNamespaces: false
NoteOpenShift Container Platform 4.13 does not support enabling a provisioning network when you scale a user-provisioned cluster by using the Bare Metal Operator.
Create the
Provisioning
CR by running the following command:$ oc create -f provisioning.yaml
Example output
provisioning.metal3.io/provisioning-configuration created
Verification
Verify that the provisioning service is running by running the following command:
$ oc get pods -n openshift-machine-api
Example output
NAME READY STATUS RESTARTS AGE cluster-autoscaler-operator-678c476f4c-jjdn5 2/2 Running 0 5d21h cluster-baremetal-operator-6866f7b976-gmvgh 2/2 Running 0 5d21h control-plane-machine-set-operator-7d8566696c-bh4jz 1/1 Running 0 5d21h ironic-proxy-64bdw 1/1 Running 0 5d21h ironic-proxy-rbggf 1/1 Running 0 5d21h ironic-proxy-vj54c 1/1 Running 0 5d21h machine-api-controllers-544d6849d5-tgj9l 7/7 Running 1 (5d21h ago) 5d21h machine-api-operator-5c4ff4b86d-6fjmq 2/2 Running 0 5d21h metal3-6d98f84cc8-zn2mx 5/5 Running 0 5d21h metal3-image-customization-59d745768d-bhrp7 1/1 Running 0 5d21h
5.3. Provisioning new hosts in a user-provisioned cluster by using the BMO
You can use the Bare Metal Operator (BMO) to provision bare-metal hosts in a user-provisioned cluster by creating a BareMetalHost
custom resource (CR).
To provision bare-metal hosts to the cluster by using the BMO, you must set the spec.externallyProvisioned
specification in the BareMetalHost
custom resource to false
.
Prerequisites
- You created a user-provisioned bare-metal cluster.
- You have baseboard management controller (BMC) access to the hosts.
-
You deployed a provisioning service in the cluster by creating a
Provisioning
CR.
Procedure
Create the
Secret
CR and theBareMetalHost
CR.Save the following YAML in the
bmh.yaml
file:--- apiVersion: v1 kind: Secret metadata: name: worker1-bmc namespace: openshift-machine-api type: Opaque data: username: <base64_of_uid> password: <base64_of_pwd> --- apiVersion: metal3.io/v1alpha1 kind: BareMetalHost metadata: name: worker1 namespace: openshift-machine-api spec: bmc: address: <protocol>://<bmc_url> 1 credentialsName: "worker1-bmc" bootMACAddress: <nic1_mac_address> externallyProvisioned: false 2 customDeploy: method: install_coreos online: true userData: name: worker-user-data-managed namespace: openshift-machine-api
Create the bare-metal host object by running the following command:
$ oc create -f bmh.yaml
Example output
secret/worker1-bmc created baremetalhost.metal3.io/worker1 created
Approve all certificate signing requests (CSRs).
Verify that the provisioning state of the host is
provisioned
by running the following command:$ oc get bmh -A
Example output
NAMESPACE NAME STATE CONSUMER ONLINE ERROR AGE openshift-machine-api controller1 externally provisioned true 5m25s openshift-machine-api worker1 provisioned true 4m45s
Get the list of pending CSRs by running the following command:
$ oc get csr
Example output
NAME AGE SIGNERNAME REQUESTOR REQUESTEDDURATION CONDITION csr-gfm9f 33s kubernetes.io/kube-apiserver-client-kubelet system:serviceaccount:openshift-machine-config-o perator:node-bootstrapper <none> Pending
Approve the CSR by running the following command:
$ oc adm certificate approve <csr_name>
Example output
certificatesigningrequest.certificates.k8s.io/<csr_name> approved
Verification
Verify that the node is ready by running the following command:
$ oc get nodes
Example output
NAME STATUS ROLES AGE VERSION app1 Ready worker 47s v1.24.0+dc5a2fd controller1 Ready master,worker 2d22h v1.24.0+dc5a2fd
5.4. Optional: Managing existing hosts in a user-provisioned cluster by using the BMO
Optionally, you can use the Bare Metal Operator (BMO) to manage existing bare-metal controller hosts in a user-provisioned cluster by creating a BareMetalHost
object for the existing host. It is not a requirement to manage existing user-provisioned hosts; however, you can enroll them as externally-provisioned hosts for inventory purposes.
To manage existing hosts by using the BMO, you must set the spec.externallyProvisioned
specification in the BareMetalHost
custom resource to true
to prevent the BMO from re-provisioning the host.
Prerequisites
- You created a user-provisioned bare-metal cluster.
- You have baseboard management controller (BMC) access to the hosts.
-
You deployed a provisioning service in the cluster by creating a
Provisioning
CR.
Procedure
Create the
Secret
CR and theBareMetalHost
CR.Save the following YAML in the
controller.yaml
file:--- apiVersion: v1 kind: Secret metadata: name: controller1-bmc namespace: openshift-machine-api type: Opaque data: username: <base64_of_uid> password: <base64_of_pwd> --- apiVersion: metal3.io/v1alpha1 kind: BareMetalHost metadata: name: controller1 namespace: openshift-machine-api spec: bmc: address: <protocol>://<bmc_url> 1 credentialsName: "controller1-bmc" bootMACAddress: <nic1_mac_address> customDeploy: method: install_coreos externallyProvisioned: true 2 online: true userData: name: controller-user-data-managed namespace: openshift-machine-api
Create the bare-metal host object by running the following command:
$ oc create -f controller.yaml
Example output
secret/controller1-bmc created baremetalhost.metal3.io/controller1 created
Verification
Verify that the BMO created the bare-metal host object by running the following command:
$ oc get bmh -A
Example output
NAMESPACE NAME STATE CONSUMER ONLINE ERROR AGE openshift-machine-api controller1 externally provisioned true 13s
5.5. Removing hosts from a user-provisioned cluster by using the BMO
You can use the Bare Metal Operator (BMO) to remove bare-metal hosts from a user-provisioned cluster.
Prerequisites
- You created a user-provisioned bare-metal cluster.
- You have baseboard management controller (BMC) access to the hosts.
-
You deployed a provisioning service in the cluster by creating a
Provisioning
CR.
Procedure
Cordon and drain the host by running the following command:
$ oc adm drain app1 --force --ignore-daemonsets=true
Example output
node/app1 cordoned WARNING: ignoring DaemonSet-managed Pods: openshift-cluster-node-tuning-operator/tuned-tvthg, openshift-dns/dns- default-9q6rz, openshift-dns/node-resolver-zvt42, openshift-image-registry/node-ca-mzxth, openshift-ingress-cana ry/ingress-canary-qq5lf, openshift-machine-config-operator/machine-config-daemon-v79dm, openshift-monitoring/nod e-exporter-2vn59, openshift-multus/multus-additional-cni-plugins-wssvj, openshift-multus/multus-fn8tg, openshift -multus/network-metrics-daemon-5qv55, openshift-network-diagnostics/network-check-target-jqxn2, openshift-ovn-ku bernetes/ovnkube-node-rsvqg evicting pod openshift-operator-lifecycle-manager/collect-profiles-27766965-258vp evicting pod openshift-operator-lifecycle-manager/collect-profiles-27766950-kg5mk evicting pod openshift-operator-lifecycle-manager/collect-profiles-27766935-stf4s pod/collect-profiles-27766965-258vp evicted pod/collect-profiles-27766950-kg5mk evicted pod/collect-profiles-27766935-stf4s evicted node/app1 drained
Delete the
customDeploy
specification from theBareMetalHost
CR.Edit the
BareMetalHost
CR for the host by running the following command:$ oc edit bmh -n openshift-machine-api <host_name>
Delete the lines
spec.customDeploy
andspec.customDeploy.method
:... customDeploy: method: install_coreos
Verify that the provisioning state of the host changes to
deprovisioning
by running the following command:$ oc get bmh -A
Example output
NAMESPACE NAME STATE CONSUMER ONLINE ERROR AGE openshift-machine-api controller1 externally provisioned true 58m openshift-machine-api worker1 deprovisioning true 57m
Delete the node by running the following command:
$ oc delete node <node_name>
Verification
Verify the node is deleted by running the following command:
$ oc get nodes
Example output
NAME STATUS ROLES AGE VERSION controller1 Ready master,worker 2d23h v1.24.0+dc5a2fd
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