Chapter 7. Installing on IBM Power
7.1. Installing a cluster on IBM Power
In OpenShift Container Platform version 4.5, you can install a cluster on IBM Power infrastructure that you provision.
Additional considerations exist for non-bare metal platforms. Review the information in the guidelines for deploying OpenShift Container Platform on non-tested platforms before you install an OpenShift Container Platform cluster.
Prerequisites
- Before you begin the installation process, you must move or remove any existing installation files. This ensures that the required installation files are created and updated during the installation process.
-
Provision persistent storage using NFS for your cluster. To deploy a private image registry, your storage must provide
ReadWriteMany
access modes. - Review details about the OpenShift Container Platform installation and update processes.
If you use a firewall, you must configure 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.
7.1.1. Internet and Telemetry access for OpenShift Container Platform
In OpenShift Container Platform 4.5, you require access to the Internet to install your cluster. The Telemetry service, which runs by default to provide metrics about cluster health and the success of updates, also requires Internet access. If your cluster is connected to the Internet, Telemetry runs automatically, and your cluster is registered to the Red Hat OpenShift Cluster Manager (OCM).
Once you confirm that your Red Hat OpenShift Cluster Manager inventory is correct, either maintained automatically by Telemetry or manually using OCM, use subscription watch to track your OpenShift Container Platform subscriptions at the account or multi-cluster level.
You must have Internet access to:
- Access the Red Hat OpenShift Cluster Manager page 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 content that is required and use it to populate a mirror registry with the packages that you need to install a cluster and generate the installation program. 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.
7.1.2. Machine requirements for a cluster with user-provisioned infrastructure
For a cluster that contains user-provisioned infrastructure, you must deploy all of the required machines.
7.1.2.1. Required machines
The smallest OpenShift Container Platform clusters require the following hosts:
- One temporary bootstrap machine
- Three control plane, or master, machines
- At least two compute machines, which are also known as worker machines.
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.
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.
Note that RHCOS is based on Red Hat Enterprise Linux (RHEL) 8 and inherits all of its hardware certifications and requirements. See Red Hat Enterprise Linux technology capabilities and limits.
7.1.2.2. Network connectivity requirements
All the Red Hat Enterprise Linux CoreOS (RHCOS) machines require network in initramfs
during boot to fetch Ignition config files from the Machine Config Server. During the initial boot, the machines require either a DHCP server or that static IP addresses be set in order to establish a network connection to download their Ignition config files. Additionally, each OpenShift Container Platform node in the cluster must have access to a Network Time Protocol (NTP) server. If a DHCP server provides NTP servers 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.
7.1.2.3. Minimum resource requirements
Each cluster machine must meet the following minimum requirements:
Machine | Operating System | vCPU [1] | Virtual RAM | Storage |
---|---|---|---|---|
Bootstrap | RHCOS | 2 | 16 GB | 120 GB |
Control plane | RHCOS | 2 | 16 GB | 120 GB |
Compute | RHCOS | 2 | 8 GB | 120 GB |
- 1 vCPU is equivalent to 1 physical core when simultaneous multithreading (SMT), or hyperthreading, is not enabled. When enabled, use the following formula to calculate the corresponding ratio: (threads per core × cores) × sockets = vCPUs.
7.1.2.4. 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.
7.1.3. Creating the user-provisioned infrastructure
Before you deploy an OpenShift Container Platform cluster that uses user-provisioned infrastructure, you must create the underlying infrastructure.
Prerequisites
- Review the OpenShift Container Platform 4.x Tested Integrations page before you create the supporting infrastructure for your cluster.
Procedure
- Configure DHCP or set static IP addresses on each node.
- Provision the required load balancers.
- Configure the ports for your machines.
- Configure DNS.
- Ensure network connectivity.
7.1.3.1. Networking requirements for user-provisioned infrastructure
All the Red Hat Enterprise Linux CoreOS (RHCOS) machines require network in initramfs
during boot to fetch Ignition config from the machine config server.
You must configure the network connectivity between machines to allow cluster components to communicate. Each machine must be able to resolve the host names of all other machines in the cluster.
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 and Geneve |
| VXLAN and Geneve | |
|
Host level services, including the node exporter on ports | |
TCP/UDP |
| Kubernetes node port |
Protocol | Port | Description |
---|---|---|
TCP |
| Kubernetes API |
Protocol | Port | Description |
---|---|---|
TCP |
| etcd server and peer ports |
Network topology requirements
The infrastructure that you provision for your cluster must meet the following network topology requirements.
OpenShift Container Platform requires all nodes to have internet access to pull images for platform containers and provide telemetry data to Red Hat.
Load balancers
Before you install OpenShift Container Platform, you must provision two load balancers that 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, SSL Passthrough, or SSL Bridge mode. If you use SSL Bridge mode, you must enable Server Name Indication (SNI) for the API routes.
- A stateless load balancing algorithm. The options vary based on the load balancer implementation.
NoteSession persistence is not required for the API load balancer to function properly.
Configure the following ports on both the front and back of the load balancers:
Table 7.4. 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. Configure the following conditions:
- Layer 4 load balancing only. This can be referred to as Raw TCP, SSL Passthrough, or SSL Bridge mode. If you use SSL Bridge mode, you must enable Server Name Indication (SNI) for the Ingress routes.
- 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.
Configure the following ports on both the front and back of the load balancers:
Table 7.5. Application Ingress load balancer Port Back-end machines (pool members) Internal External Description 443
The machines that run the Ingress router pods, compute, or worker, by default.
X
X
HTTPS traffic
80
The machines that run the Ingress router pods, compute, or worker, by default.
X
X
HTTP traffic
If the true IP address of the client can be seen by the load balancer, enabling source IP-based session persistence can improve performance for applications that use end-to-end TLS encryption.
A working configuration for the Ingress router is required for an OpenShift Container Platform cluster. You must configure the Ingress router after the control plane initializes.
Additional resources
7.1.3.2. User-provisioned DNS requirements
DNS is used for name resolution and reverse name resolution. 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 host name for all the nodes. Additionally, the reverse records are used to generate the certificate signing requests (CSR) that OpenShift Container Platform needs to operate.
The following DNS records are required for an OpenShift Container Platform cluster that uses user-provisioned infrastructure. In each record, <cluster_name>
is the cluster name and <base_domain>
is the cluster 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 |
| Add a DNS A/AAAA or CNAME record, and a DNS PTR record, to identify the load balancer for the control plane machines. These records must be resolvable by both clients external to the cluster and from all the nodes within the cluster. |
| Add a DNS A/AAAA or CNAME record, and a DNS PTR record, to identify the load balancer for the control plane machines. 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 host names 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 |
| Add a wildcard DNS A/AAAA or CNAME record that refers to the load balancer that targets the machines that run the Ingress router pods, which are the worker nodes by default. These records must be resolvable by both clients external to the cluster and from all the nodes within the cluster. |
Bootstrap |
| Add 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. |
Master hosts |
| Add DNS A/AAAA or CNAME records and DNS PTR records to identify each machine for the master nodes. These records must be resolvable by the nodes within the cluster. |
Worker hosts |
| Add 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. |
You can use the nslookup <hostname>
command to verify name resolution. You can use the dig -x <ip_address>
command to verify reverse name resolution for the PTR records.
The following example of a BIND zone file shows sample A records for name resolution. The purpose of the example is to show the records that are needed. The example is not meant to provide advice for choosing one name resolution service over another.
Example 7.1. 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 IN A 192.168.1.5 smtp IN A 192.168.1.5 ; helper IN A 192.168.1.5 helper.ocp4 IN A 192.168.1.5 ; ; The api identifies the IP of your load balancer. api.ocp4 IN A 192.168.1.5 api-int.ocp4 IN A 192.168.1.5 ; ; The wildcard also identifies the load balancer. *.apps.ocp4 IN A 192.168.1.5 ; ; Create an entry for the bootstrap host. bootstrap.ocp4 IN A 192.168.1.96 ; ; Create entries for the master hosts. master0.ocp4 IN A 192.168.1.97 master1.ocp4 IN A 192.168.1.98 master2.ocp4 IN A 192.168.1.99 ; ; Create entries for the worker hosts. worker0.ocp4 IN A 192.168.1.11 worker1.ocp4 IN A 192.168.1.7 ; ;EOF
The following example BIND zone file shows sample PTR records for reverse name resolution.
Example 7.2. 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. ; ; The syntax is "last octet" and the host must have an FQDN ; with a trailing dot. 97 IN PTR master0.ocp4.example.com. 98 IN PTR master1.ocp4.example.com. 99 IN PTR master2.ocp4.example.com. ; 96 IN PTR bootstrap.ocp4.example.com. ; 5 IN PTR api.ocp4.example.com. 5 IN PTR api-int.ocp4.example.com. ; 11 IN PTR worker0.ocp4.example.com. 7 IN PTR worker1.ocp4.example.com. ; ;EOF
7.1.4. Generating an SSH private key and adding it to the agent
If you want to perform installation debugging or disaster recovery on your cluster, you must provide an SSH key to both your ssh-agent
and the installation program. You can use this key to access the bootstrap machine in a public cluster to troubleshoot installation issues.
In a production environment, you require disaster recovery and debugging.
You can use this key to SSH into the master nodes as the user core
. When you deploy the cluster, the key is added to the core
user’s ~/.ssh/authorized_keys
list.
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 SSH key that is configured for password-less authentication on your computer, 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_rsa
, of the new SSH key. If you have an existing key pair, ensure your public key is in the your~/.ssh
directory.
Running this command generates an SSH key that does not require a password in the location that you specified.
NoteIf you plan to install an OpenShift Container Platform cluster that uses FIPS Validated / Modules in Process cryptographic libraries on the
x86_64
architecture, do not create a key that uses theed25519
algorithm. Instead, create a key that uses thersa
orecdsa
algorithm.Start the
ssh-agent
process as a background task:$ eval "$(ssh-agent -s)"
Example output
Agent pid 31874
If your cluster is in FIPS mode, only use FIPS-compliant algorithms to generate the SSH key. The key must be either RSA or ECDSA.
Add your SSH private key to the
ssh-agent
:$ ssh-add <path>/<file_name> 1
Example output
Identity added: /home/<you>/<path>/<file_name> (<computer_name>)
- 1
- Specify the path and file name for your SSH private key, such as
~/.ssh/id_rsa
Set the
GOOGLE_APPLICATION_CREDENTIALS
environment variable to the full path to your service account private key file.$ export GOOGLE_APPLICATION_CREDENTIALS="<your_service_account_file>"
Verify that the credentials were applied.
$ gcloud auth list
Next steps
- When you install OpenShift Container Platform, provide the SSH public key to the installation program.
7.1.5. Obtaining the installation program
Before you install OpenShift Container Platform, download the installation file on a local computer.
Prerequisites
- You must install the cluster from a computer that uses Linux or macOS.
- You need 500 MB of local disk space to download the installation program.
Procedure
- Access the Infrastructure Provider page on the Red Hat OpenShift Cluster Manager site. If you have a Red Hat account, log in with your credentials. If you do not, create an account.
Navigate to the page for your installation type, download the installation program for your operating system, 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 both the installation program and the files that the installation program creates after you finish installing the cluster.
ImportantDeleting the files created by the installation program does not remove your cluster, even if the cluster failed during installation. You must complete the OpenShift Container Platform uninstallation procedures outlined for your specific cloud provider to remove your cluster entirely.
Extract the installation program. For example, on a computer that uses a Linux operating system, run the following command:
$ tar xvf <installation_program>.tar.gz
-
From the Pull Secret page on the Red Hat OpenShift Cluster Manager site, download your installation pull secret as a
.txt
file. 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.
7.1.6. Installing the CLI by downloading the binary
You can install the OpenShift CLI (oc
) in order 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 4.5. Download and install the new version of oc
.
7.1.6.1. Installing the CLI on Linux
You can install the OpenShift CLI (oc
) binary on Linux by using the following procedure.
Procedure
- Navigate to the Infrastructure Provider page on the Red Hat OpenShift Cluster Manager site.
- Select your infrastructure provider, and, if applicable, your installation type.
- In the Command line interface section, select Linux from the drop-down menu and click Download command-line tools.
Unpack the archive:
$ tar xvzf <file>
Place the
oc
binary in a directory that is on yourPATH
.To check your
PATH
, execute the following command:$ echo $PATH
After you install the CLI, it is available using the oc
command:
$ oc <command>
7.1.6.2. Installing the CLI on Windows
You can install the OpenShift CLI (oc
) binary on Windows by using the following procedure.
Procedure
- Navigate to the Infrastructure Provider page on the Red Hat OpenShift Cluster Manager site.
- Select your infrastructure provider, and, if applicable, your installation type.
- In the Command line interface section, select Windows from the drop-down menu and click Download command-line tools.
- 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
After you install the CLI, it is available using the oc
command:
C:\> oc <command>
7.1.6.3. Installing the CLI on macOS
You can install the OpenShift CLI (oc
) binary on macOS by using the following procedure.
Procedure
- Navigate to the Infrastructure Provider page on the Red Hat OpenShift Cluster Manager site.
- Select your infrastructure provider, and, if applicable, your installation type.
- In the Command line interface section, select MacOS from the drop-down menu and click Download command-line tools.
- 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
After you install the CLI, it is available using the oc
command:
$ oc <command>
7.1.7. Manually creating the installation configuration file
For installations of OpenShift Container Platform that use user-provisioned infrastructure, you manually generate your installation configuration file.
Prerequisites
- Obtain the OpenShift Container Platform installation program and the access token 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 following
install-config.yaml
file template 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.
7.1.7.1. Sample install-config.yaml
file for IBM Power
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: OpenShiftSDN serviceNetwork: 11 - 172.30.0.0/16 platform: none: {} 12 fips: false 13 pullSecret: '{"auths": ...}' 14 sshKey: 'ssh-ed25519 AAAA...' 15
- 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. Although both sections currently define a single machine pool, it is possible that future versions of OpenShift Container Platform will support defining multiple compute pools during installation. Only one control plane pool is used. - 3 6
- Whether to enable or disable simultaneous multithreading (SMT), or
hyperthreading
. By default, SMT is enabled to increase the performance of your machines' cores. You can disable it by setting the parameter value toDisabled
. 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
, ensure that your capacity planning accounts for the dramatically decreased machine performance. - 4
- You must set the value of the
replicas
parameter to0
. This parameter controls the number of workers that the cluster creates and manages for you, which are functions that the cluster does not perform when you use user-provisioned infrastructure. You must manually deploy worker machines for the cluster to use before you finish installing OpenShift Container Platform. - 7
- The number of control plane machines that you add to the cluster. Because the cluster uses this 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.
- 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 IPs 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 IP address pool to use for service IP addresses. You can enter only one IP address pool. If you need to access the services from an external network, configure load balancers and routers to manage the traffic.
- 12
- You must set the platform to
none
. You cannot provide additional platform configuration variables for IBM Power infrastructure. - 13
- Whether to enable or disable FIPS mode. By default, FIPS mode is not enabled. If FIPS mode is enabled, the Red Hat Enterprise Linux CoreOS (RHCOS) machines that OpenShift Container Platform runs on bypass the default Kubernetes cryptography suite and use the cryptography modules that are provided with RHCOS instead.
- 14
- The pull secret that you obtained from the Pull Secret page on the Red Hat OpenShift Cluster Manager site. 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.
- 15
- The public portion of the default SSH 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.
7.1.8. 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 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.
Prerequisites
- Obtain the OpenShift Container Platform installation program.
-
Create the
install-config.yaml
installation configuration file.
Procedure
Generate the Kubernetes manifests for the cluster:
$ ./openshift-install create manifests --dir=<installation_directory> 1
Example output
INFO Consuming Install Config from target directory WARNING Making control-plane schedulable by setting MastersSchedulable to true for Scheduler cluster settings
- 1
- For
<installation_directory>
, specify the installation directory that contains theinstall-config.yaml
file you created.
Because you create your own compute machines later in the installation process, you can safely ignore this warning.
Remove the Kubernetes manifest files that define the control plane machines:
$ rm -f <installation_directory>/openshift/99_openshift-cluster-api_master-machines-*.yaml
By removing these files, you prevent the cluster from automatically generating control plane machines.
Optional: If you do not want the cluster to provision compute machines, remove the Kubernetes manifest files that define the worker machines:
$ rm -f <installation_directory>/openshift/99_openshift-cluster-api_worker-machineset-*.yaml
Because you create and manage the worker machines yourself, you do not need to initialize these machines.
Modify the
<installation_directory>/manifests/cluster-scheduler-02-config.yml
Kubernetes manifest file to prevent 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 set its value toFalse
. - Save and exit the file.
-
Open the
Optional: If you do not want the Ingress Operator to create DNS records on your behalf, remove the
privateZone
andpublicZone
sections from the<installation_directory>/manifests/cluster-dns-02-config.yml
DNS configuration file:apiVersion: config.openshift.io/v1 kind: DNS metadata: creationTimestamp: null name: cluster spec: baseDomain: example.openshift.com privateZone: 1 id: mycluster-100419-private-zone publicZone: 2 id: example.openshift.com status: {}
If you do so, you must add ingress DNS records manually in a later step.
Obtain the Ignition config files:
$ ./openshift-install create ignition-configs --dir=<installation_directory> 1
- 1
- For
<installation_directory>
, specify the same installation directory.
The following files are generated in the directory:
. ├── auth │ ├── kubeadmin-password │ └── kubeconfig ├── bootstrap.ign ├── master.ign ├── metadata.json └── worker.ign
7.1.9. Creating Red Hat Enterprise Linux CoreOS (RHCOS) machines
Before you install a cluster on IBM Power infrastructure that you provision, you must create RHCOS machines for it to use. Follow either the steps to use an ISO image or network PXE booting to create the machines.
7.1.9.1. Creating Red Hat Enterprise Linux CoreOS (RHCOS) machines using an ISO image
Before you install a cluster on IBM Power infrastructure that you provision, you must create RHCOS machines for it to use. You can use an ISO image to create the machines.
Prerequisites
- Obtain the Ignition config files for your cluster.
- Have access to an HTTP server that you can access from your computer and that the machines that you create can access.
Procedure
Upload the control plane, compute, and bootstrap Ignition config files that the installation program created to your HTTP server. Note the URLs of these files.
ImportantIf you plan to add more compute machines to your cluster after you finish installation, do not delete these files.
Obtain the RHCOS images that are required for your preferred method of installing operating system instances from the RHCOS image mirror page.
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. Only use ISO images for this procedure. RHCOS qcow2 images are not supported for bare metal installs.
You must download the ISO file and the RAW disk file. Those file names resemble the following examples:
-
ISO:
rhcos-<version>-installer.<architecture>.iso
-
Compressed metal RAW:
rhcos-<version>-metal.<architecture>.raw.gz
-
ISO:
Upload either the RAW RHCOS image file to your HTTP server and note its URL.
ImportantIf you plan to add more compute machines to your cluster after you finish installation, do not delete these files.
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 via a LOM interface.
-
After the instance boots, press the
TAB
orE
key to edit the kernel command line. Add the parameters to the kernel command line:
coreos.inst=yes coreos.inst.install_dev=sda 1 coreos.inst.image_url=<image_URL> 2 coreos.inst.ignition_url=http://example.com/config.ign 3 ip=<dhcp or static IP address> 4 5 bond=<bonded_interface> 6
- 1
- Specify the block device of the system to install to.
- 2
- Specify the URL of the RAW image that you uploaded to your server.
- 3
- Specify the URL of the Ignition config file for this machine type.
- 4
- Set
ip=dhcp
or set an individual static IP address (ip=
) and DNS server (nameserver=
) on each node. See Configure advanced networking for details. - 5
- If you use multiple network interfaces or DNS servers, see Configure advanced networking for details on how to configure them.
- 6
- Optionally, you can bond multiple network interfaces to a single interface using the
bond=
option, as described in Configure advanced networking.
- Press Enter to complete the installation. After RHCOS installs, the system reboots. After the system reboots, it applies the Ignition config file that you specified.
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, which is the default, also create at least two compute machines before you install the cluster.
7.1.9.2. Creating Red Hat Enterprise Linux CoreOS (RHCOS) machines by PXE booting
Before you install a cluster on IBM Power infrastructure that you provision, you must create RHCOS machines for it to use. You can use PXE booting to create the machines.
Prerequisites
- Obtain the Ignition config files for your cluster.
- Have access to an HTTP server and TFTP server that you can access from your computer.
Procedure
Upload the master, worker, and bootstrap Ignition config files that the installation program created to your HTTP server. Note the URLs of these files.
ImportantIf you plan to add more compute machines to your cluster after you finish installation, do not delete these files.
Obtain the compressed metal RAW image,
kernel
andinitramfs
files from the Product Downloads page on the Red Hat customer portal or the RHCOS image mirror page.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. Only use RAW images for this procedure. RHCOS qcow2 images are not supported for bare metal installs.
The file names contain the OpenShift Container Platform version number. They resemble the following examples:
-
Compressed metal RAW image:
rhcos-<version>-<architecture>-metal.<architecture>.raw.gz
-
kernel
:rhcos-<version>-<architecture>-installer-kernel-<architecture>
-
initramfs
:rhcos-<version>-<architecture>-installer-initramfs.<architecture>.img
-
Compressed metal RAW image:
- Upload the RAW image to your HTTP server.
Upload the additional files that are required for your booting method:
-
For traditional PXE, upload the
kernel
andinitramfs
files to your TFTP server. -
For iPXE, upload the
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.
-
For traditional PXE, upload the
- Configure the network boot infrastructure so that the machines boot from their local disks after RHCOS is installed on them.
Configure PXE installation for the RHCOS images.
Modify one of the following example menu entries for your environment and verify that the image and Ignition files are properly accessible:
For PXE:
DEFAULT pxeboot TIMEOUT 20 PROMPT 0 LABEL pxeboot KERNEL rhcos-<version>-<architecture>-installer-kernel-<architecture> 1 APPEND ip=dhcp rd.neednet=1 initrd=rhcos-<version>-<architecture>-installer-initramfs.<architecture>.img coreos.inst=yes coreos.inst.install_dev=sda coreos.inst.image_url=http://<HTTP_server>/rhcos-<version>-<architecture>-metal.<architecture>.raw.gz coreos.inst.ignition_url=http://<HTTP_server>/bootstrap.ign 2 3
- 1
- Specify the location of the
kernel
file available on your TFTP 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 locations of the RHCOS files that you uploaded to your HTTP or TFTP server. The
initrd
parameter value is the location of theinitramfs
file on your TFTP server. Thecoreos.inst.image_url
parameter value is the location of the compressed metal RAW image on your HTTP server, and thecoreos.inst.ignition_url
parameter value is the location of the bootstrap Ignition config file on 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 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?.
If you use UEFI, perform the following actions:
Provide the EFI binaries and
grub.cfg
file that are required for booting the system. You need theshim.efi
binary and thegrubx64.efi
binary.Extract the necessary EFI binaries by mounting the RHCOS ISO on your host and then mounting the
images/efiboot.img
file to your host. From theefiboot.img
mount point, you then copy theEFI/redhat/shimx64.efi
andEFI/redhat/grubx64.efi
files to your TFTP server.# mkdir -p /mnt/{iso,efiboot} # mount -o loop rhcos-installer.x86_64.iso /mnt/iso # mount -o loop,ro /mnt/iso/images/efiboot.img /mnt/efiboot # cp /mnt/efiboot/EFI/redhat/{shimx64.efi,grubx64.efi} . # umount /mnt/{efiboot,iso}
-
Copy the
EFI/redhat/grub.cfg
file that is included in the RHCOS ISO to your TFTP server. Edit the
grub.cfg
file to include the following arguments:menuentry 'Install Red Hat Enterprise Linux CoreOS' --class fedora --class gnu-linux --class gnu --class os { linux rhcos-<version>-<architecture>-installer-kernel-<architecture> nomodeset rd.neednet=1 coreos.inst=yes coreos.inst.install_dev=sda coreos.inst.image_url=http://<HTTP_server>/rhcos-<version>-<architecture>-metal.<architecture>.raw.gz coreos.inst.ignition_url=http://<HTTP_server>/bootstrap.ign 1 initrd rhcos-<version>-<architecture>-installer-initramfs.<architecture>.img 2 }
- 1
- The first argument to the
linux
line item is the location of thekernel
file that you uploaded to your TFTP server. For thecoreos.inst.image_url
parameter value, specify the location of the compressed metal RAW image that you uploaded to your HTTP server. For thecoreos.inst.ignition_url
paramter, specify the location of the bootstrap Ignition config file that you uploaded to your HTTP server. - 2
- Specify the location of the
initramfs
file that you uploaded to your TFTP server.
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, which is the default, also create at least two compute machines before you install the cluster.
7.1.10. Creating the cluster
To create the OpenShift Container Platform cluster, you wait for the bootstrap process to complete on the machines that you provisioned by using the Ignition config files that you generated with the installation program.
Prerequisites
- Create the required infrastructure for the cluster.
- You obtained the installation program and generated the Ignition config files for your cluster.
- You used the Ignition config files to create RHCOS machines for your cluster.
- 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 v1.18.3 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 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 machine itself.
7.1.11. Logging in to the cluster
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
- Deploy an OpenShift Container Platform cluster.
-
Install 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
7.1.12. 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 v1.18.3 master-1 Ready master 63m v1.18.3 master-2 Ready master 64m v1.18.3 worker-0 NotReady worker 76s v1.18.3 worker-1 NotReady worker 70s v1.18.3
The output lists all of the machines that you created.
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. Once 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.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
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 v1.20.0 master-1 Ready master 73m v1.20.0 master-2 Ready master 74m v1.20.0 worker-0 Ready worker 11m v1.20.0 worker-1 Ready worker 11m v1.20.0
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.
7.1.13. 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 4.5.4 True False False 69s cloud-credential 4.5.4 True False False 12m cluster-autoscaler 4.5.4 True False False 11m console 4.5.4 True False False 46s dns 4.5.4 True False False 11m image-registry 4.5.4 True False False 5m26s ingress 4.5.4 True False False 5m36s kube-apiserver 4.5.4 True False False 8m53s kube-controller-manager 4.5.4 True False False 7m24s kube-scheduler 4.5.4 True False False 12m machine-api 4.5.4 True False False 12m machine-config 4.5.4 True False False 7m36s marketplace 4.5.4 True False False 7m54m monitoring 4.5.4 True False False 7h54s network 4.5.4 True False False 5m9s node-tuning 4.5.4 True False False 11m openshift-apiserver 4.5.4 True False False 11m openshift-controller-manager 4.5.4 True False False 5m943s openshift-samples 4.5.4 True False False 3m55s operator-lifecycle-manager 4.5.4 True False False 11m operator-lifecycle-manager-catalog 4.5.4 True False False 11m service-ca 4.5.4 True False False 11m service-catalog-apiserver 4.5.4 True False False 5m26s service-catalog-controller-manager 4.5.4 True False False 5m25s storage 4.5.4 True False False 5m30s
- Configure the Operators that are not available.
7.1.13.1. 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.
7.1.13.1.1. Configuring registry storage for bare metal
As a cluster administrator, following installation you must configure your registry to use storage.
Prerequisites
- Cluster administrator permissions.
- A cluster on bare metal.
Persistent storage provisioned for your cluster, such as Red Hat OpenShift Container Storage.
ImportantOpenShift Container Platform supports
ReadWriteOnce
access for image registry storage when you have only one replica. 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 using 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
NoteIf the storage type is
emptyDIR
, the replica number cannot be greater than1
.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
7.1.13.1.2. 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.
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
7.1.14. 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 4.5.4 True False False 7m56s cloud-credential 4.5.4 True False False 31m cluster-autoscaler 4.5.4 True False False 16m console 4.5.4 True False False 10m csi-snapshot-controller 4.5.4 True False False 16m dns 4.5.4 True False False 22m etcd 4.5.4 False False False 25s image-registry 4.5.4 True False False 16m ingress 4.5.4 True False False 16m insights 4.5.4 True False False 17m kube-apiserver 4.5.4 True False False 19m kube-controller-manager 4.5.4 True False False 20m kube-scheduler 4.5.4 True False False 20m kube-storage-version-migrator 4.5.4 True False False 16m machine-api 4.5.4 True False False 22m machine-config 4.5.4 True False False 22m marketplace 4.5.4 True False False 16m monitoring 4.5.4 True False False 10m network 4.5.4 True False False 23m node-tuning 4.5.4 True False False 23m openshift-apiserver 4.5.4 True False False 17m openshift-controller-manager 4.5.4 True False False 15m openshift-samples 4.5.4 True False False 16m operator-lifecycle-manager 4.5.4 True False False 22m operator-lifecycle-manager-catalog 4.5.4 True False False 22m operator-lifecycle-manager-packageserver 4.5.4 True False False 18m service-ca 4.5.4 True False False 23m service-catalog-apiserver 4.5.4 True False False 23m service-catalog-controller-manager 4.5.4 True False False 23m storage 4.5.4 True False False 17m
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.
ImportantThe 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.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.
Next steps
- Customize your cluster.
- If necessary, you can opt out of remote health reporting.
7.2. Installing a cluster on IBM Power in a restricted network
In OpenShift Container Platform version 4.5, you can install a cluster on IBM Power infrastructure that you provision in a restricted network.
Additional considerations exist for non-bare metal platforms. Review the information in the guidelines for deploying OpenShift Container Platform on non-tested platforms before you install an OpenShift Container Platform cluster.
Prerequisites
-
Create a mirror registry for installation in a restricted network and obtain the
imageContentSources
data for your version of OpenShift Container Platform. Use thedocker.io/ibmcom/registry-ppc64le:2.6.2.5
image. Before you begin the installation process, you must move or remove any existing installation files. This ensures that the required installation files are created and updated during the installation process.
ImportantEnsure that installation steps are done from a machine with access to the installation media.
-
Provision persistent storage for your cluster. To deploy a private image registry, your storage must provide
ReadWriteMany
access modes. - Review details about the OpenShift Container Platform installation and update processes.
If you use a firewall and plan to use telemetry, you must configure 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.
7.2.1. About installations in restricted networks
In OpenShift Container Platform 4.5, 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.
To complete a restricted network installation, you must create a registry that mirrors the contents of the OpenShift Container Platform 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.
7.2.1.1. 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.
7.2.2. Machine requirements for a cluster with user-provisioned infrastructure
For a cluster that contains user-provisioned infrastructure, you must deploy all of the required machines.
7.2.2.1. Required machines
The smallest OpenShift Container Platform clusters require the following hosts:
- One temporary bootstrap machine
- Three control plane, or master, machines
- At least two compute machines, which are also known as worker machines.
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.
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.
Note that RHCOS is based on Red Hat Enterprise Linux (RHEL) 8 and inherits all of its hardware certifications and requirements. See Red Hat Enterprise Linux technology capabilities and limits.
7.2.2.2. Network connectivity requirements
All the Red Hat Enterprise Linux CoreOS (RHCOS) machines require network in initramfs
during boot to fetch Ignition config files from the Machine Config Server. During the initial boot, the machines require either a DHCP server or that static IP addresses be set in order to establish a network connection to download their Ignition config files. Additionally, each OpenShift Container Platform node in the cluster must have access to a Network Time Protocol (NTP) server. If a DHCP server provides NTP servers 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.
7.2.2.3. Minimum resource requirements
Each cluster machine must meet the following minimum requirements:
Machine | Operating System | vCPU [1] | Virtual RAM | Storage |
---|---|---|---|---|
Bootstrap | RHCOS | 2 | 16 GB | 120 GB |
Control plane | RHCOS | 2 | 16 GB | 120 GB |
Compute | RHCOS | 2 | 8 GB | 120 GB |
- 1 vCPU is equivalent to 1 physical core when simultaneous multithreading (SMT), or hyperthreading, is not enabled. When enabled, use the following formula to calculate the corresponding ratio: (threads per core × cores) × sockets = vCPUs.
7.2.2.4. 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.
7.2.3. Creating the user-provisioned infrastructure
Before you deploy an OpenShift Container Platform cluster that uses user-provisioned infrastructure, you must create the underlying infrastructure.
Prerequisites
- Review the OpenShift Container Platform 4.x Tested Integrations page before you create the supporting infrastructure for your cluster.
Procedure
- Configure DHCP or set static IP addresses on each node.
- Provision the required load balancers.
- Configure the ports for your machines.
- Configure DNS.
- Ensure network connectivity.
7.2.3.1. Networking requirements for user-provisioned infrastructure
All the Red Hat Enterprise Linux CoreOS (RHCOS) machines require network in initramfs
during boot to fetch Ignition config from the machine config server.
You must configure the network connectivity between machines to allow cluster components to communicate. Each machine must be able to resolve the host names of all other machines in the cluster.
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 and Geneve |
| VXLAN and Geneve | |
|
Host level services, including the node exporter on ports | |
TCP/UDP |
| Kubernetes node port |
Protocol | Port | Description |
---|---|---|
TCP |
| Kubernetes API |
Protocol | Port | Description |
---|---|---|
TCP |
| etcd server and peer ports |
Network topology requirements
The infrastructure that you provision for your cluster must meet the following network topology requirements.
Load balancers
Before you install OpenShift Container Platform, you must provision two load balancers that 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, SSL Passthrough, or SSL Bridge mode. If you use SSL Bridge mode, you must enable Server Name Indication (SNI) for the API routes.
- A stateless load balancing algorithm. The options vary based on the load balancer implementation.
NoteSession persistence is not required for the API load balancer to function properly.
Configure the following ports on both the front and back of the load balancers:
Table 7.10. 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. Configure the following conditions:
- Layer 4 load balancing only. This can be referred to as Raw TCP, SSL Passthrough, or SSL Bridge mode. If you use SSL Bridge mode, you must enable Server Name Indication (SNI) for the Ingress routes.
- 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.
Configure the following ports on both the front and back of the load balancers:
Table 7.11. Application Ingress load balancer Port Back-end machines (pool members) Internal External Description 443
The machines that run the Ingress router pods, compute, or worker, by default.
X
X
HTTPS traffic
80
The machines that run the Ingress router pods, compute, or worker, by default.
X
X
HTTP traffic
If the true IP address of the client can be seen by the load balancer, enabling source IP-based session persistence can improve performance for applications that use end-to-end TLS encryption.
A working configuration for the Ingress router is required for an OpenShift Container Platform cluster. You must configure the Ingress router after the control plane initializes.
Additional resources
7.2.3.2. User-provisioned DNS requirements
DNS is used for name resolution and reverse name resolution. 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 host name for all the nodes. Additionally, the reverse records are used to generate the certificate signing requests (CSR) that OpenShift Container Platform needs to operate.
The following DNS records are required for an OpenShift Container Platform cluster that uses user-provisioned infrastructure. In each record, <cluster_name>
is the cluster name and <base_domain>
is the cluster 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 |
| Add a DNS A/AAAA or CNAME record, and a DNS PTR record, to identify the load balancer for the control plane machines. These records must be resolvable by both clients external to the cluster and from all the nodes within the cluster. |
| Add a DNS A/AAAA or CNAME record, and a DNS PTR record, to identify the load balancer for the control plane machines. 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 host names 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 |
| Add a wildcard DNS A/AAAA or CNAME record that refers to the load balancer that targets the machines that run the Ingress router pods, which are the worker nodes by default. These records must be resolvable by both clients external to the cluster and from all the nodes within the cluster. |
Bootstrap |
| Add 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. |
Master hosts |
| Add DNS A/AAAA or CNAME records and DNS PTR records to identify each machine for the master nodes. These records must be resolvable by the nodes within the cluster. |
Worker hosts |
| Add 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. |
You can use the nslookup <hostname>
command to verify name resolution. You can use the dig -x <ip_address>
command to verify reverse name resolution for the PTR records.
The following example of a BIND zone file shows sample A records for name resolution. The purpose of the example is to show the records that are needed. The example is not meant to provide advice for choosing one name resolution service over another.
Example 7.3. 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 IN A 192.168.1.5 smtp IN A 192.168.1.5 ; helper IN A 192.168.1.5 helper.ocp4 IN A 192.168.1.5 ; ; The api identifies the IP of your load balancer. api.ocp4 IN A 192.168.1.5 api-int.ocp4 IN A 192.168.1.5 ; ; The wildcard also identifies the load balancer. *.apps.ocp4 IN A 192.168.1.5 ; ; Create an entry for the bootstrap host. bootstrap.ocp4 IN A 192.168.1.96 ; ; Create entries for the master hosts. master0.ocp4 IN A 192.168.1.97 master1.ocp4 IN A 192.168.1.98 master2.ocp4 IN A 192.168.1.99 ; ; Create entries for the worker hosts. worker0.ocp4 IN A 192.168.1.11 worker1.ocp4 IN A 192.168.1.7 ; ;EOF
The following example BIND zone file shows sample PTR records for reverse name resolution.
Example 7.4. 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. ; ; The syntax is "last octet" and the host must have an FQDN ; with a trailing dot. 97 IN PTR master0.ocp4.example.com. 98 IN PTR master1.ocp4.example.com. 99 IN PTR master2.ocp4.example.com. ; 96 IN PTR bootstrap.ocp4.example.com. ; 5 IN PTR api.ocp4.example.com. 5 IN PTR api-int.ocp4.example.com. ; 11 IN PTR worker0.ocp4.example.com. 7 IN PTR worker1.ocp4.example.com. ; ;EOF
7.2.4. Generating an SSH private key and adding it to the agent
If you want to perform installation debugging or disaster recovery on your cluster, you must provide an SSH key to both your ssh-agent
and the installation program. You can use this key to access the bootstrap machine in a public cluster to troubleshoot installation issues.
In a production environment, you require disaster recovery and debugging.
You can use this key to SSH into the master nodes as the user core
. When you deploy the cluster, the key is added to the core
user’s ~/.ssh/authorized_keys
list.
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 SSH key that is configured for password-less authentication on your computer, 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_rsa
, of the new SSH key. If you have an existing key pair, ensure your public key is in the your~/.ssh
directory.
Running this command generates an SSH key that does not require a password in the location that you specified.
NoteIf you plan to install an OpenShift Container Platform cluster that uses FIPS Validated / Modules in Process cryptographic libraries on the
x86_64
architecture, do not create a key that uses theed25519
algorithm. Instead, create a key that uses thersa
orecdsa
algorithm.Start the
ssh-agent
process as a background task:$ eval "$(ssh-agent -s)"
Example output
Agent pid 31874
If your cluster is in FIPS mode, only use FIPS-compliant algorithms to generate the SSH key. The key must be either RSA or ECDSA.
Add your SSH private key to the
ssh-agent
:$ ssh-add <path>/<file_name> 1
Example output
Identity added: /home/<you>/<path>/<file_name> (<computer_name>)
- 1
- Specify the path and file name for your SSH private key, such as
~/.ssh/id_rsa
Set the
GOOGLE_APPLICATION_CREDENTIALS
environment variable to the full path to your service account private key file.$ export GOOGLE_APPLICATION_CREDENTIALS="<your_service_account_file>"
Verify that the credentials were applied.
$ gcloud auth list
Next steps
- When you install OpenShift Container Platform, provide the SSH public key to the installation program.
7.2.5. Manually creating the installation configuration file
For installations of OpenShift Container Platform that use user-provisioned infrastructure, you manually generate your installation configuration file.
Prerequisites
- Obtain the OpenShift Container Platform installation program and the access token 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 following
install-config.yaml
file template 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.
7.2.5.1. Sample install-config.yaml
file for IBM Power
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: OpenShiftSDN serviceNetwork: 11 - 172.30.0.0/16 platform: none: {} 12 fips: false 13 pullSecret: '{"auths":{"<local_registry>": {"auth": "<credentials>","email": "you@example.com"}}}' 14 sshKey: 'ssh-ed25519 AAAA...' 15 additionalTrustBundle: | 16 -----BEGIN CERTIFICATE----- ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ -----END CERTIFICATE----- imageContentSources: 17 - mirrors: - <local_registry>/<local_repository_name>/release source: quay.io/openshift-release-dev/ocp-release - mirrors: - <local_registry>/<local_repository_name>/release source: registry.svc.ci.openshift.org/ocp/release
- 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. Although both sections currently define a single machine pool, it is possible that future versions of OpenShift Container Platform will support defining multiple compute pools during installation. Only one control plane pool is used. - 3 6
- Whether to enable or disable simultaneous multithreading (SMT), or
hyperthreading
. By default, SMT is enabled to increase the performance of your machines' cores. You can disable it by setting the parameter value toDisabled
. 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
, ensure that your capacity planning accounts for the dramatically decreased machine performance. - 4
- You must set the value of the
replicas
parameter to0
. This parameter controls the number of workers that the cluster creates and manages for you, which are functions that the cluster does not perform when you use user-provisioned infrastructure. You must manually deploy worker machines for the cluster to use before you finish installing OpenShift Container Platform. - 7
- The number of control plane machines that you add to the cluster. Because the cluster uses this 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.
- 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 IPs 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 IP address pool to use for service IP addresses. You can enter only one IP address pool. If you need to access the services from an external network, configure load balancers and routers to manage the traffic.
- 12
- You must set the platform to
none
. You cannot provide additional platform configuration variables for IBM Power infrastructure. - 13
- Whether to enable or disable FIPS mode. By default, FIPS mode is not enabled. If FIPS mode is enabled, the Red Hat Enterprise Linux CoreOS (RHCOS) machines that OpenShift Container Platform runs on bypass the default Kubernetes cryptography suite and use the cryptography modules that are provided with RHCOS instead.
- 14
- For
<local_registry>
, specify the registry domain name, and optionally the port, that your mirror registry uses to serve content. For exampleregistry.example.com
orregistry.example.com:5000
. For<credentials>
, specify the base64-encoded user name and password for your mirror registry. - 15
- The public portion of the default SSH 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. - 16
- Provide the contents of the certificate file that you used for your mirror registry.
- 17
- Provide the
imageContentSources
section from the output of the command to mirror the repository.
7.2.5.2. 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.
Prerequisites
-
An existing
install-config.yaml
file. Review the sites that your cluster requires access to and determine whether any need to bypass the proxy. By default, all cluster egress traffic is proxied, including calls to hosting cloud provider APIs. Add 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: http://<username>:<pswd>@<ip>:<port> 2 noProxy: example.com 3 additionalTrustBundle: | 4 -----BEGIN CERTIFICATE----- <MY_TRUSTED_CA_CERT> -----END CERTIFICATE----- ...
- 1
- A proxy URL to use for creating HTTP connections outside the cluster. The URL scheme must be
http
. If you use an MITM transparent proxy network that does not require additional proxy configuration but requires additional CAs, you must not specify anhttpProxy
value. - 2
- A proxy URL to use for creating HTTPS connections outside the cluster. If this field is not specified, then
httpProxy
is used for both HTTP and HTTPS connections. If you use an MITM transparent proxy network that does not require additional proxy configuration but requires additional CAs, you must not specify anhttpsProxy
value. - 3
- A comma-separated list of destination domain names, domains, IP addresses, or other network CIDRs to exclude proxying. Preface a domain with
.
to match subdomains only. For example,.y.com
matchesx.y.com
, but noty.com
. Use*
to bypass 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 theProxy
object’strustedCA
field. TheadditionalTrustBundle
field is required unless the proxy’s identity certificate is signed by an authority from the RHCOS trust bundle. If you use an MITM transparent proxy network that does not require additional proxy configuration but requires additional CAs, you must provide the MITM CA certificate.
NoteThe installation program does not support the proxy
readinessEndpoints
field.- 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.
7.2.6. 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 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.
Prerequisites
- Obtain the OpenShift Container Platform installation program. For a restricted network installation, these files are on your mirror host.
-
Create the
install-config.yaml
installation configuration file.
Procedure
Generate the Kubernetes manifests for the cluster:
$ ./openshift-install create manifests --dir=<installation_directory> 1
Example output
INFO Consuming Install Config from target directory WARNING Making control-plane schedulable by setting MastersSchedulable to true for Scheduler cluster settings
- 1
- For
<installation_directory>
, specify the installation directory that contains theinstall-config.yaml
file you created.
Because you create your own compute machines later in the installation process, you can safely ignore this warning.
Remove the Kubernetes manifest files that define the control plane machines:
$ rm -f <installation_directory>/openshift/99_openshift-cluster-api_master-machines-*.yaml
By removing these files, you prevent the cluster from automatically generating control plane machines.
Optional: If you do not want the cluster to provision compute machines, remove the Kubernetes manifest files that define the worker machines:
$ rm -f <installation_directory>/openshift/99_openshift-cluster-api_worker-machineset-*.yaml
Because you create and manage the worker machines yourself, you do not need to initialize these machines.
Modify the
<installation_directory>/manifests/cluster-scheduler-02-config.yml
Kubernetes manifest file to prevent 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 set its value toFalse
. - Save and exit the file.
-
Open the
Optional: If you do not want the Ingress Operator to create DNS records on your behalf, remove the
privateZone
andpublicZone
sections from the<installation_directory>/manifests/cluster-dns-02-config.yml
DNS configuration file:apiVersion: config.openshift.io/v1 kind: DNS metadata: creationTimestamp: null name: cluster spec: baseDomain: example.openshift.com privateZone: 1 id: mycluster-100419-private-zone publicZone: 2 id: example.openshift.com status: {}
If you do so, you must add ingress DNS records manually in a later step.
Obtain the Ignition config files:
$ ./openshift-install create ignition-configs --dir=<installation_directory> 1
- 1
- For
<installation_directory>
, specify the same installation directory.
The following files are generated in the directory:
. ├── auth │ ├── kubeadmin-password │ └── kubeconfig ├── bootstrap.ign ├── master.ign ├── metadata.json └── worker.ign
7.2.7. Creating Red Hat Enterprise Linux CoreOS (RHCOS) machines
Before you install a cluster on IBM Power infrastructure that you provision, you must create RHCOS machines for it to use. Follow either the steps to use an ISO image or network PXE booting to create the machines.
7.2.7.1. Creating Red Hat Enterprise Linux CoreOS (RHCOS) machines using an ISO image
Before you install a cluster on IBM Power infrastructure that you provision, you must create RHCOS machines for it to use. You can use an ISO image to create the machines.
Prerequisites
- Obtain the Ignition config files for your cluster.
- Have access to an HTTP server that you can access from your computer and that the machines that you create can access.
Procedure
Upload the control plane, compute, and bootstrap Ignition config files that the installation program created to your HTTP server. Note the URLs of these files.
ImportantIf you plan to add more compute machines to your cluster after you finish installation, do not delete these files.
Obtain the RHCOS images that are required for your preferred method of installing operating system instances from the RHCOS image mirror page.
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. Only use ISO images for this procedure. RHCOS qcow2 images are not supported for bare metal installs.
You must download the ISO file and the RAW disk file. Those file names resemble the following examples:
-
ISO:
rhcos-<version>-installer.<architecture>.iso
-
Compressed metal RAW:
rhcos-<version>-metal.<architecture>.raw.gz
-
ISO:
Upload either the RAW RHCOS image file to your HTTP server and note its URL.
ImportantIf you plan to add more compute machines to your cluster after you finish installation, do not delete these files.
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 via a LOM interface.
-
After the instance boots, press the
TAB
orE
key to edit the kernel command line. Add the parameters to the kernel command line:
coreos.inst=yes coreos.inst.install_dev=sda 1 coreos.inst.image_url=<image_URL> 2 coreos.inst.ignition_url=http://example.com/config.ign 3 ip=<dhcp or static IP address> 4 5 bond=<bonded_interface> 6
- 1
- Specify the block device of the system to install to.
- 2
- Specify the URL of the RAW image that you uploaded to your server.
- 3
- Specify the URL of the Ignition config file for this machine type.
- 4
- Set
ip=dhcp
or set an individual static IP address (ip=
) and DNS server (nameserver=
) on each node. See Configure advanced networking for details. - 5
- If you use multiple network interfaces or DNS servers, see Configure advanced networking for details on how to configure them.
- 6
- Optionally, you can bond multiple network interfaces to a single interface using the
bond=
option, as described in Configure advanced networking.
- Press Enter to complete the installation. After RHCOS installs, the system reboots. After the system reboots, it applies the Ignition config file that you specified.
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, which is the default, also create at least two compute machines before you install the cluster.
7.2.7.2. Creating Red Hat Enterprise Linux CoreOS (RHCOS) machines by PXE booting
Before you install a cluster on IBM Power infrastructure that you provision, you must create RHCOS machines for it to use. You can use PXE booting to create the machines.
Prerequisites
- Obtain the Ignition config files for your cluster.
- Have access to an HTTP server and TFTP server that you can access from your computer.
Procedure
Upload the master, worker, and bootstrap Ignition config files that the installation program created to your HTTP server. Note the URLs of these files.
ImportantIf you plan to add more compute machines to your cluster after you finish installation, do not delete these files.
Obtain the compressed metal RAW image,
kernel
andinitramfs
files from the Product Downloads page on the Red Hat customer portal or the RHCOS image mirror page.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. Only use RAW images for this procedure. RHCOS qcow2 images are not supported for bare metal installs.
The file names contain the OpenShift Container Platform version number. They resemble the following examples:
-
Compressed metal RAW image:
rhcos-<version>-<architecture>-metal.<architecture>.raw.gz
-
kernel
:rhcos-<version>-<architecture>-installer-kernel-<architecture>
-
initramfs
:rhcos-<version>-<architecture>-installer-initramfs.<architecture>.img
-
Compressed metal RAW image:
- Upload the RAW image to your HTTP server.
Upload the additional files that are required for your booting method:
-
For traditional PXE, upload the
kernel
andinitramfs
files to your TFTP server. -
For iPXE, upload the
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.
-
For traditional PXE, upload the
- Configure the network boot infrastructure so that the machines boot from their local disks after RHCOS is installed on them.
Configure PXE installation for the RHCOS images.
Modify one of the following example menu entries for your environment and verify that the image and Ignition files are properly accessible:
For PXE:
DEFAULT pxeboot TIMEOUT 20 PROMPT 0 LABEL pxeboot KERNEL rhcos-<version>-<architecture>-installer-kernel-<architecture> 1 APPEND ip=dhcp rd.neednet=1 initrd=rhcos-<version>-<architecture>-installer-initramfs.<architecture>.img coreos.inst=yes coreos.inst.install_dev=sda coreos.inst.image_url=http://<HTTP_server>/rhcos-<version>-<architecture>-metal.<architecture>.raw.gz coreos.inst.ignition_url=http://<HTTP_server>/bootstrap.ign 2 3
- 1
- Specify the location of the
kernel
file available on your TFTP 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 locations of the RHCOS files that you uploaded to your HTTP or TFTP server. The
initrd
parameter value is the location of theinitramfs
file on your TFTP server. Thecoreos.inst.image_url
parameter value is the location of the compressed metal RAW image on your HTTP server, and thecoreos.inst.ignition_url
parameter value is the location of the bootstrap Ignition config file on 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 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?.
If you use UEFI, perform the following actions:
Provide the EFI binaries and
grub.cfg
file that are required for booting the system. You need theshim.efi
binary and thegrubx64.efi
binary.Extract the necessary EFI binaries by mounting the RHCOS ISO on your host and then mounting the
images/efiboot.img
file to your host. From theefiboot.img
mount point, you then copy theEFI/redhat/shimx64.efi
andEFI/redhat/grubx64.efi
files to your TFTP server.# mkdir -p /mnt/{iso,efiboot} # mount -o loop rhcos-installer.x86_64.iso /mnt/iso # mount -o loop,ro /mnt/iso/images/efiboot.img /mnt/efiboot # cp /mnt/efiboot/EFI/redhat/{shimx64.efi,grubx64.efi} . # umount /mnt/{efiboot,iso}
-
Copy the
EFI/redhat/grub.cfg
file that is included in the RHCOS ISO to your TFTP server. Edit the
grub.cfg
file to include the following arguments:menuentry 'Install Red Hat Enterprise Linux CoreOS' --class fedora --class gnu-linux --class gnu --class os { linux rhcos-<version>-<architecture>-installer-kernel-<architecture> nomodeset rd.neednet=1 coreos.inst=yes coreos.inst.install_dev=sda coreos.inst.image_url=http://<HTTP_server>/rhcos-<version>-<architecture>-metal.<architecture>.raw.gz coreos.inst.ignition_url=http://<HTTP_server>/bootstrap.ign 1 initrd rhcos-<version>-<architecture>-installer-initramfs.<architecture>.img 2 }
- 1
- The first argument to the
linux
line item is the location of thekernel
file that you uploaded to your TFTP server. For thecoreos.inst.image_url
parameter value, specify the location of the compressed metal RAW image that you uploaded to your HTTP server. For thecoreos.inst.ignition_url
paramter, specify the location of the bootstrap Ignition config file that you uploaded to your HTTP server. - 2
- Specify the location of the
initramfs
file that you uploaded to your TFTP server.
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, which is the default, also create at least two compute machines before you install the cluster.
7.2.8. Creating the cluster
To create the OpenShift Container Platform cluster, you wait for the bootstrap process to complete on the machines that you provisioned by using the Ignition config files that you generated with the installation program.
Prerequisites
- Create the required infrastructure for the cluster.
- You obtained the installation program and generated the Ignition config files for your cluster.
- You used the Ignition config files to create RHCOS machines for your cluster.
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 v1.18.3 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 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 machine itself.
7.2.9. Logging in to the cluster
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
- Deploy an OpenShift Container Platform cluster.
-
Install 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
7.2.10. 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 v1.18.3 master-1 Ready master 63m v1.18.3 master-2 Ready master 64m v1.18.3 worker-0 NotReady worker 76s v1.18.3 worker-1 NotReady worker 70s v1.18.3
The output lists all of the machines that you created.
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. Once 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.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
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 v1.20.0 master-1 Ready master 73m v1.20.0 master-2 Ready master 74m v1.20.0 worker-0 Ready worker 11m v1.20.0 worker-1 Ready worker 11m v1.20.0
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.
7.2.11. 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 4.5.4 True False False 69s cloud-credential 4.5.4 True False False 12m cluster-autoscaler 4.5.4 True False False 11m console 4.5.4 True False False 46s dns 4.5.4 True False False 11m image-registry 4.5.4 True False False 5m26s ingress 4.5.4 True False False 5m36s kube-apiserver 4.5.4 True False False 8m53s kube-controller-manager 4.5.4 True False False 7m24s kube-scheduler 4.5.4 True False False 12m machine-api 4.5.4 True False False 12m machine-config 4.5.4 True False False 7m36s marketplace 4.5.4 True False False 7m54m monitoring 4.5.4 True False False 7h54s network 4.5.4 True False False 5m9s node-tuning 4.5.4 True False False 11m openshift-apiserver 4.5.4 True False False 11m openshift-controller-manager 4.5.4 True False False 5m943s openshift-samples 4.5.4 True False False 3m55s operator-lifecycle-manager 4.5.4 True False False 11m operator-lifecycle-manager-catalog 4.5.4 True False False 11m service-ca 4.5.4 True False False 11m service-catalog-apiserver 4.5.4 True False False 5m26s service-catalog-controller-manager 4.5.4 True False False 5m25s storage 4.5.4 True False False 5m30s
- Configure the Operators that are not available.
7.2.11.1. 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.
7.2.11.1.1. Configuring registry storage for bare metal
As a cluster administrator, following installation you must configure your registry to use storage.
Prerequisites
- Cluster administrator permissions.
- A cluster on bare metal.
Persistent storage provisioned for your cluster, such as Red Hat OpenShift Container Storage.
ImportantOpenShift Container Platform supports
ReadWriteOnce
access for image registry storage when you have only one replica. 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 using 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
NoteIf the storage type is
emptyDIR
, the replica number cannot be greater than1
.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
7.2.11.1.2. 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.
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
7.2.12. 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 4.5.4 True False False 7m56s cloud-credential 4.5.4 True False False 31m cluster-autoscaler 4.5.4 True False False 16m console 4.5.4 True False False 10m csi-snapshot-controller 4.5.4 True False False 16m dns 4.5.4 True False False 22m etcd 4.5.4 False False False 25s image-registry 4.5.4 True False False 16m ingress 4.5.4 True False False 16m insights 4.5.4 True False False 17m kube-apiserver 4.5.4 True False False 19m kube-controller-manager 4.5.4 True False False 20m kube-scheduler 4.5.4 True False False 20m kube-storage-version-migrator 4.5.4 True False False 16m machine-api 4.5.4 True False False 22m machine-config 4.5.4 True False False 22m marketplace 4.5.4 True False False 16m monitoring 4.5.4 True False False 10m network 4.5.4 True False False 23m node-tuning 4.5.4 True False False 23m openshift-apiserver 4.5.4 True False False 17m openshift-controller-manager 4.5.4 True False False 15m openshift-samples 4.5.4 True False False 16m operator-lifecycle-manager 4.5.4 True False False 22m operator-lifecycle-manager-catalog 4.5.4 True False False 22m operator-lifecycle-manager-packageserver 4.5.4 True False False 18m service-ca 4.5.4 True False False 23m service-catalog-apiserver 4.5.4 True False False 23m service-catalog-controller-manager 4.5.4 True False False 23m storage 4.5.4 True False False 17m
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.
ImportantThe 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.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.
Next steps
- Customize your cluster.
- 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.