Chapter 1. Installing on bare metal

1.1. Installing a cluster on bare metal

In OpenShift Container Platform version 4.6, you can install a cluster on bare metal infrastructure that you provision.

Important

While you might be able to follow this procedure to deploy a cluster on virtualized or cloud environments, you must be aware of additional considerations for non-bare metal platforms. Review the information in the guidelines for deploying OpenShift Container Platform on non-tested platforms before you attempt to install an OpenShift Container Platform cluster in such an environment.

1.1.1. Prerequisites

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.
Note
Be sure to also review this site list if you are configuring a proxy.

1.1.2. Internet access for OpenShift Container Platform

In OpenShift Container Platform 4.6, you require access to the Internet to install your cluster.

You must have Internet access to:

Access OpenShift Cluster Manager 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.

Important

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.

1.1.3. 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.

1.1.3.1. 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. If you are running a three-node cluster, running zero compute machines is supported. Running one compute machine is not supported.

Note

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.

Important

To maintain high availability of your cluster, use separate physical hosts for these cluster machines.

The bootstrap and control plane machines must use Red Hat Enterprise Linux CoreOS (RHCOS) as the operating system. However, the compute machines can choose between Red Hat Enterprise Linux CoreOS (RHCOS) or Red Hat Enterprise Linux (RHEL) 7.9.

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.

1.1.3.2. 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.

1.1.3.3. Minimum resource requirements

Each cluster machine must meet the following minimum requirements:

Machine	Operating System	CPU ^[1]	RAM	Storage	IOPS ^[2]
Bootstrap	RHCOS	4	16 GB	100 GB	300
Control plane	RHCOS	4	16 GB	100 GB	300
Compute	RHCOS or RHEL 7.9	2	8 GB	100 GB	300

One CPU is equivalent to one 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 = CPUs.
OpenShift Container Platform and Kubernetes are sensitive to disk performance, and faster storage is recommended, particularly for etcd on the control plane nodes which require a 10 ms p99 fsync duration. Note that on many cloud platforms, storage size and IOPS scale together, so you might need to over-allocate storage volume to obtain sufficient performance.

1.1.3.4. 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.

1.1.4. 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.

1.1.4.1. 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.

During the initial boot, the machines require either a DHCP server or that static IP addresses be set on each host in the cluster in order to establish a network connection, which allows them to download their Ignition config files.

It is recommended to use the DHCP server to manage the machines for the cluster long-term. Ensure that the DHCP server is configured to provide persistent IP addresses and host names to the cluster machines.

The Kubernetes API server must be able to resolve the node names of the cluster machines. If the API servers and worker nodes are in different zones, you can configure a default DNS search zone to allow the API server to resolve the node names. Another supported approach is to always refer to hosts by their fully-qualified domain names in both the node objects and all DNS requests.

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.

Table 1.1. All machines to all machines
Protocol	Port	Description
ICMP	N/A	Network reachability tests
TCP	`1936`	Metrics
	`9000`-`9999`	Host level services, including the node exporter on ports `9100`-`9101` and the Cluster Version Operator on port `9099`.
	`10250`-`10259`	The default ports that Kubernetes reserves
	`10256`	openshift-sdn
UDP	`4789`	VXLAN and Geneve
	`6081`	VXLAN and Geneve
	`9000`-`9999`	Host level services, including the node exporter on ports `9100`-`9101`.
TCP/UDP	`30000`-`32767`	Kubernetes node port

Table 1.2. All machines to control plane
Protocol	Port	Description
TCP	`6443`	Kubernetes API

Table 1.3. Control plane machines to control plane machines
Protocol	Port	Description
TCP	`2379`-`2380`	etcd server and peer ports

Network topology requirements

The infrastructure that you provision for your cluster must meet the following network topology requirements.

Important

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.

Important

Do not configure session persistence for an API load balancer.

Configure the following ports on both the front and back of the load balancers:

Table 1.4. 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

Note

The 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 1.5. 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

Tip

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.

Note

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.

NTP configuration

OpenShift Container Platform clusters are configured to use a public Network Time Protocol (NTP) server by default. If you want to use a local enterprise NTP server, or if your cluster is being deployed in a disconnected network, you can configure the cluster to use a specific time server. For more information, see the documentation for Configuring chrony time service.

If a DHCP server provides NTP server information, the chrony time service on the Red Hat Enterprise Linux CoreOS (RHCOS) machines read the information and can sync the clock with the NTP servers.

Additional resources

Configuring chrony time service

1.1.4.2. 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>..

Table 1.6. Required DNS records
Component	Record	Description
Kubernetes API	`api.<cluster_name>.<base_domain>.`	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.
Kubernetes API	`api-int.<cluster_name>.<base_domain>.`	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	`*.apps.<cluster_name>.<base_domain>.`	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	`bootstrap.<cluster_name>.<base_domain>.`	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	`<master><n>.<cluster_name>.<base_domain>.`	DNS A/AAAA or CNAME records and DNS PTR records to identify each machine for the control plane nodes (also known as the master nodes). These records must be resolvable by the nodes within the cluster.
Worker hosts	`<worker><n>.<cluster_name>.<base_domain>.`	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.

Tip

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 1.1. 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 1.2. 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

1.1.5. 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.

Note

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.

Note

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.
Note
If 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 the ed25519 algorithm. Instead, create a key that uses the rsa or ecdsa algorithm.
Start the ssh-agent process as a background task:
```
$ eval "$(ssh-agent -s)"
```
Example output
```
Agent pid 31874
```
Note
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

Next steps

When you install OpenShift Container Platform, provide the SSH public key to the installation program. If you install a cluster on infrastructure that you provision, you must provide this key to your cluster’s machines.

1.1.6. Obtaining the installation program

Before you install OpenShift Container Platform, download the installation file on a local computer.

Prerequisites

You have a computer that runs Linux or macOS, with 500 MB of local disk space

Procedure

Access the Infrastructure Provider page on the OpenShift Cluster Manager site. If you have a Red Hat account, log in with your credentials. If you do not, create an account.
Select your infrastructure provider.
Navigate to the page for your installation type, download the installation program for your operating system, and place the file in the directory where you will store the installation configuration files.
Important
The installation program creates several files on the computer that you use to install your cluster. You must keep the installation program and the files that the installation program creates after you finish installing the cluster. Both files are required to delete the cluster.
Important
Deleting the files created by the installation program does not remove your cluster, even if the cluster failed during installation. To remove your cluster, complete the OpenShift Container Platform uninstallation procedures for your specific cloud provider.
Extract the installation program. For example, on a computer that uses a Linux operating system, run the following command:
```
$ tar xvf openshift-install-linux.tar.gz
```
Download your installation pull secret from the Red Hat OpenShift Cluster Manager. This pull secret allows you to authenticate with the services that are provided by the included authorities, including Quay.io, which serves the container images for OpenShift Container Platform components.

1.1.7. Installing the OpenShift 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.

Important

If you installed an earlier version of oc, you cannot use it to complete all of the commands in OpenShift Container Platform 4.6. Download and install the new version of oc.

1.1.7.1. Installing the OpenShift CLI on Linux

You can install the OpenShift CLI (oc) binary on Linux by using the following procedure.

Procedure

Navigate to the OpenShift Container Platform downloads page on the Red Hat Customer Portal.
Select the appropriate version in the Version drop-down menu.
Click Download Now next to the OpenShift v4.6 Linux Client entry and save the file.
Unpack the archive:
```
$ tar xvzf <file>
```
Place the oc binary in a directory that is on your PATH.
To check your PATH, execute the following command:
```
$ echo $PATH
```

After you install the OpenShift CLI, it is available using the oc command:

$ oc <command>

1.1.7.2. Installing the OpenShift CLI on Windows

You can install the OpenShift CLI (oc) binary on Windows by using the following procedure.

Procedure

Navigate to the OpenShift Container Platform downloads page on the Red Hat Customer Portal.
Select the appropriate version in the Version drop-down menu.
Click Download Now next to the OpenShift v4.6 Windows Client entry and save the file.
Unzip the archive with a ZIP program.
Move the oc binary to a directory that is on your PATH.
To check your PATH, open the command prompt and execute the following command:
```
C:\> path
```

After you install the OpenShift CLI, it is available using the oc command:

C:\> oc <command>

1.1.7.3. Installing the OpenShift CLI on macOS

You can install the OpenShift CLI (oc) binary on macOS by using the following procedure.

Procedure

Navigate to the OpenShift Container Platform downloads page on the Red Hat Customer Portal.
Select the appropriate version in the Version drop-down menu.
Click Download Now next to the OpenShift v4.6 MacOSX Client entry and save the file.
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 OpenShift CLI, it is available using the oc command:

$ oc <command>

1.1.8. 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>
```
Important
You 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>.
Note
You 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.
Important
The install-config.yaml file is consumed during the next step of the installation process. You must back it up now.

1.1.8.1. Installation configuration parameters

Before you deploy an OpenShift Container Platform cluster, you provide parameter values to describe your account on the cloud platform that hosts your cluster and optionally customize your cluster’s platform. When you create the install-config.yaml installation configuration file, you provide values for the required parameters through the command line. If you customize your cluster, you can modify the install-config.yaml file to provide more details about the platform.

Note

After installation, you cannot modify these parameters in the install-config.yaml file.

Important

The openshift-install command does not validate field names for parameters. If an incorrect name is specified, the related file or object is not created, and no error is reported. Ensure that the field names for any parameters that are specified are correct.

1.1.8.1.1. Required configuration parameters

Required installation configuration parameters are described in the following table:

Table 1.7. Required parameters
Parameter	Description	Values
`apiVersion`	The API version for the `install-config.yaml` content. The current version is `v1`. The installer may also support older API versions.	String
`baseDomain`	The base domain of your cloud provider. The base domain is used to create routes to your OpenShift Container Platform cluster components. The full DNS name for your cluster is a combination of the `baseDomain` and `metadata.name` parameter values that uses the `<metadata.name>.<baseDomain>` format.	A fully-qualified domain or subdomain name, such as `example.com`.
`metadata`	Kubernetes resource `ObjectMeta`, from which only the `name` parameter is consumed.	Object
`metadata.name`	The name of the cluster. DNS records for the cluster are all subdomains of `{{.metadata.name}}.{{.baseDomain}}`.	String of lowercase letters, hyphens (`-`), and periods (`.`), such as `dev`.
`platform`	The configuration for the specific platform upon which to perform the installation: `aws`, `baremetal`, `azure`, `openstack`, `ovirt`, `vsphere`. For additional information about `platform.<platform>` parameters, consult the following table for your specific platform.	Object
`pullSecret`	Get a pull secret from the Red Hat OpenShift Cluster Manager to authenticate downloading container images for OpenShift Container Platform components from services such as Quay.io.	{ "auths":{ "cloud.openshift.com":{ "auth":"b3Blb=", "email":"you@example.com" }, "quay.io":{ "auth":"b3Blb=", "email":"you@example.com" } } }

1.1.8.1.2. Network configuration parameters

You can customize your installation configuration based on the requirements of your existing network infrastructure. For example, you can expand the IP address block for the cluster network or provide different IP address blocks than the defaults.

Only IPv4 addresses are supported.

Table 1.8. Network parameters
Parameter	Description	Values
`networking`	The configuration for the cluster network.	Object Note You cannot modify parameters specified by the `networking` object after installation.
`networking.networkType`	The cluster network provider Container Network Interface (CNI) plug-in to install.	Either `OpenShiftSDN` or `OVNKubernetes`. The default value is `OpenShiftSDN`.
`networking.clusterNetwork`	The IP address blocks for pods. The default value is `10.128.0.0/14` with a host prefix of `/23`. If you specify multiple IP address blocks, the blocks must not overlap.	An array of objects. For example: networking: clusterNetwork: - cidr: 10.128.0.0/14 hostPrefix: 23
`networking.clusterNetwork.cidr`	Required if you use `networking.clusterNetwork`. An IP address block. An IPv4 network.	An IP address block in Classless Inter-Domain Routing (CIDR) notation. The prefix length for an IPv4 block is between `0` and `32`.
`networking.clusterNetwork.hostPrefix`	The subnet prefix length to assign to each individual node. For example, if `hostPrefix` is set to `23` then each node is assigned a `/23` subnet out of the given `cidr`. A `hostPrefix` value of `23` provides 510 (2^(32 - 23) - 2) pod IP addresses.	A subnet prefix. The default value is `23`.
`networking.serviceNetwork`	The IP address block for services. The default value is `172.30.0.0/16`. The OpenShift SDN and OVN-Kubernetes network providers support only a single IP address block for the service network.	An array with an IP address block in CIDR format. For example: networking: serviceNetwork: - 172.30.0.0/16
`networking.machineNetwork`	The IP address blocks for machines. If you specify multiple IP address blocks, the blocks must not overlap.	An array of objects. For example: networking: machineNetwork: - cidr: 10.0.0.0/16
`networking.machineNetwork.cidr`	Required if you use `networking.machineNetwork`. An IP address block. The default value is `10.0.0.0/16` for all platforms other than libvirt. For libvirt, the default value is `192.168.126.0/24`.	An IP network block in CIDR notation. For example, `10.0.0.0/16`. Note Set the `networking.machineNetwork` to match the CIDR that the preferred NIC resides in.

1.1.8.1.3. Optional configuration parameters

Optional installation configuration parameters are described in the following table:

Table 1.9. Optional parameters
Parameter	Description	Values
`additionalTrustBundle`	A PEM-encoded X.509 certificate bundle that is added to the nodes' trusted certificate store. This trust bundle may also be used when a proxy has been configured.	String
`compute`	The configuration for the machines that comprise the compute nodes.	Array of machine-pool objects. For details, see the following "Machine-pool" table.
`compute.architecture`	Determines the instruction set architecture of the machines in the pool. Currently, heteregeneous clusters are not supported, so all pools must specify the same architecture. Valid values are `amd64` (the default).	String
`compute.hyperthreading`	Whether to enable or disable simultaneous multithreading, or `hyperthreading`, on compute machines. By default, simultaneous multithreading is enabled to increase the performance of your machines' cores. Important If you disable simultaneous multithreading, ensure that your capacity planning accounts for the dramatically decreased machine performance.	`Enabled` or `Disabled`
`compute.name`	Required if you use `compute`. The name of the machine pool.	`worker`
`compute.platform`	Required if you use `compute`. Use this parameter to specify the cloud provider to host the worker machines. This parameter value must match the `controlPlane.platform` parameter value.	`aws`, `azure`, `gcp`, `openstack`, `ovirt`, `vsphere`, or `{}`
`compute.replicas`	The number of compute machines, which are also known as worker machines, to provision.	A positive integer greater than or equal to `2`. The default value is `3`.
`controlPlane`	The configuration for the machines that comprise the control plane.	Array of `MachinePool` objects. For details, see the following "Machine-pool" table.
`controlPlane.architecture`	Determines the instruction set architecture of the machines in the pool. Currently, heterogeneous clusters are not supported, so all pools must specify the same architecture. Valid values are `amd64` (the default).	String
`controlPlane.hyperthreading`	Whether to enable or disable simultaneous multithreading, or `hyperthreading`, on control plane machines. By default, simultaneous multithreading is enabled to increase the performance of your machines' cores. Important If you disable simultaneous multithreading, ensure that your capacity planning accounts for the dramatically decreased machine performance.	`Enabled` or `Disabled`
`controlPlane.name`	Required if you use `controlPlane`. The name of the machine pool.	`master`
`controlPlane.platform`	Required if you use `controlPlane`. Use this parameter to specify the cloud provider that hosts the control plane machines. This parameter value must match the `compute.platform` parameter value.	`aws`, `azure`, `gcp`, `openstack`, `ovirt`, `vsphere`, or `{}`
`controlPlane.replicas`	The number of control plane machines to provision.	The only supported value is `3`, which is the default value.
`credentialsMode`	The Cloud Credential Operator (CCO) mode. If no mode is specified, the CCO dynamically tries to determine the capabilities of the provided credentials, with a preference for mint mode on the platforms where multiple modes are supported. Note Not all CCO modes are supported for all cloud providers. For more information on CCO modes, see the Cloud Credential Operator entry in the Red Hat Operators reference content.	`Mint`, `Passthrough`, `Manual`, or an empty string (`""`).
`fips`	Enable or disable FIPS mode. The default is `false` (disabled). 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. Important The use of FIPS Validated / Modules in Process cryptographic libraries is only supported on OpenShift Container Platform deployments on the `x86_64` architecture. Note If you are using Azure File storage, you cannot enable FIPS mode.	`false` or `true`
`imageContentSources`	Sources and repositories for the release-image content.	Array of objects. Includes a `source` and, optionally, `mirrors`, as described in the following rows of this table.
`imageContentSources.source`	Required if you use `imageContentSources`. Specify the repository that users refer to, for example, in image pull specifications.	String
`imageContentSources.mirrors`	Specify one or more repositories that may also contain the same images.	Array of strings
`publish`	How to publish or expose the user-facing endpoints of your cluster, such as the Kubernetes API, OpenShift routes.	`Internal` or `External`. The default value is `External`. Setting this field to `Internal` is not supported on non-cloud platforms. Important If the value of the field is set to `Internal`, the cluster will become non-functional. For more information, refer to BZ#1953035.
`sshKey`	The SSH key or keys to authenticate access your cluster machines. Note For production OpenShift Container Platform clusters on which you want to perform installation debugging or disaster recovery, specify an SSH key that your `ssh-agent` process uses.	One or more keys. For example: sshKey: <key1> <key2> <key3>

1.1.8.2. Sample install-config.yaml file for bare metal

You can customize the install-config.yaml file to specify more details about your OpenShift Container Platform cluster’s platform or modify the values of the required parameters.

apiVersion: v1
baseDomain: example.com 1
compute: 2
- hyperthreading: Enabled 3
  name: worker
  replicas: 0 4
controlPlane: 5
  hyperthreading: Enabled 6
  name: master
  replicas: 3 7
metadata:
  name: test 8
networking:
  clusterNetwork:
  - cidr: 10.128.0.0/14 9
    hostPrefix: 23 10
  networkType: 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 the compute section is a sequence of mappings. To meet the requirements of the different data structures, the first line of the compute section must begin with a hyphen, -, and the first line of the controlPlane section must not. 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 to Disabled. If you disable SMT, you must disable it in all cluster machines; this includes both control plane and compute machines.
Note
Simultaneous multithreading (SMT) is enabled by default. If SMT is not enabled in your BIOS settings, the hyperthreading parameter has no effect.
Important
If you disable hyperthreading, whether in the BIOS or in the install-config.yaml, ensure that your capacity planning accounts for the dramatically decreased machine performance.
4: You must set the value of the replicas parameter to 0. 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.
Note
Class E CIDR range is reserved for a future use. To use the Class E CIDR range, you must ensure your networking environment accepts the IP addresses within the Class E CIDR range.
10: The subnet prefix length to assign to each individual node. For example, if hostPrefix is set to 23, then each node is assigned a /23 subnet out of the given cidr, 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. This block must not overlap with existing physical networks. If you need to access the services from an external network, configure load balancers and routers to manage the traffic.
12: You must set the platform to none. You cannot provide additional platform configuration variables for your platform.
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.
Important
The use of FIPS Validated / Modules in Process cryptographic libraries is only supported on OpenShift Container Platform deployments on the x86_64 architecture.
14: The pull secret from the Red Hat OpenShift Cluster Manager. This pull secret allows you to authenticate with the services that are provided by the included authorities, including Quay.io, which serves the container images for OpenShift Container Platform components.
15: The public portion of the default SSH key for the core user in Red Hat Enterprise Linux CoreOS (RHCOS).
Note
For 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.

1.1.8.3. Configuring the cluster-wide proxy during installation

Production environments can deny direct access to the Internet and instead have an HTTP or HTTPS proxy available. You can configure a new OpenShift Container Platform cluster to use a proxy by configuring the proxy settings in the install-config.yaml file.

Note

For bare metal installations, if you do not assign node IP addresses from the range that is specified in the networking.machineNetwork[].cidr field in the install-config.yaml file, you must include them in the proxy.noProxy field.

Prerequisites

You have an existing install-config.yaml file.
You reviewed the sites that your cluster requires access to and determined whether any of them need to bypass the proxy. By default, all cluster egress traffic is proxied, including calls to hosting cloud provider APIs. You added sites to the Proxy object’s spec.noProxy field to bypass the proxy if necessary.
Note
The Proxy object status.noProxy field is populated with the values of the networking.machineNetwork[].cidr, networking.clusterNetwork[].cidr, and networking.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 object status.noProxy field is also populated with the instance metadata endpoint (169.254.169.254).

Procedure

Edit your install-config.yaml file and add the proxy settings. For example:
```
apiVersion: v1
baseDomain: my.domain.com
proxy:
  httpProxy: http://<username>:<pswd>@<ip>:<port> 1
  httpsProxy: https://<username>:<pswd>@<ip>:<port> 2
  noProxy: example.com 3
additionalTrustBundle: | 4
    -----BEGIN CERTIFICATE-----
    <MY_TRUSTED_CA_CERT>
    -----END CERTIFICATE-----
...
```
1
A proxy URL to use for creating HTTP connections outside the cluster. The URL scheme must be http.
2
A proxy URL to use for creating HTTPS connections outside the cluster.
3
A comma-separated list of destination domain names, IP addresses, or other network CIDRs to exclude from proxying. Preface a domain with . to match subdomains only. For example, .y.com matches x.y.com, but not y.com. Use * to bypass the proxy for all destinations.
4
If provided, the installation program generates a config map that is named user-ca-bundle in the openshift-config namespace to hold the additional CA certificates. If you provide additionalTrustBundle and at least one proxy setting, the Proxy object is configured to reference the user-ca-bundle config map in the trustedCA field. The Cluster Network Operator then creates a trusted-ca-bundle config map that merges the contents specified for the trustedCA parameter with the RHCOS trust bundle. The additionalTrustBundle field is required unless the proxy’s identity certificate is signed by an authority from the RHCOS trust bundle.
Note
The 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.

Note

Only the Proxy object named cluster is supported, and no additional proxies can be created.

1.1.9. Configuring a three-node cluster

You can optionally install and run three-node clusters in OpenShift Container Platform with no workers. This provides smaller, more resource efficient clusters for cluster administrators and developers to use for development, production, and testing.

Procedure

Edit the install-config.yaml file to set the number of compute replicas, which are also known as worker replicas, to 0, as shown in the following compute stanza:
```
compute:
- name: worker
  platform: {}
  replicas: 0
```

1.1.10. Creating the Kubernetes manifest and Ignition config files

Because you must modify some cluster definition files and manually start the cluster machines, you must generate the Kubernetes manifest and Ignition config files that the cluster needs to make its machines.

The installation configuration file transforms into the Kubernetes manifests. The manifests wrap into the Ignition configuration files, which are later used to create the cluster.

Important

The Ignition config files that the installation program generates contain certificates that expire after 24 hours, which are then renewed at that time. If the cluster is shut down before renewing the certificates and the cluster is later restarted after the 24 hours have elapsed, the cluster automatically recovers the expired certificates. The exception is that you must manually approve the pending node-bootstrapper certificate signing requests (CSRs) to recover kubelet certificates. See the documentation for Recovering from expired control plane certificates for more information.
It is recommended that you use Ignition config files within 12 hours after they are generated because the 24-hour certificate rotates from 16 to 22 hours after the cluster is installed. By using the Ignition config files within 12 hours, you can avoid installation failure if the certificate update runs during installation.

Prerequisites

You obtained the OpenShift Container Platform installation program.
You created the install-config.yaml installation configuration file.

Procedure

Change to the directory that contains the installation program and generate the Kubernetes manifests for the cluster:
```
$ ./openshift-install create manifests --dir <installation_directory> 1
```
1
For <installation_directory>, specify the installation directory that contains the install-config.yaml file you created.

Warning

If you are installing a three-node cluster, skip the following step to allow the control plane nodes to be schedulable.

Important

When you configure control plane nodes from the default unschedulable to schedulable, additional subscriptions are required. This is because control plane nodes then become worker nodes.

Check that the mastersSchedulable parameter in the <installation_directory>/manifests/cluster-scheduler-02-config.yml Kubernetes manifest file is set to false. This setting prevents pods from being scheduled on the control plane machines:
1. Open the <installation_directory>/manifests/cluster-scheduler-02-config.yml file.
2. Locate the mastersSchedulable parameter and ensure that it is set to false.
3. Save and exit the file.
To create the Ignition configuration files, run the following command from the directory that contains the installation program:
```
$ ./openshift-install create ignition-configs --dir <installation_directory> 1
```
1
For <installation_directory>, specify the same installation directory.
The following files are generated in the directory:
```
.
├── auth
│   ├── kubeadmin-password
│   └── kubeconfig
├── bootstrap.ign
├── master.ign
├── metadata.json
└── worker.ign
```

Additional resources

See Recovering from expired control plane certificates for more information about recovering kubelet certificates.

1.1.11. Installing RHCOS and starting the OpenShift Container Platform bootstrap process

To install OpenShift Container Platform on bare metal infrastructure that you provision, you must install Red Hat Enterprise Linux CoreOS (RHCOS) on the machines. When you install RHCOS, you must provide the Ignition config file that was generated by the OpenShift Container Platform installation program for the type of machine you are installing. If you have configured suitable networking, DNS, and load balancing infrastructure, the OpenShift Container Platform bootstrap process begins automatically after the RHCOS machines have rebooted.

To install RHCOS on the machines, follow either the steps to use an ISO image or network PXE booting.

Note

The compute node deployment steps included in this installation document are RHCOS-specific. If you choose instead to deploy RHEL-based compute nodes, you take responsibility for all operating system life cycle management and maintenance, including performing system updates, applying patches, and completing all other required tasks. Use of RHEL 7 compute machines is deprecated and planned for removal in a future release of OpenShift Container Platform 4.

You can configure RHCOS during ISO and PXE installations by using the following methods:

Kernel arguments: You can use kernel arguments to provide installation-specific information. For example, you can specify the locations of the RHCOS installation files that you uploaded to your HTTP server and the location of the Ignition config file for the type of node you are installing. For a PXE installation, you can use the APPEND parameter to pass the arguments to the kernel of the live installer. For an ISO installation, you can interrupt the live installation boot process to add the kernel arguments. In both installation cases, you can use special coreos.inst.* arguments to direct the live installer, as well as standard installation boot arguments for turning standard kernel services on or off.
Ignition configs: OpenShift Container Platform Ignition config files (*.ign) are specific to the type of node you are installing. You pass the location of a bootstrap, control plane, or compute node Ignition config file during the RHCOS installation so that it takes effect on first boot. In special cases, you can create a separate, limited Ignition config to pass to the live system. That Ignition config could do a certain set of tasks, such as reporting success to a provisioning system after completing installation. This special Ignition config is consumed by the coreos-installer to be applied on first boot of the installed system. Do not provide the standard control plane and compute node Ignition configs to the live ISO directly.
coreos-installer: You can boot the live ISO installer to a shell prompt, which allows you to prepare the permanent system in a variety of ways before first boot. In particular, you can run the coreos-installer command to identify various artifacts to include, work with disk partitions, and set up networking. In some cases, you can configure features on the live system and copy them to the installed system.

Whether to use an ISO or PXE install depends on your situation. A PXE install requires an available DHCP service and more preparation, but can make the installation process more automated. An ISO install is a more manual process and can be inconvenient if you are setting up more than a few machines.

Note

As of OpenShift Container Platform 4.6, the RHCOS ISO and other installation artifacts provide support for installation on disks with 4K sectors.

1.1.11.1. Creating Red Hat Enterprise Linux CoreOS (RHCOS) machines using an ISO image

Before you install a cluster on 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 can be accessed from your computer, and from the machines that you create.

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.
Important
If 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.
Important
The RHCOS images might not change with every release of OpenShift Container Platform. You must download images with the highest version that is less than or equal to the OpenShift Container Platform version that you install. Use the image versions that match your OpenShift Container Platform version if they are available. Use only ISO images for this procedure. RHCOS qcow2 images are not supported for this installation type.
ISO file names resemble the following example:
rhcos-<version>-live.<architecture>.iso
Use the ISO to start the RHCOS installation. Use one of the following installation options:
- Burn the ISO image to a disk and boot it directly.
- Use ISO redirection via a LOM interface.
Boot the ISO image. You can interrupt the installation boot process to add kernel arguments. However, for this ISO procedure you should use the coreos-installer command instead of adding kernel arguments. If you run the live installer without options or interruption, the installer boots up to a shell prompt on the live system, ready for you to install RHCOS to disk.
Review the Advanced RHCOS installation reference section for different ways of configuring features, such as networking and disk partitions, before running the coreos-installer.
Run the coreos-installer command. At a minimum, you must identify the Ignition config file location for your node type, and the location of the disk you are installing to. Here is an example:
```
$ sudo coreos-installer install \
     --ignition-url=https://host/worker.ign /dev/sda
```
After RHCOS installs, the system reboots. During the system reboot, it applies the Ignition config file that you specified.
Continue to create the other machines for your cluster.
Important
You 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.

1.1.11.2. Creating Red Hat Enterprise Linux CoreOS (RHCOS) machines by PXE or iPXE booting

Before you install a cluster that uses manually-provisioned RHCOS nodes, such as bare metal, you must create RHCOS machines for it to use. You can use PXE or iPXE booting to create the machines.

Prerequisites

Obtain the Ignition config files for your cluster.
Configure suitable PXE or iPXE infrastructure.
Have access to an HTTP 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.
Important
You can add or change configuration settings in your Ignition configs before saving them to your HTTP server. If you plan to add more compute machines to your cluster after you finish installation, do not delete these files.
Obtain the RHCOS kernel, initramfs and rootfs files from the RHCOS image mirror page.
Important
The RHCOS artifacts might not change with every release of OpenShift Container Platform. You must download artifacts with the highest version that is less than or equal to the OpenShift Container Platform version that you install. Only use the appropriate kernel, initramfs, and rootfs artifacts described below for this procedure. RHCOS qcow2 images are not supported for this installation type.
The file names contain the OpenShift Container Platform version number. They resemble the following examples:
- kernel: rhcos-<version>-live-kernel-<architecture>
- initramfs: rhcos-<version>-live-initramfs.<architecture>.img
- rootfs: rhcos-<version>-live-rootfs.<architecture>.img
Upload the additional files that are required for your booting method:
- For traditional PXE, upload the kernel and initramfs files to your TFTP server and the rootfs file to your HTTP server.
- For iPXE, upload the kernel, initramfs, and rootfs files to your HTTP server.
  Important
  If you plan to add more compute machines to your cluster after you finish installation, do not delete these files.
Configure the network boot infrastructure so that the machines boot from their local disks after RHCOS is installed on them.
Configure PXE or iPXE installation for the RHCOS images.
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 http://<HTTP_server>/rhcos-<version>-live-kernel-<architecture> 1
    APPEND initrd=http://<HTTP_server>/rhcos-<version>-live-initramfs.<architecture>.img coreos.live.rootfs_url=http://<HTTP_server>/rhcos-<version>-live-rootfs.<architecture>.img coreos.inst.install_dev=/dev/sda coreos.inst.ignition_url=http://<HTTP_server>/bootstrap.ign 2 3
```
  1
  Specify the location of the live kernel file that you uploaded to your HTTP server. The URL must be HTTP, TFTP, or FTP; HTTPS and NFS are not supported.
  2
  If you use multiple NICs, specify a single interface in the ip option. For example, to use DHCP on a NIC that is named eno1, set ip=eno1:dhcp.
  3
  Specify locations of the RHCOS files that you uploaded to your HTTP server. The initrd parameter value is the location of the initramfs file, the coreos.live.rootfs_url parameter value is the location of the rootfs file, and the coreos.inst.ignition_url parameter value is the location of the bootstrap Ignition config file. You can also add more kernel arguments to the APPEND line to configure networking or other boot options.
  Note
  This 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 the APPEND line. For example, add console=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?.
- For iPXE:
```
kernel http://<HTTP_server>/rhcos-<version>-live-kernel-<architecture> initrd=main coreos.live.rootfs_url=http://<HTTP_server>/rhcos-<version>-live-rootfs.<architecture>.img coreos.inst.install_dev=/dev/sda coreos.inst.ignition_url=http://<HTTP_server>/bootstrap.ign 1 2
initrd --name main http://<HTTP_server>/rhcos-<version>-live-initramfs.<architecture>.img 3
boot
```
  1
  Specify locations of the RHCOS files that you uploaded to your HTTP server. The kernel parameter value is the location of the kernel file, the initrd=main argument is needed for booting on UEFI systems, the coreos.live.rootfs_url parameter value is the location of the rootfs file, and the coreos.inst.ignition_url parameter value is the location of the bootstrap Ignition config file.
  2
  If you use multiple NICs, specify a single interface in the ip option. For example, to use DHCP on a NIC that is named eno1, set ip=eno1:dhcp.
  3
  Specify the location of the initramfs file that you uploaded to your HTTP server.
  Note
  This 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 the kernel line. For example, add console=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 PXE UEFI, perform the following actions:
1. Provide the shimx64.efi and grubx64.efi EFI binaries and the grub.cfg file that are required for booting the system.
  - Extract the necessary EFI binaries by mounting the RHCOS ISO to your host and then mounting the images/efiboot.img file to your host:
    $ mkdir -p /mnt/iso
    $ mkdir -p /mnt/efiboot
    $ mount -o loop rhcos-installer.x86_64.iso /mnt/iso
    $ mount -o loop,ro /mnt/iso/images/efiboot.img /mnt/efiboot
  - From the efiboot.img mount point, copy the EFI/redhat/shimx64.efi and EFI/redhat/grubx64.efi files to your TFTP server:
    $ cp /mnt/efiboot/EFI/redhat/shimx64.efi .
    $ cp /mnt/efiboot/EFI/redhat/grubx64.efi .
    $ umount /mnt/efiboot
    $ umount /mnt/iso
  - Copy the EFI/redhat/grub.cfg file that is included in the RHCOS ISO to your TFTP server.
2. Edit the grub.cfg file to include arguments similar to the following:
```
menuentry 'Install Red Hat Enterprise Linux CoreOS' --class fedora --class gnu-linux --class gnu --class os {
	linuxefi rhcos-<version>-live-kernel-<architecture> coreos.inst.install_dev=/dev/sda coreos.live.rootfs_url=http://<HTTP_server>/rhcos-<version>-live-rootfs.<architecture>.img coreos.inst.ignition_url=http://<HTTP_server>/bootstrap.ign
	initrdefi rhcos-<version>-live-initramfs.<architecture>.img
}
```
  where:
  rhcos-<version>-live-kernel-<architecture>
  Specifies the kernel file that you uploaded to your TFTP server.
  http://<HTTP_server>/rhcos-<version>-live-rootfs.<architecture>.img
  Specifies the location of the live rootfs image that you uploaded to your HTTP server.
  http://<HTTP_server>/bootstrap.ign
  Specifies the location of the bootstrap Ignition config file that you uploaded to your HTTP server.
  rhcos-<version>-live-initramfs.<architecture>.img
  Specifies the location of the initramfs file that you uploaded to your TFTP server.
  Note
  For more information on how to configure a PXE server for UEFI boot, see the Red Hat Knowledgebase article: How to configure/setup a PXE server for UEFI boot for Red Hat Enterprise Linux?.
Continue to create the machines for your cluster.
Important
You 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.

1.1.11.3. Advanced Red Hat Enterprise Linux CoreOS (RHCOS) installation configuration

A key benefit for manually provisioning the Red Hat Enterprise Linux CoreOS (RHCOS) nodes for OpenShift Container Platform is to be able to do configuration that is not available through default OpenShift Container Platform installation methods. This section describes some of the configurations that you can do using techniques that include:

Passing kernel arguments to the live installer
Running coreos-installer manually from the live system
Embedding Ignition configs in an ISO

The advanced configuration topics for manual Red Hat Enterprise Linux CoreOS (RHCOS) installations detailed in this section relate to disk partitioning, networking, and using Ignition configs in different ways.

1.1.11.3.1. Using advanced networking options for PXE and ISO installations

Networking for OpenShift Container Platform nodes uses DHCP by default to gather all necessary configuration settings. To set up static IP addresses or configure special settings, such as bonding, you can do one of the following:

Pass special kernel parameters when you boot the live installer.
Use a machine config to copy networking files to the installed system.
Configure networking from a live installer shell prompt, then copy those settings to the installed system so that they take effect when the installed system first boots.

To configure a PXE or iPXE installation, use one of the following options:

See the "Advanced RHCOS installation reference" tables.
Use a machine config to copy networking files to the installed system.

To configure an ISO installation, use the following procedure.

Procedure

Boot the ISO installer.
From the live system shell prompt, configure networking for the live system using available RHEL tools, such as nmcli or nmtui.
Run the coreos-installer command to install the system, adding the --copy-network option to copy networking configuration. For example:
```
$ coreos-installer install --copy-network \
     --ignition-url=http://host/worker.ign /dev/sda
```
Important
The --copy-network option only copies networking configuration found under /etc/NetworkManager/system-connections. In particular, it does not copy the system hostname.
Reboot into the installed system.

1.1.11.3.2. Disk partitioning

The disk partitions are created on OpenShift Container Platform cluster nodes during the Red Hat Enterprise Linux CoreOS (RHCOS) installation. Each RHCOS node of a particular architecture uses the same partition layout, unless the default partitioning configuration is overridden. During the RHCOS installation, the size of the root file system is increased to use the remaining available space on the target device.

However, there are two cases where you might want to intervene to override the default partitioning when installing an OpenShift Container Platform node:

Create separate partitions: For greenfield installations on an empty disk, you might want to add separate storage to a partition. This is officially supported for making /var or a subdirectory of /var, such as /var/lib/etcd, a separate partition, but not both.
Important
Kubernetes supports only two filesystem partitions. If you add more than one partition to the original configuration, Kubernetes cannot monitor all of them.
Retain existing partitions: For a brownfield installation where you are reinstalling OpenShift Container Platform on an existing node and want to retain data partitions installed from your previous operating system, there are both boot arguments and options to coreos-installer that allow you to retain existing data partitions.

1.1.11.3.2.1. Creating a separate `/var` partition

In general, disk partitioning for OpenShift Container Platform should be left to the installer. However, there are cases where you might want to create separate partitions in a part of the filesystem that you expect to grow.

OpenShift Container Platform supports the addition of a single partition to attach storage to either the /var partition or a subdirectory of /var. For example:

/var/lib/containers: Holds container-related content that can grow as more images and containers are added to a system.
/var/lib/etcd: Holds data that you might want to keep separate for purposes such as performance optimization of etcd storage.
/var: Holds data that you might want to keep separate for purposes such as auditing.

Storing the contents of a /var directory separately makes it easier to grow storage for those areas as needed and reinstall OpenShift Container Platform at a later date and keep that data intact. With this method, you will not have to pull all your containers again, nor will you have to copy massive log files when you update systems.

Because /var must be in place before a fresh installation of Red Hat Enterprise Linux CoreOS (RHCOS), the following procedure sets up the separate /var partition by creating a machine config that is inserted during the openshift-install preparation phases of an OpenShift Container Platform installation.

Procedure

Create a directory to hold the OpenShift Container Platform installation files:
```
$ mkdir $HOME/clusterconfig
```

Run openshift-install to create a set of files in the manifest and openshift subdirectories. Answer the system questions as you are prompted:

$ openshift-install create manifests --dir $HOME/clusterconfig
? SSH Public Key ...
$ ls $HOME/clusterconfig/openshift/
99_kubeadmin-password-secret.yaml
99_openshift-cluster-api_master-machines-0.yaml
99_openshift-cluster-api_master-machines-1.yaml
99_openshift-cluster-api_master-machines-2.yaml
...

Create a MachineConfig object and add it to a file in the openshift directory. For example, name the file 98-var-partition.yaml, change the disk device name to the name of the storage device on the worker systems, and set the storage size as appropriate. This example places the /var directory on a separate partition:
```
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
metadata:
  labels:
    machineconfiguration.openshift.io/role: worker
  name: 98-var-partition
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      disks:
      - device: /dev/<device_name> 1
        partitions:
        - label: var
          startMiB: <partition_start_offset> 2
          sizeMiB: <partition_size> 3
      filesystems:
        - device: /dev/disk/by-partlabel/var
          path: /var
          format: xfs
    systemd:
      units:
        - name: var.mount 4
          enabled: true
          contents: |
            [Unit]
            Before=local-fs.target
            [Mount]
            What=/dev/disk/by-partlabel/var
            Where=/var
            Options=defaults,prjquota 5
            [Install]
            WantedBy=local-fs.target
```
1
The storage device name of the disk that you want to partition.
2
When adding a data partition to the boot disk, a minimum value of 25000 mebibytes is recommended. The root file system is automatically resized to fill all available space up to the specified offset. If no value is specified, or if the specified value is smaller than the recommended minimum, the resulting root file system will be too small, and future reinstalls of RHCOS might overwrite the beginning of the data partition.
3
The size of the data partition in mebibytes.
4
The name of the mount unit must match the directory specified in the Where= directive. For example, for a filesystem mounted on /var/lib/containers, the unit must be named var-lib-containers.mount.
5
The prjquota mount option must be enabled for filesystems used for container storage.
Note
When creating a separate /var partition, you cannot use different instance types for worker nodes, if the different instance types do not have the same device name.

Run openshift-install again to create Ignition configs from a set of files in the manifest and openshift subdirectories:

$ openshift-install create ignition-configs --dir $HOME/clusterconfig
$ ls $HOME/clusterconfig/
auth  bootstrap.ign  master.ign  metadata.json  worker.ign

Now you can use the Ignition config files as input to the ISO or PXE manual installation procedures to install Red Hat Enterprise Linux CoreOS (RHCOS) systems.

1.1.11.3.2.2. Retaining existing partitions

For an ISO installation, you can add options to the coreos-installer command line that causes the installer to maintain one or more existing partitions. For a PXE installation, you can APPEND coreos.inst.* options to preserve partitions.

Saved partitions might be partitions from an existing OpenShift Container Platform system that has data partitions that you want to keep. Here are a few tips:

If you save existing partitions, and those partitions do not leave enough space for RHCOS, installation will fail without damaging the saved partitions.
Identify the disk partitions you want to keep either by partition label or by number.

For an ISO installation

This example preserves any partition in which the partition label begins with data (data*):

# coreos-installer install --ignition-url http://10.0.2.2:8080/user.ign \
        --save-partlabel 'data*' /dev/sda

The following example illustrates running the coreos-installer in a way that preserves the sixth (6) partition on the disk:

# coreos-installer install --ignition-url http://10.0.2.2:8080/user.ign \
        --save-partindex 6 /dev/sda

This example preserves partitions 5 and higher:

# coreos-installer install --ignition-url http://10.0.2.2:8080/user.ign
        --save-partindex 5- /dev/sda

In the previous examples where partition saving is used, coreos-installer recreates the partition immediately.

For a PXE installation

This APPEND option preserves any partition in which the partition label begins with 'data' ('data*'):

coreos.inst.save_partlabel=data*

This APPEND option preserves partitions 5 and higher:

coreos.inst.save_partindex=5-

This APPEND option preserves partition 6:

coreos.inst.save_partindex=6

1.1.11.3.3. Identifying Ignition configs

When doing an RHCOS manual installation, there are two types of Ignition configs that you can provide, with different reasons for providing each one:

Permanent install Ignition config: Every manual RHCOS installation needs to pass one of the Ignition config files generated by openshift-installer, such as bootstrap.ign, master.ign and worker.ign, to carry out the installation.
Important
It is not recommended to modify these files.
For PXE installations, you pass the Ignition configs on the APPEND line using the coreos.inst.ignition_url= option. For ISO installations, after the ISO boots to the shell prompt, you identify the Ignition config on the coreos-installer command line with the --ignition-url= option. In both cases, only HTTP and HTTPS protocols are supported.
Live install Ignition config: This type must be created manually and should be avoided if possible, as it is not supported by Red Hat. With this method, the Ignition config passes to the live install medium, runs immediately upon booting, and performs setup tasks before and/or after the RHCOS system installs to disk. This method should only be used for performing tasks that must be performed once and not applied again later, such as with advanced partitioning that cannot be done using a machine config.
For PXE or ISO boots, you can create the Ignition config and APPEND the ignition.config.url= option to identify the location of the Ignition config. You also need to append ignition.firstboot ignition.platform.id=metal or the ignition.config.url option will be ignored.

1.1.11.3.3.1. Embedding an Ignition config in the RHCOS ISO

You can embed a live install Ignition config directly in an RHCOS ISO image. When the ISO image is booted, the embedded config will be applied automatically.

Procedure

Download the coreos-installer binary from the following image mirror page: https://mirror.openshift.com/pub/openshift-v4/clients/coreos-installer/latest/.
Retrieve the RHCOS ISO image and the Ignition config file, and copy them into an accessible directory, such as /mnt:
```
# cp rhcos-<version>-live.x86_64.iso bootstrap.ign /mnt/
# chmod 644 /mnt/rhcos-<version>-live.x86_64.iso
```
Run the following command to embed the Ignition config into the ISO:
```
# ./coreos-installer iso ignition embed -i /mnt/bootstrap.ign \
     /mnt/rhcos-<version>-live.x86_64.iso
```
You can now use that ISO to install RHCOS using the specified live install Ignition config.
Important
Using coreos-installer iso ignition embed to embed a file generated by openshift-installer, such as bootstrap.ign, master.ign and worker.ign, is unsupported and not recommended.

To show the contents of the embedded Ignition config and direct it into a file, run:

# ./coreos-installer iso ignition show /mnt/rhcos-<version>-live.x86_64.iso > mybootstrap.ign

# diff -s bootstrap.ign mybootstrap.ign

Example output

Files bootstrap.ign and mybootstrap.ign are identical

To remove the Ignition config and return the ISO to its pristine state so you can reuse it, run:
```
# ./coreos-installer iso ignition remove /mnt/rhcos-<version>-live.x86_64.iso
```
You can now embed another Ignition config into the ISO or use the ISO in its pristine state.

1.1.11.3.4. Advanced RHCOS installation reference

This section illustrates the networking configuration and other advanced options that allow you to modify the Red Hat Enterprise Linux CoreOS (RHCOS) manual installation process. The following tables describe the kernel arguments and command-line options you can use with the RHCOS live installer and the coreos-installer command.

Routing and bonding options at RHCOS boot prompt

If you install RHCOS from an ISO image, you can add kernel arguments manually when you boot that image to configure the node’s networking. If no networking arguments are used, the installation defaults to using DHCP.

Important

When adding networking arguments, you must also add the rd.neednet=1 kernel argument.

The following table describes how to use ip=, nameserver=, and bond= kernel arguments for live ISO installs.

Note

Ordering is important when adding kernel arguments: ip=, nameserver=, and then bond=.

Routing and bonding options for ISO

The following table provides examples for configuring networking of your Red Hat Enterprise Linux CoreOS (RHCOS) nodes. These are networking options that are passed to the dracut tool during system boot. For more information about the networking options supported by dracut, see the dracut.cmdline manual page.

Description	Examples
To configure an IP address, either use DHCP (`ip=dhcp`) or set an individual static IP address (`ip=<host_ip>`). Then identify the DNS server IP address (`nameserver=<dns_ip>`) on each node. This example sets: The node’s IP address to `10.10.10.2` The gateway address to `10.10.10.254` The netmask to `255.255.255.0` The hostname to `core0.example.com` The DNS server address to `4.4.4.41`	ip=10.10.10.2::10.10.10.254:255.255.255.0:core0.example.com:enp1s0:none nameserver=4.4.4.41
Specify multiple network interfaces by specifying multiple `ip=` entries.	ip=10.10.10.2::10.10.10.254:255.255.255.0:core0.example.com:enp1s0:none ip=10.10.10.3::10.10.10.254:255.255.255.0:core0.example.com:enp2s0:none
Optional: You can configure routes to additional networks by setting an `rd.route=` value. If the additional network gateway is different from the primary network gateway, the default gateway must be the primary network gateway.	To configure the default gateway: ip=::10.10.10.254:::: To configure the route for the additional network: rd.route=20.20.20.0/24:20.20.20.254:enp2s0
Disable DHCP on a single interface, such as when there are two or more network interfaces and only one interface is being used.	ip=10.10.10.2::10.10.10.254:255.255.255.0:core0.example.com:enp1s0:none ip=::::core0.example.com:enp2s0:none
You can combine DHCP and static IP configurations on systems with multiple network interfaces.	ip=enp1s0:dhcp ip=10.10.10.2::10.10.10.254:255.255.255.0:core0.example.com:enp2s0:none
Optional: You can configure VLANs on individual interfaces by using the `vlan=` parameter.	To configure a VLAN on a network interface and use a static IP address: ip=10.10.10.2::10.10.10.254:255.255.255.0:core0.example.com:enp2s0.100:none vlan=enp2s0.100:enp2s0 To configure a VLAN on a network interface and to use DHCP: ip=enp2s0.100:dhcp vlan=enp2s0.100:enp2s0
You can provide multiple DNS servers by adding a `nameserver=` entry for each server.	nameserver=1.1.1.1 nameserver=8.8.8.8
Optional: Bonding multiple network interfaces to a single interface is supported using the `bond=` option. In these two examples: The syntax for configuring a bonded interface is: `bond=name[:network_interfaces][:options]` name is the bonding device name (`bond0`), network_interfaces represents a comma-separated list of physical (ethernet) interfaces (`em1,em2`), and options is a comma-separated list of bonding options. Enter `modinfo bonding` to see available options. When you create a bonded interface using `bond=`, you must specify how the IP address is assigned and other information for the bonded interface.	To configure the bonded interface to use DHCP, set the bond’s IP address to `dhcp`. For example: bond=bond0:em1,em2:mode=active-backup ip=bond0:dhcp To configure the bonded interface to use a static IP address, enter the specific IP address you want and related information. For example: bond=bond0:em1,em2:mode=active-backup ip=10.10.10.2::10.10.10.254:255.255.255.0:core0.example.com:bond0:none
Optional: You can configure VLANs on bonded interfaces by using the `vlan=` parameter.	To configure the bonded interface with a VLAN and to use DHCP: ip=bond0.100:dhcp bond=bond0:em1,em2:mode=active-backup vlan=bond0.100:bond0 To configure the bonded interface with a VLAN and to use a static IP address: ip=10.10.10.2::10.10.10.254:255.255.255.0:core0.example.com:bond0.100:none bond=bond0:em1,em2:mode=active-backup vlan=bond0.100:bond0
Optional: Network teaming can be used as an alternative to bonding by using the `team=` parameter. In this example: The syntax for configuring a team interface is: `team=name[:network_interfaces]` name is the team device name (`team0`) and network_interfaces represents a comma-separated list of physical (ethernet) interfaces (`em1, em2`). Note Teaming is planned to be deprecated when RHCOS switches to an upcoming version of RHEL. For more information, see this Red Hat Knowledgebase Article.	To configure a network team: team=team0:em1,em2 ip=team0:dhcp

`coreos.inst` boot options for ISO or PXE install

While you can pass most standard installation boot arguments to the live installer, there are several arguments that are specific to the RHCOS live installer.

For ISO, these options can be added by interrupting the RHCOS installer.
For PXE or iPXE, these options must be added to the APPEND line before starting the PXE kernel. You cannot interrupt a live PXE install.

The following table shows the RHCOS live installer boot options for ISO and PXE installs.

Table 1.10. coreos.inst boot options
Argument	Description
`coreos.inst.install_dev`	Required. The block device on the system to install to. It is recommended to use the full path, such as `/dev/sda`, although `sda` is allowed.
`coreos.inst.ignition_url`	Optional: The URL of the Ignition config to embed into the installed system. If no URL is specified, no Ignition config is embedded.
`coreos.inst.save_partlabel`	Optional: Comma-separated labels of partitions to preserve during the install. Glob-style wildcards are permitted. The specified partitions do not need to exist.
`coreos.inst.save_partindex`	Optional: Comma-separated indexes of partitions to preserve during the install. Ranges `m`-`n` are permitted, and either `m` or `n` can be omitted. The specified partitions do not need to exist.
`coreos.inst.insecure`	Optional: Permits the OS image that is specified by `coreos.inst.image_url` to be unsigned.
`coreos.inst.image_url`	Optional: Download and install the specified RHCOS image. This argument should not be used in production environments and is intended for debugging purposes only. While this argument can be used to install a version of RHCOS that does not match the live media, it is recommended that you instead use the media that matches the version you want to install. If you are using `coreos.inst.image_url`, you must also use `coreos.inst.insecure`. This is because the bare-metal media are not GPG-signed for OpenShift Container Platform. Only HTTP and HTTPS protocols are supported.
`coreos.inst.skip_reboot`	Optional: The system will not reboot after installing. Once the install finishes, you will receive a prompt that allows you to inspect what is happening during installation. This argument should not be used in production environments and is intended for debugging purposes only.
`coreos.inst.platform_id`	Optional: The Ignition platform ID of the platform the RHCOS image is being installed on. Default is `metal`. This option determines whether or not to request an Ignition config from the cloud provider, such as VMware. For example: `coreos.inst.platform_id=vmware`.
`ignition.config.url`	Optional: The URL of the Ignition config for the live boot. For example, this can be used to customize how `coreos-installer` is invoked, or to run code before or after the installation. This is different from `coreos.inst.ignition_url`, which is the Ignition config for the installed system.

`coreos-installer` options for ISO install

You can also install RHCOS by invoking the coreos-installer command directly from the command line. The kernel arguments in the previous table provide a shortcut for automatically invoking coreos-installer at boot time, but you can pass similar arguments directly to coreos-installer when running it from a shell prompt.

The following table shows the options and subcommands you can pass to the coreos-installer command from a shell prompt during a live install.

Table 1.11. coreos-installer command-line options, arguments, and subcommands
Command-line options
Option	Description
`-u`, `--image-url <url>`	Specify the image URL manually.
`-f`, `--image-file <path>`	Specify a local image file manually.
`-i,` `--ignition-file <path>`	Embed an Ignition config from a file.
`-I`, `--ignition-url <URL>`	Embed an Ignition config from a URL.
`--ignition-hash <digest>`	Digest `type-value` of the Ignition config.
`-p`, `--platform <name>`	Override the Ignition platform ID.
`--append-karg <arg>…`	Append the default kernel argument.
`--delete-karg <arg>…`	Delete the default kernel argument.
`-n`, `--copy-network`	Copy the network configuration from the install environment. Important The `--copy-network` option only copies networking configuration found under `/etc/NetworkManager/system-connections`. In particular, it does not copy the system hostname.
`--network-dir <path>`	For use with `-n`. Default is `/etc/NetworkManager/system-connections/`.
`--save-partlabel <lx>..`	Save partitions with this label glob.
`--save-partindex <id>…`	Save partitions with this number or range.
`--offline`	Force offline installation.
`--insecure`	Skip signature verification.
`--insecure-ignition`	Allow Ignition URL without HTTPS or hash.
`--architecture <name>`	Target CPU architecture. Default is `x86_64`.
`--preserve-on-error`	Do not clear partition table on error.
`-h`, `--help`	Print help information.
Command-line argument
Argument	Description
`<device>`	The destination device.
coreos-installer embedded Ignition commands
Command	Description
`$ coreos-installer iso ignition embed <options> --ignition-file <file_path> <ISO_image>`	Embed an Ignition config in an ISO image.
`coreos-installer iso ignition show <options> <ISO_image>`	Show the embedded Ignition config from an ISO image.
`coreos-installer iso ignition remove <options> <ISO_image>`	Remove the embedded Ignition config from an ISO image.
coreos-installer ISO Ignition options
Option	Description
`-f`, `--force`	Overwrite an existing Ignition config.
`-i`, `--ignition-file <path>`	The Ignition config to be used. Default is `stdin`.
`-o`, `--output <path>`	Write the ISO to a new output file.
`-h`, `--help`	Print help information.
coreos-installer PXE Ignition commands
Command	Description
Note that not all of these options are accepted by all subcommands.
`coreos-installer pxe ignition wrap <options>`	Wrap an Ignition config in an image.
`coreos-installer pxe ignition unwrap <options> <image_name>`	Show the wrapped Ignition config in an image.
`coreos-installer pxe ignition unwrap <options> <initrd_name>`	Show the wrapped Ignition config in an `initrd` image.
coreos-installer PXE Ignition options
Option	Description
`-i`, `--ignition-file <path>`	The Ignition config to be used. Default is `stdin`.
`-o,` `--output <path>`	Write the ISO to a new output file.
`-h`, `--help`	Print help information.

1.1.12. 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
```
1
For <installation_directory>, specify the path to the directory that you stored the installation files in.
2
To view different installation details, specify warn, debug, or error instead of info.
Example output
```
INFO Waiting up to 30m0s for the Kubernetes API at https://api.test.example.com:6443...
INFO API v1.19.0 up
INFO Waiting up to 30m0s for bootstrapping to complete...
INFO It is now safe to remove the bootstrap resources
```
The command succeeds when the Kubernetes API server signals that it has been bootstrapped on the control plane machines.
After bootstrap process is complete, remove the bootstrap machine from the load balancer.
Important
You must remove the bootstrap machine from the load balancer at this point. You can also remove or reformat the machine itself.

1.1.13. Logging in to the cluster by using the CLI

You can log in to your cluster as a default system user by exporting the cluster kubeconfig file. The kubeconfig file contains information about the cluster that is used by the CLI to connect a client to the correct cluster and API server. The file is specific to a cluster and is created during OpenShift Container Platform installation.

Prerequisites

You deployed an OpenShift Container Platform cluster.
You installed the oc CLI.

Procedure

Export the kubeadmin credentials:
```
$ export KUBECONFIG=<installation_directory>/auth/kubeconfig 1
```
1
For <installation_directory>, specify the path to the directory that you stored the installation files in.
Verify you can run oc commands successfully using the exported configuration:
```
$ oc whoami
```
Example output
```
system:admin
```

1.1.14. Approving the certificate signing requests for your machines

When you add machines to a cluster, two pending certificate signing requests (CSRs) are generated for each machine that you added. You must confirm that these CSRs are approved or, if necessary, approve them yourself. The client requests must be approved first, followed by the server requests.

Prerequisites

You added machines to your cluster.

Procedure

Confirm that the cluster recognizes the machines:
```
$ oc get nodes
```
Example output
```
NAME      STATUS    ROLES   AGE  VERSION
master-0  Ready     master  63m  v1.19.0
master-1  Ready     master  63m  v1.19.0
master-2  Ready     master  64m  v1.19.0
```
The output lists all of the machines that you created.
Note
The preceding output might not include the compute nodes, also known as worker nodes, until some CSRs are approved.

Review the pending CSRs and ensure that you see the client requests with the Pending or Approved 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:
Note
Because 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.
Note
For clusters running on platforms that are not machine API enabled, such as bare metal and other user-provisioned infrastructure, you must implement a method of automatically approving the kubelet serving certificate requests (CSRs). If a request is not approved, then the oc exec, oc rsh, and oc logs commands cannot succeed, because a serving certificate is required when the API server connects to the kubelet. Any operation that contacts the Kubelet endpoint requires this certificate approval to be in place. The method must watch for new CSRs, confirm that the CSR was submitted by the node-bootstrapper service account in the system:node or system:admin groups, and confirm the identity of the node.
- To approve them individually, run the following command for each valid CSR:
```
$ oc adm certificate approve <csr_name> 1
```
  1
  <csr_name> is the name of a CSR from the list of current CSRs.
- To approve all pending CSRs, run the following command:
```
$ oc get csr -o go-template='{{range .items}}{{if not .status}}{{.metadata.name}}{{"\n"}}{{end}}{{end}}' | xargs --no-run-if-empty oc adm certificate approve
```
  Note
  Some Operators might not become available until some CSRs are approved.

Now that your client requests are approved, you must review the server requests for each machine that you added to the cluster:

$ oc get csr

Example output

NAME        AGE     REQUESTOR                                                                   CONDITION
csr-bfd72   5m26s   system:node:ip-10-0-50-126.us-east-2.compute.internal                       Pending
csr-c57lv   5m26s   system:node:ip-10-0-95-157.us-east-2.compute.internal                       Pending
...

If the remaining CSRs are not approved, and are in the Pending status, approve the CSRs for your cluster machines:
- To approve them individually, run the following command for each valid CSR:
```
$ oc adm certificate approve <csr_name> 1
```
  1
  <csr_name> is the name of a CSR from the list of current CSRs.
- To approve all pending CSRs, run the following command:
```
$ oc get csr -o go-template='{{range .items}}{{if not .status}}{{.metadata.name}}{{"\n"}}{{end}}{{end}}' | xargs oc adm certificate approve
```

After all client and server CSRs have been approved, the machines have the Ready status. Verify this by running the following command:

$ oc get nodes

Example output

NAME      STATUS    ROLES   AGE  VERSION
master-0  Ready     master  73m  v1.20.0
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

Note

It 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.

1.1.15. Initial Operator configuration

After the control plane initializes, you must immediately configure some Operators so that they all become available.

Prerequisites

Your control plane has initialized.

Procedure

Watch the cluster components come online:

$ watch -n5 oc get clusteroperators

Example output

NAME                                       VERSION AVAILABLE   PROGRESSING   DEGRADED   SINCE
authentication                             4.6.0   True        False         False      3h56m
cloud-credential                           4.6.0   True        False         False      29h
cluster-autoscaler                         4.6.0   True        False         False      29h
config-operator                            4.6.0   True        False         False      6h39m
console                                    4.6.0   True        False         False      3h59m
csi-snapshot-controller                    4.6.0   True        False         False      4h12m
dns                                        4.6.0   True        False         False      4h15m
etcd                                       4.6.0   True        False         False      29h
image-registry                             4.6.0   True        False         False      3h59m
ingress                                    4.6.0   True        False         False      4h30m
insights                                   4.6.0   True        False         False      29h
kube-apiserver                             4.6.0   True        False         False      29h
kube-controller-manager                    4.6.0   True        False         False      29h
kube-scheduler                             4.6.0   True        False         False      29h
kube-storage-version-migrator              4.6.0   True        False         False      4h2m
machine-api                                4.6.0   True        False         False      29h
machine-approver                           4.6.0   True        False         False      6h34m
machine-config                             4.6.0   True        False         False      3h56m
marketplace                                4.6.0   True        False         False      4h2m
monitoring                                 4.6.0   True        False         False      6h31m
network                                    4.6.0   True        False         False      29h
node-tuning                                4.6.0   True        False         False      4h30m
openshift-apiserver                        4.6.0   True        False         False      3h56m
openshift-controller-manager               4.6.0   True        False         False      4h36m
openshift-samples                          4.6.0   True        False         False      4h30m
operator-lifecycle-manager                 4.6.0   True        False         False      29h
operator-lifecycle-manager-catalog         4.6.0   True        False         False      29h
operator-lifecycle-manager-packageserver   4.6.0   True        False         False      3h59m
service-ca                                 4.6.0   True        False         False      29h
storage                                    4.6.0   True        False         False      4h30m

Configure the Operators that are not available.

1.1.15.1. Image registry removed during installation

On platforms that do not provide shareable object storage, the OpenShift Image Registry Operator bootstraps itself as Removed. This allows openshift-installer to complete installations on these platform types.

After installation, you must edit the Image Registry Operator configuration to switch the managementState from Removed to Managed.

Note

The Prometheus console provides an ImageRegistryRemoved alert, for example:

"Image Registry has been removed. ImageStreamTags, BuildConfigs and DeploymentConfigs which reference ImageStreamTags may not work as expected. Please configure storage and update the config to Managed state by editing configs.imageregistry.operator.openshift.io."

1.1.15.2. Image registry storage configuration

The Image Registry Operator is not initially available for platforms that do not provide default storage. After installation, you must configure your registry to use storage so that the Registry Operator is made available.

Instructions are shown for configuring a persistent volume, which is required for production clusters. Where applicable, instructions are shown for configuring an empty directory as the storage location, which is available for only non-production clusters.

Additional instructions are provided for allowing the image registry to use block storage types by using the Recreate rollout strategy during upgrades.

1.1.15.2.1. Configuring registry storage for bare metal and other manual installations

As a cluster administrator, following installation you must configure your registry to use storage.

Prerequisites

Cluster administrator permissions.
A cluster that uses manually-provisioned Red Hat Enterprise Linux CoreOS (RHCOS) nodes, such as bare metal.
Persistent storage provisioned for your cluster, such as Red Hat OpenShift Container Storage.
Important
OpenShift 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 the configs.imageregistry/cluster resource.
Note
When 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
```
Note
If the storage type is emptyDIR, the replica number cannot be greater than 1.
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 an image-registry-storage PVC.
Check the clusteroperator status:
```
$ oc get clusteroperator image-registry
```
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
```

1.1.15.2.2. Configuring storage for the image registry in non-production clusters

You must configure storage for the Image Registry Operator. For non-production clusters, you can set the image registry to an empty directory. If you do so, all images are lost if you restart the registry.

Procedure

To set the image registry storage to an empty directory:
```
$ oc patch configs.imageregistry.operator.openshift.io cluster --type merge --patch '{"spec":{"storage":{"emptyDir":{}}}}'
```
Warning
Configure 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.

1.1.15.2.3. Configuring block registry storage

To allow the image registry to use block storage types during upgrades as a cluster administrator, you can use the Recreate rollout strategy.

Important

Block storage volumes are supported but not recommended for use with the image registry on production clusters. An installation where the registry is configured on block storage is not highly available because the registry cannot have more than one replica.

Procedure

To set the image registry storage as a block storage type, patch the registry so that it uses the Recreate rollout strategy and runs with only one (1) replica:
```
$ oc patch config.imageregistry.operator.openshift.io/cluster --type=merge -p '{"spec":{"rolloutStrategy":"Recreate","replicas":1}}'
```
Provision the PV for the block storage device, and create a PVC for that volume. The requested block volume uses the ReadWriteOnce (RWO) access mode.
Edit the registry configuration so that it references the correct PVC.

1.1.16. Completing installation on user-provisioned infrastructure

After you complete the Operator configuration, you can finish installing the cluster on infrastructure that you provide.

Prerequisites

Your control plane has initialized.
You have completed the initial Operator configuration.

Procedure

Confirm that all the cluster components are online with the following command:

$ watch -n5 oc get clusteroperators

Example output

NAME                                       VERSION AVAILABLE   PROGRESSING   DEGRADED   SINCE
authentication                             4.6.0   True        False         False      3h56m
cloud-credential                           4.6.0   True        False         False      29h
cluster-autoscaler                         4.6.0   True        False         False      29h
config-operator                            4.6.0   True        False         False      6h39m
console                                    4.6.0   True        False         False      3h59m
csi-snapshot-controller                    4.6.0   True        False         False      4h12m
dns                                        4.6.0   True        False         False      4h15m
etcd                                       4.6.0   True        False         False      29h
image-registry                             4.6.0   True        False         False      3h59m
ingress                                    4.6.0   True        False         False      4h30m
insights                                   4.6.0   True        False         False      29h
kube-apiserver                             4.6.0   True        False         False      29h
kube-controller-manager                    4.6.0   True        False         False      29h
kube-scheduler                             4.6.0   True        False         False      29h
kube-storage-version-migrator              4.6.0   True        False         False      4h2m
machine-api                                4.6.0   True        False         False      29h
machine-approver                           4.6.0   True        False         False      6h34m
machine-config                             4.6.0   True        False         False      3h56m
marketplace                                4.6.0   True        False         False      4h2m
monitoring                                 4.6.0   True        False         False      6h31m
network                                    4.6.0   True        False         False      29h
node-tuning                                4.6.0   True        False         False      4h30m
openshift-apiserver                        4.6.0   True        False         False      3h56m
openshift-controller-manager               4.6.0   True        False         False      4h36m
openshift-samples                          4.6.0   True        False         False      4h30m
operator-lifecycle-manager                 4.6.0   True        False         False      29h
operator-lifecycle-manager-catalog         4.6.0   True        False         False      29h
operator-lifecycle-manager-packageserver   4.6.0   True        False         False      3h59m
service-ca                                 4.6.0   True        False         False      29h
storage                                    4.6.0   True        False         False      4h30m

Alternatively, the following command notifies you when all of the clusters are available. It also retrieves and displays credentials:

$ ./openshift-install --dir <installation_directory> wait-for install-complete 1

1: For <installation_directory>, specify the path to the directory that you stored the installation files in.

Example output

INFO Waiting up to 30m0s for the cluster to initialize...

The command succeeds when the Cluster Version Operator finishes deploying the OpenShift Container Platform cluster from Kubernetes API server.

Important

The Ignition config files that the installation program generates contain certificates that expire after 24 hours, which are then renewed at that time. If the cluster is shut down before renewing the certificates and the cluster is later restarted after the 24 hours have elapsed, the cluster automatically recovers the expired certificates. The exception is that you must manually approve the pending node-bootstrapper certificate signing requests (CSRs) to recover kubelet certificates. See the documentation for Recovering from expired control plane certificates for more information.
It is recommended that you use Ignition config files within 12 hours after they are generated because the 24-hour certificate rotates from 16 to 22 hours after the cluster is installed. By using the Ignition config files within 12 hours, you can avoid installation failure if the certificate update runs during installation.

Confirm that the Kubernetes API server is communicating with the pods.

To view a list of all pods, use the following command:

$ oc get pods --all-namespaces

Example output

NAMESPACE                         NAME                                            READY   STATUS      RESTARTS   AGE
openshift-apiserver-operator      openshift-apiserver-operator-85cb746d55-zqhs8   1/1     Running     1          9m
openshift-apiserver               apiserver-67b9g                                 1/1     Running     0          3m
openshift-apiserver               apiserver-ljcmx                                 1/1     Running     0          1m
openshift-apiserver               apiserver-z25h4                                 1/1     Running     0          2m
openshift-authentication-operator authentication-operator-69d5d8bf84-vh2n8        1/1     Running     0          5m
...

View the logs for a pod that is listed in the output of the previous command by using the following command:
```
$ oc logs <pod_name> -n <namespace> 1
```
1
Specify the pod name and namespace, as shown in the output of the previous command.
If the pod logs display, the Kubernetes API server can communicate with the cluster machines.

1.1.17. Telemetry access for OpenShift Container Platform

In OpenShift Container Platform 4.6, the Telemetry service, which runs by default to provide metrics about cluster health and the success of updates, requires internet access. If your cluster is connected to the internet, Telemetry runs automatically, and your cluster is registered to OpenShift Cluster Manager.

After you confirm that your OpenShift Cluster Manager inventory is correct, either maintained automatically by Telemetry or manually by using OpenShift Cluster Manager, use subscription watch to track your OpenShift Container Platform subscriptions at the account or multi-cluster level.

Additional resources

See About remote health monitoring for more information about the Telemetry service

1.1.18. Next steps

Customize your cluster.
If necessary, you can opt out of remote health reporting.
Set up your registry and configure registry storage.

1.2. Installing a cluster on bare metal with network customizations

In OpenShift Container Platform version 4.6, you can install a cluster on bare metal infrastructure that you provision with customized network configuration options. By customizing your network configuration, your cluster can coexist with existing IP address allocations in your environment and integrate with existing MTU and VXLAN configurations.

You must set most of the network configuration parameters during installation, and you can modify only kubeProxy configuration parameters in a running cluster.

1.2.1. Prerequisites

Review details about the OpenShift Container Platform installation and update processes.
If you use a firewall, you must configure it to access Red Hat Insights.

1.2.2. Internet access for OpenShift Container Platform

In OpenShift Container Platform 4.6, you require access to the Internet to install your cluster.

You must have Internet access to:

Access OpenShift Cluster Manager 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.

Important

1.2.3. 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.

1.2.3.1. 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. If you are running a three-node cluster, running zero compute machines is supported. Running one compute machine is not supported.

Note

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.

Important

To maintain high availability of your cluster, use separate physical hosts for these cluster machines.

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.

1.2.3.2. Network connectivity requirements

1.2.3.3. Minimum resource requirements

Each cluster machine must meet the following minimum requirements:

Machine	Operating System	CPU ^[1]	RAM	Storage	IOPS ^[2]
Bootstrap	RHCOS	4	16 GB	100 GB	300
Control plane	RHCOS	4	16 GB	100 GB	300
Compute	RHCOS or RHEL 7.9	2	8 GB	100 GB	300

One CPU is equivalent to one 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 = CPUs.
OpenShift Container Platform and Kubernetes are sensitive to disk performance, and faster storage is recommended, particularly for etcd on the control plane nodes which require a 10 ms p99 fsync duration. Note that on many cloud platforms, storage size and IOPS scale together, so you might need to over-allocate storage volume to obtain sufficient performance.

1.2.3.4. Certificate signing requests management

1.2.4. 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.

1.2.4.1. 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.

Table 1.12. All machines to all machines
Protocol	Port	Description
ICMP	N/A	Network reachability tests
TCP	`1936`	Metrics
	`9000`-`9999`	Host level services, including the node exporter on ports `9100`-`9101` and the Cluster Version Operator on port `9099`.
	`10250`-`10259`	The default ports that Kubernetes reserves
	`10256`	openshift-sdn
UDP	`4789`	VXLAN and Geneve
	`6081`	VXLAN and Geneve
	`9000`-`9999`	Host level services, including the node exporter on ports `9100`-`9101`.
TCP/UDP	`30000`-`32767`	Kubernetes node port

Table 1.13. All machines to control plane
Protocol	Port	Description
TCP	`6443`	Kubernetes API

Table 1.14. Control plane machines to control plane machines
Protocol	Port	Description
TCP	`2379`-`2380`	etcd server and peer ports

Network topology requirements

The infrastructure that you provision for your cluster must meet the following network topology requirements.

Important

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.

Important

Do not configure session persistence for an API load balancer.

Configure the following ports on both the front and back of the load balancers:

Table 1.15. 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

Note

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 1.16. 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

Tip

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.

Note

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.

NTP configuration

If a DHCP server provides NTP server information, the chrony time service on the Red Hat Enterprise Linux CoreOS (RHCOS) machines read the information and can sync the clock with the NTP servers.

Additional resources

Configuring chrony time service

1.2.4.2. User-provisioned DNS requirements

Table 1.17. Required DNS records
Component	Record	Description
Kubernetes API	`api.<cluster_name>.<base_domain>.`	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.
Kubernetes API	`api-int.<cluster_name>.<base_domain>.`	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	`*.apps.<cluster_name>.<base_domain>.`	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	`bootstrap.<cluster_name>.<base_domain>.`	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	`<master><n>.<cluster_name>.<base_domain>.`	DNS A/AAAA or CNAME records and DNS PTR records to identify each machine for the control plane nodes (also known as the master nodes). These records must be resolvable by the nodes within the cluster.
Worker hosts	`<worker><n>.<cluster_name>.<base_domain>.`	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.

Tip

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.

Example 1.3. 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 1.4. 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

1.2.5. Generating an SSH private key and adding it to the agent

Note

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.

Note

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.
Note
If 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 the ed25519 algorithm. Instead, create a key that uses the rsa or ecdsa algorithm.
Start the ssh-agent process as a background task:
```
$ eval "$(ssh-agent -s)"
```
Example output
```
Agent pid 31874
```
Note
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

Next steps

When you install OpenShift Container Platform, provide the SSH public key to the installation program.

1.2.6. Obtaining the installation program

Before you install OpenShift Container Platform, download the installation file on a local computer.

Prerequisites

You have a computer that runs Linux or macOS, with 500 MB of local disk space

Procedure

Access the Infrastructure Provider page on the OpenShift Cluster Manager site. If you have a Red Hat account, log in with your credentials. If you do not, create an account.
Select your infrastructure provider.
Navigate to the page for your installation type, download the installation program for your operating system, and place the file in the directory where you will store the installation configuration files.
Important
The installation program creates several files on the computer that you use to install your cluster. You must keep the installation program and the files that the installation program creates after you finish installing the cluster. Both files are required to delete the cluster.
Important
Deleting the files created by the installation program does not remove your cluster, even if the cluster failed during installation. To remove your cluster, complete the OpenShift Container Platform uninstallation procedures for your specific cloud provider.
Extract the installation program. For example, on a computer that uses a Linux operating system, run the following command:
```
$ tar xvf openshift-install-linux.tar.gz
```
Download your installation pull secret from the Red Hat OpenShift Cluster Manager. This pull secret allows you to authenticate with the services that are provided by the included authorities, including Quay.io, which serves the container images for OpenShift Container Platform components.

1.2.7. Installing the OpenShift 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.

Important

If you installed an earlier version of oc, you cannot use it to complete all of the commands in OpenShift Container Platform 4.6. Download and install the new version of oc.

1.2.7.1. Installing the OpenShift CLI on Linux

You can install the OpenShift CLI (oc) binary on Linux by using the following procedure.

Procedure

Navigate to the OpenShift Container Platform downloads page on the Red Hat Customer Portal.
Select the appropriate version in the Version drop-down menu.
Click Download Now next to the OpenShift v4.6 Linux Client entry and save the file.
Unpack the archive:
```
$ tar xvzf <file>
```
Place the oc binary in a directory that is on your PATH.
To check your PATH, execute the following command:
```
$ echo $PATH
```

After you install the OpenShift CLI, it is available using the oc command:

$ oc <command>

1.2.7.2. Installing the OpenShift CLI on Windows

You can install the OpenShift CLI (oc) binary on Windows by using the following procedure.

Procedure

Navigate to the OpenShift Container Platform downloads page on the Red Hat Customer Portal.
Select the appropriate version in the Version drop-down menu.
Click Download Now next to the OpenShift v4.6 Windows Client entry and save the file.
Unzip the archive with a ZIP program.
Move the oc binary to a directory that is on your PATH.
To check your PATH, open the command prompt and execute the following command:
```
C:\> path
```

After you install the OpenShift CLI, it is available using the oc command:

C:\> oc <command>

1.2.7.3. Installing the OpenShift CLI on macOS

You can install the OpenShift CLI (oc) binary on macOS by using the following procedure.

Procedure

Navigate to the OpenShift Container Platform downloads page on the Red Hat Customer Portal.
Select the appropriate version in the Version drop-down menu.
Click Download Now next to the OpenShift v4.6 MacOSX Client entry and save the file.
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 OpenShift CLI, it is available using the oc command:

$ oc <command>

1.2.8. 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>
```
Important
You 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>.
Note
You 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.
Important
The install-config.yaml file is consumed during the next step of the installation process. You must back it up now.

1.2.8.1. Installation configuration parameters

Note

After installation, you cannot modify these parameters in the install-config.yaml file.

Important

1.2.8.1.1. Required configuration parameters

Required installation configuration parameters are described in the following table:

Table 1.18. Required parameters
Parameter	Description	Values
`apiVersion`	The API version for the `install-config.yaml` content. The current version is `v1`. The installer may also support older API versions.	String
`baseDomain`	The base domain of your cloud provider. The base domain is used to create routes to your OpenShift Container Platform cluster components. The full DNS name for your cluster is a combination of the `baseDomain` and `metadata.name` parameter values that uses the `<metadata.name>.<baseDomain>` format.	A fully-qualified domain or subdomain name, such as `example.com`.
`metadata`	Kubernetes resource `ObjectMeta`, from which only the `name` parameter is consumed.	Object
`metadata.name`	The name of the cluster. DNS records for the cluster are all subdomains of `{{.metadata.name}}.{{.baseDomain}}`.	String of lowercase letters, hyphens (`-`), and periods (`.`), such as `dev`.
`platform`	The configuration for the specific platform upon which to perform the installation: `aws`, `baremetal`, `azure`, `openstack`, `ovirt`, `vsphere`. For additional information about `platform.<platform>` parameters, consult the following table for your specific platform.	Object
`pullSecret`	Get a pull secret from the Red Hat OpenShift Cluster Manager to authenticate downloading container images for OpenShift Container Platform components from services such as Quay.io.	{ "auths":{ "cloud.openshift.com":{ "auth":"b3Blb=", "email":"you@example.com" }, "quay.io":{ "auth":"b3Blb=", "email":"you@example.com" } } }

1.2.8.1.2. Network configuration parameters

Only IPv4 addresses are supported.

Table 1.19. Network parameters
Parameter	Description	Values
`networking`	The configuration for the cluster network.	Object Note You cannot modify parameters specified by the `networking` object after installation.
`networking.networkType`	The cluster network provider Container Network Interface (CNI) plug-in to install.	Either `OpenShiftSDN` or `OVNKubernetes`. The default value is `OpenShiftSDN`.
`networking.clusterNetwork`	The IP address blocks for pods. The default value is `10.128.0.0/14` with a host prefix of `/23`. If you specify multiple IP address blocks, the blocks must not overlap.	An array of objects. For example: networking: clusterNetwork: - cidr: 10.128.0.0/14 hostPrefix: 23
`networking.clusterNetwork.cidr`	Required if you use `networking.clusterNetwork`. An IP address block. An IPv4 network.	An IP address block in Classless Inter-Domain Routing (CIDR) notation. The prefix length for an IPv4 block is between `0` and `32`.
`networking.clusterNetwork.hostPrefix`	The subnet prefix length to assign to each individual node. For example, if `hostPrefix` is set to `23` then each node is assigned a `/23` subnet out of the given `cidr`. A `hostPrefix` value of `23` provides 510 (2^(32 - 23) - 2) pod IP addresses.	A subnet prefix. The default value is `23`.
`networking.serviceNetwork`	The IP address block for services. The default value is `172.30.0.0/16`. The OpenShift SDN and OVN-Kubernetes network providers support only a single IP address block for the service network.	An array with an IP address block in CIDR format. For example: networking: serviceNetwork: - 172.30.0.0/16
`networking.machineNetwork`	The IP address blocks for machines. If you specify multiple IP address blocks, the blocks must not overlap.	An array of objects. For example: networking: machineNetwork: - cidr: 10.0.0.0/16
`networking.machineNetwork.cidr`	Required if you use `networking.machineNetwork`. An IP address block. The default value is `10.0.0.0/16` for all platforms other than libvirt. For libvirt, the default value is `192.168.126.0/24`.	An IP network block in CIDR notation. For example, `10.0.0.0/16`. Note Set the `networking.machineNetwork` to match the CIDR that the preferred NIC resides in.

1.2.8.1.3. Optional configuration parameters

Optional installation configuration parameters are described in the following table:

Table 1.20. Optional parameters
Parameter	Description	Values
`additionalTrustBundle`	A PEM-encoded X.509 certificate bundle that is added to the nodes' trusted certificate store. This trust bundle may also be used when a proxy has been configured.	String
`compute`	The configuration for the machines that comprise the compute nodes.	Array of machine-pool objects. For details, see the following "Machine-pool" table.
`compute.architecture`	Determines the instruction set architecture of the machines in the pool. Currently, heteregeneous clusters are not supported, so all pools must specify the same architecture. Valid values are `amd64` (the default).	String
`compute.hyperthreading`	Whether to enable or disable simultaneous multithreading, or `hyperthreading`, on compute machines. By default, simultaneous multithreading is enabled to increase the performance of your machines' cores. Important If you disable simultaneous multithreading, ensure that your capacity planning accounts for the dramatically decreased machine performance.	`Enabled` or `Disabled`
`compute.name`	Required if you use `compute`. The name of the machine pool.	`worker`
`compute.platform`	Required if you use `compute`. Use this parameter to specify the cloud provider to host the worker machines. This parameter value must match the `controlPlane.platform` parameter value.	`aws`, `azure`, `gcp`, `openstack`, `ovirt`, `vsphere`, or `{}`
`compute.replicas`	The number of compute machines, which are also known as worker machines, to provision.	A positive integer greater than or equal to `2`. The default value is `3`.
`controlPlane`	The configuration for the machines that comprise the control plane.	Array of `MachinePool` objects. For details, see the following "Machine-pool" table.
`controlPlane.architecture`	Determines the instruction set architecture of the machines in the pool. Currently, heterogeneous clusters are not supported, so all pools must specify the same architecture. Valid values are `amd64` (the default).	String
`controlPlane.hyperthreading`	Whether to enable or disable simultaneous multithreading, or `hyperthreading`, on control plane machines. By default, simultaneous multithreading is enabled to increase the performance of your machines' cores. Important If you disable simultaneous multithreading, ensure that your capacity planning accounts for the dramatically decreased machine performance.	`Enabled` or `Disabled`
`controlPlane.name`	Required if you use `controlPlane`. The name of the machine pool.	`master`
`controlPlane.platform`	Required if you use `controlPlane`. Use this parameter to specify the cloud provider that hosts the control plane machines. This parameter value must match the `compute.platform` parameter value.	`aws`, `azure`, `gcp`, `openstack`, `ovirt`, `vsphere`, or `{}`
`controlPlane.replicas`	The number of control plane machines to provision.	The only supported value is `3`, which is the default value.
`credentialsMode`	The Cloud Credential Operator (CCO) mode. If no mode is specified, the CCO dynamically tries to determine the capabilities of the provided credentials, with a preference for mint mode on the platforms where multiple modes are supported. Note Not all CCO modes are supported for all cloud providers. For more information on CCO modes, see the Cloud Credential Operator entry in the Red Hat Operators reference content.	`Mint`, `Passthrough`, `Manual`, or an empty string (`""`).
`fips`	Enable or disable FIPS mode. The default is `false` (disabled). 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. Important The use of FIPS Validated / Modules in Process cryptographic libraries is only supported on OpenShift Container Platform deployments on the `x86_64` architecture. Note If you are using Azure File storage, you cannot enable FIPS mode.	`false` or `true`
`imageContentSources`	Sources and repositories for the release-image content.	Array of objects. Includes a `source` and, optionally, `mirrors`, as described in the following rows of this table.
`imageContentSources.source`	Required if you use `imageContentSources`. Specify the repository that users refer to, for example, in image pull specifications.	String
`imageContentSources.mirrors`	Specify one or more repositories that may also contain the same images.	Array of strings
`publish`	How to publish or expose the user-facing endpoints of your cluster, such as the Kubernetes API, OpenShift routes.	`Internal` or `External`. The default value is `External`. Setting this field to `Internal` is not supported on non-cloud platforms. Important If the value of the field is set to `Internal`, the cluster will become non-functional. For more information, refer to BZ#1953035.
`sshKey`	The SSH key or keys to authenticate access your cluster machines. Note For production OpenShift Container Platform clusters on which you want to perform installation debugging or disaster recovery, specify an SSH key that your `ssh-agent` process uses.	One or more keys. For example: sshKey: <key1> <key2> <key3>

1.2.8.2. Sample install-config.yaml file for bare metal

You can customize the install-config.yaml file to specify more details about your OpenShift Container Platform cluster’s platform or modify the values of the required parameters.

apiVersion: v1
baseDomain: example.com 1
compute: 2
- hyperthreading: Enabled 3
  name: worker
  replicas: 0 4
controlPlane: 5
  hyperthreading: Enabled 6
  name: master
  replicas: 3 7
metadata:
  name: test 8
networking:
  clusterNetwork:
  - cidr: 10.128.0.0/14 9
    hostPrefix: 23 10
  networkType: 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 the compute section is a sequence of mappings. To meet the requirements of the different data structures, the first line of the compute section must begin with a hyphen, -, and the first line of the controlPlane section must not. 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 to Disabled. If you disable SMT, you must disable it in all cluster machines; this includes both control plane and compute machines.
Note
Simultaneous multithreading (SMT) is enabled by default. If SMT is not enabled in your BIOS settings, the hyperthreading parameter has no effect.
Important
If you disable hyperthreading, whether in the BIOS or in the install-config.yaml, ensure that your capacity planning accounts for the dramatically decreased machine performance.
4: You must set the value of the replicas parameter to 0. 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.
Note
Class E CIDR range is reserved for a future use. To use the Class E CIDR range, you must ensure your networking environment accepts the IP addresses within the Class E CIDR range.
10: The subnet prefix length to assign to each individual node. For example, if hostPrefix is set to 23, then each node is assigned a /23 subnet out of the given cidr, 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. This block must not overlap with existing physical networks. If you need to access the services from an external network, configure load balancers and routers to manage the traffic.
12: You must set the platform to none. You cannot provide additional platform configuration variables for your platform.
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.
Important
The use of FIPS Validated / Modules in Process cryptographic libraries is only supported on OpenShift Container Platform deployments on the x86_64 architecture.
14: The pull secret from the Red Hat OpenShift Cluster Manager. This pull secret allows you to authenticate with the services that are provided by the included authorities, including Quay.io, which serves the container images for OpenShift Container Platform components.
15: The public portion of the default SSH key for the core user in Red Hat Enterprise Linux CoreOS (RHCOS).
Note
For 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.

1.2.9. Network configuration phases

When specifying a cluster configuration prior to installation, there are several phases in the installation procedures when you can modify the network configuration:

Phase 1

After entering the openshift-install create install-config command. In the install-config.yaml file, you can customize the following network-related fields:

networking.networkType
networking.clusterNetwork
networking.serviceNetwork
networking.machineNetwork
For more information on these fields, refer to "Installation configuration parameters".
Note
Set the networking.machineNetwork to match the CIDR that the preferred NIC resides in.

Phase 2

After entering the openshift-install create manifests command. If you must specify advanced network configuration, during this phase you can define a customized Cluster Network Operator manifest with only the fields you want to modify.

You cannot override the values specified in phase 1 in the install-config.yaml file during phase 2. However, you can further customize the cluster network provider during phase 2.

1.2.10. Specifying advanced network configuration

You can use advanced configuration customization to integrate your cluster into your existing network environment by specifying additional configuration for your cluster network provider. You can specify advanced network configuration only before you install the cluster.

Important

Modifying the OpenShift Container Platform manifest files created by the installation program is not supported. Applying a manifest file that you create, as in the following procedure, is supported.

Prerequisites

Create the install-config.yaml file and complete any modifications to it.
Create the Ignition config files for your cluster.

Procedure

Change to the directory that contains the installation program and create the manifests:
```
$ ./openshift-install create manifests --dir <installation_directory>
```
where:
<installation_directory>
Specifies the name of the directory that contains the install-config.yaml file for your cluster.
Create a stub manifest file for the advanced network configuration that is named cluster-network-03-config.yml in the <installation_directory>/manifests/ directory:
```
$ cat <<EOF > <installation_directory>/manifests/cluster-network-03-config.yml
apiVersion: operator.openshift.io/v1
kind: Network
metadata:
  name: cluster
spec:
EOF
```
where:
<installation_directory>
Specifies the directory name that contains the manifests/ directory for your cluster.
Open the cluster-network-03-config.yml file in an editor and specify the advanced network configuration for your cluster, such as in the following example:
Specify a different VXLAN port for the OpenShift SDN network provider
```
apiVersion: operator.openshift.io/v1
kind: Network
metadata:
  name: cluster
spec:
  defaultNetwork:
    openshiftSDNConfig:
      vxlanPort: 4800
```
Save the cluster-network-03-config.yml file and quit the text editor.
Optional: Back up the manifests/cluster-network-03-config.yml file. The installation program deletes the manifests/ directory when creating the cluster.

1.2.11. Cluster Network Operator configuration

The configuration for the cluster network is specified as part of the Cluster Network Operator (CNO) configuration and stored in a custom resource (CR) object that is named cluster. The CR specifies the fields for the Network API in the operator.openshift.io API group.

The CNO configuration inherits the following fields during cluster installation from the Network API in the Network.config.openshift.io API group and these fields cannot be changed:

clusterNetwork: IP address pools from which pod IP addresses are allocated.
serviceNetwork: IP address pool for services.
defaultNetwork.type: Cluster network provider, such as OpenShift SDN or OVN-Kubernetes.

You can specify the cluster network provider configuration for your cluster by setting the fields for the defaultNetwork object in the CNO object named cluster.

1.2.11.1. Cluster Network Operator configuration object

The fields for the Cluster Network Operator (CNO) are described in the following table:

Table 1.21. Cluster Network Operator configuration object
Field	Type	Description
`metadata.name`	`string`	The name of the CNO object. This name is always `cluster`.
`spec.clusterNetwork`	`array`	A list specifying the blocks of IP addresses from which pod IP addresses are allocated and the subnet prefix length assigned to each individual node in the cluster. For example: spec: clusterNetwork: - cidr: 10.128.0.0/19 hostPrefix: 23 - cidr: 10.128.32.0/19 hostPrefix: 23 This value is ready-only and specified in the `install-config.yaml` file.
`spec.serviceNetwork`	`array`	A block of IP addresses for services. The OpenShift SDN and OVN-Kubernetes Container Network Interface (CNI) network providers support only a single IP address block for the service network. For example: spec: serviceNetwork: - 172.30.0.0/14 This value is ready-only and specified in the `install-config.yaml` file.
`spec.defaultNetwork`	`object`	Configures the Container Network Interface (CNI) cluster network provider for the cluster network.
`spec.kubeProxyConfig`	`object`	The fields for this object specify the kube-proxy configuration. If you are using the OVN-Kubernetes cluster network provider, the kube-proxy configuration has no effect.

defaultNetwork object configuration

The values for the defaultNetwork object are defined in the following table:

Table 1.22. defaultNetwork object
Field	Type	Description
`type`	`string`	Either `OpenShiftSDN` or `OVNKubernetes`. The cluster network provider is selected during installation. This value cannot be changed after cluster installation. Note OpenShift Container Platform uses the OpenShift SDN Container Network Interface (CNI) cluster network provider by default.
`openshiftSDNConfig`	`object`	This object is only valid for the OpenShift SDN cluster network provider.
`ovnKubernetesConfig`	`object`	This object is only valid for the OVN-Kubernetes cluster network provider.

Configuration for the OpenShift SDN CNI cluster network provider

The following table describes the configuration fields for the OpenShift SDN Container Network Interface (CNI) cluster network provider.

Table 1.23. openshiftSDNConfig object
Field	Type	Description
`mode`	`string`	Configures the network isolation mode for OpenShift SDN. The default value is `NetworkPolicy`. The values `Multitenant` and `Subnet` are available for backwards compatibility with OpenShift Container Platform 3.x but are not recommended. This value cannot be changed after cluster installation.
`mtu`	`integer`	The maximum transmission unit (MTU) for the VXLAN overlay network. This is detected automatically based on the MTU of the primary network interface. You do not normally need to override the detected MTU. If the auto-detected value is not what you expected it to be, confirm that the MTU on the primary network interface on your nodes is correct. You cannot use this option to change the MTU value of the primary network interface on the nodes. If your cluster requires different MTU values for different nodes, you must set this value to `50` less than the lowest MTU value in your cluster. For example, if some nodes in your cluster have an MTU of `9001`, and some have an MTU of `1500`, you must set this value to `1450`. This value cannot be changed after cluster installation.
`vxlanPort`	`integer`	The port to use for all VXLAN packets. The default value is `4789`. This value cannot be changed after cluster installation. If you are running in a virtualized environment with existing nodes that are part of another VXLAN network, then you might be required to change this. For example, when running an OpenShift SDN overlay on top of VMware NSX-T, you must select an alternate port for the VXLAN, because both SDNs use the same default VXLAN port number. On Amazon Web Services (AWS), you can select an alternate port for the VXLAN between port `9000` and port `9999`.

Example OpenShift SDN configuration

defaultNetwork:
  type: OpenShiftSDN
  openshiftSDNConfig:
    mode: NetworkPolicy
    mtu: 1450
    vxlanPort: 4789

Configuration for the OVN-Kubernetes CNI cluster network provider

The following table describes the configuration fields for the OVN-Kubernetes CNI cluster network provider.

Table 1.24. ovnKubernetesConfig object
Field	Type	Description
`mtu`	`integer`	The maximum transmission unit (MTU) for the Geneve (Generic Network Virtualization Encapsulation) overlay network. This is detected automatically based on the MTU of the primary network interface. You do not normally need to override the detected MTU. If the auto-detected value is not what you expected it to be, confirm that the MTU on the primary network interface on your nodes is correct. You cannot use this option to change the MTU value of the primary network interface on the nodes. If your cluster requires different MTU values for different nodes, you must set this value to `100` less than the lowest MTU value in your cluster. For example, if some nodes in your cluster have an MTU of `9001`, and some have an MTU of `1500`, you must set this value to `1400`. This value cannot be changed after cluster installation.
`genevePort`	`integer`	The port to use for all Geneve packets. The default value is `6081`. This value cannot be changed after cluster installation.

Example OVN-Kubernetes configuration

defaultNetwork:
  type: OVNKubernetes
  ovnKubernetesConfig:
    mtu: 1400
    genevePort: 6081

kubeProxyConfig object configuration

The values for the kubeProxyConfig object are defined in the following table:

Table 1.25. kubeProxyConfig object
Field	Type	Description
`iptablesSyncPeriod`	`string`	The refresh period for `iptables` rules. The default value is `30s`. Valid suffixes include `s`, `m`, and `h` and are described in the Go `time` package documentation. Note Because of performance improvements introduced in OpenShift Container Platform 4.3 and greater, adjusting the `iptablesSyncPeriod` parameter is no longer necessary.
`proxyArguments.iptables-min-sync-period`	`array`	The minimum duration before refreshing `iptables` rules. This field ensures that the refresh does not happen too frequently. Valid suffixes include `s`, `m`, and `h` and are described in the Go `time` package. The default value is: kubeProxyConfig: proxyArguments: iptables-min-sync-period: - 0s

1.2.12. Creating the Ignition config files

Because you must manually start the cluster machines, you must generate the Ignition config files that the cluster needs to make its machines.

Important

The Ignition config files that the installation program generates contain certificates that expire after 24 hours, which are then renewed at that time. If the cluster is shut down before renewing the certificates and the cluster is later restarted after the 24 hours have elapsed, the cluster automatically recovers the expired certificates. The exception is that you must manually approve the pending node-bootstrapper certificate signing requests (CSRs) to recover kubelet certificates. See the documentation for Recovering from expired control plane certificates for more information.
It is recommended that you use Ignition config files within 12 hours after they are generated because the 24-hour certificate rotates from 16 to 22 hours after the cluster is installed. By using the Ignition config files within 12 hours, you can avoid installation failure if the certificate update runs during installation.

Prerequisites

Obtain the OpenShift Container Platform installation program and the pull secret for your cluster.

Procedure

Obtain the Ignition config files:
```
$ ./openshift-install create ignition-configs --dir <installation_directory> 1
```
1
For <installation_directory>, specify the directory name to store the files that the installation program creates.
Important
If you created an install-config.yaml file, specify the directory that contains it. Otherwise, specify an empty directory. Some installation assets, like bootstrap X.509 certificates have short expiration intervals, so you must not reuse an installation directory. If you want to reuse individual files from another cluster installation, you can copy them into your directory. However, the file names for the installation assets might change between releases. Use caution when copying installation files from an earlier OpenShift Container Platform version.
The following files are generated in the directory:
```
.
├── auth
│   ├── kubeadmin-password
│   └── kubeconfig
├── bootstrap.ign
├── master.ign
├── metadata.json
└── worker.ign
```

1.2.13. Installing RHCOS and starting the OpenShift Container Platform bootstrap process

To install RHCOS on the machines, follow either the steps to use an ISO image or network PXE booting.

Note

You can configure RHCOS during ISO and PXE installations by using the following methods:

Kernel arguments: You can use kernel arguments to provide installation-specific information. For example, you can specify the locations of the RHCOS installation files that you uploaded to your HTTP server and the location of the Ignition config file for the type of node you are installing. For a PXE installation, you can use the APPEND parameter to pass the arguments to the kernel of the live installer. For an ISO installation, you can interrupt the live installation boot process to add the kernel arguments. In both installation cases, you can use special coreos.inst.* arguments to direct the live installer, as well as standard installation boot arguments for turning standard kernel services on or off.
Ignition configs: OpenShift Container Platform Ignition config files (*.ign) are specific to the type of node you are installing. You pass the location of a bootstrap, control plane, or compute node Ignition config file during the RHCOS installation so that it takes effect on first boot. In special cases, you can create a separate, limited Ignition config to pass to the live system. That Ignition config could do a certain set of tasks, such as reporting success to a provisioning system after completing installation. This special Ignition config is consumed by the coreos-installer to be applied on first boot of the installed system. Do not provide the standard control plane and compute node Ignition configs to the live ISO directly.
coreos-installer: You can boot the live ISO installer to a shell prompt, which allows you to prepare the permanent system in a variety of ways before first boot. In particular, you can run the coreos-installer command to identify various artifacts to include, work with disk partitions, and set up networking. In some cases, you can configure features on the live system and copy them to the installed system.

Note

As of OpenShift Container Platform 4.6, the RHCOS ISO and other installation artifacts provide support for installation on disks with 4K sectors.

1.2.13.1. Creating Red Hat Enterprise Linux CoreOS (RHCOS) machines using an ISO image

Before you install a cluster on 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 can be accessed from your computer, and from the machines that you create.

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.
Important
If 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.
Important
The RHCOS images might not change with every release of OpenShift Container Platform. You must download images with the highest version that is less than or equal to the OpenShift Container Platform version that you install. Use the image versions that match your OpenShift Container Platform version if they are available. Use only ISO images for this procedure. RHCOS qcow2 images are not supported for this installation type.
ISO file names resemble the following example:
rhcos-<version>-live.<architecture>.iso
Use the ISO to start the RHCOS installation. Use one of the following installation options:
- Burn the ISO image to a disk and boot it directly.
- Use ISO redirection via a LOM interface.
Boot the ISO image. You can interrupt the installation boot process to add kernel arguments. However, for this ISO procedure you should use the coreos-installer command instead of adding kernel arguments. If you run the live installer without options or interruption, the installer boots up to a shell prompt on the live system, ready for you to install RHCOS to disk.
Review the Advanced RHCOS installation reference section for different ways of configuring features, such as networking and disk partitions, before running the coreos-installer.
Run the coreos-installer command. At a minimum, you must identify the Ignition config file location for your node type, and the location of the disk you are installing to. Here is an example:
```
$ sudo coreos-installer install \
     --ignition-url=https://host/worker.ign /dev/sda
```
After RHCOS installs, the system reboots. During the system reboot, it applies the Ignition config file that you specified.
Continue to create the other machines for your cluster.
Important
You 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.

1.2.13.2. Creating Red Hat Enterprise Linux CoreOS (RHCOS) machines by PXE or iPXE booting

Before you install a cluster that uses manually-provisioned RHCOS nodes, such as bare metal, you must create RHCOS machines for it to use. You can use PXE or iPXE booting to create the machines.

Prerequisites

Obtain the Ignition config files for your cluster.
Configure suitable PXE or iPXE infrastructure.
Have access to an HTTP 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.
Important
You can add or change configuration settings in your Ignition configs before saving them to your HTTP server. If you plan to add more compute machines to your cluster after you finish installation, do not delete these files.
Obtain the RHCOS kernel, initramfs and rootfs files from the RHCOS image mirror page.
Important
The RHCOS artifacts might not change with every release of OpenShift Container Platform. You must download artifacts with the highest version that is less than or equal to the OpenShift Container Platform version that you install. Only use the appropriate kernel, initramfs, and rootfs artifacts described below for this procedure. RHCOS qcow2 images are not supported for this installation type.
The file names contain the OpenShift Container Platform version number. They resemble the following examples:
- kernel: rhcos-<version>-live-kernel-<architecture>
- initramfs: rhcos-<version>-live-initramfs.<architecture>.img
- rootfs: rhcos-<version>-live-rootfs.<architecture>.img
Upload the additional files that are required for your booting method:
- For traditional PXE, upload the kernel and initramfs files to your TFTP server and the rootfs file to your HTTP server.
- For iPXE, upload the kernel, initramfs, and rootfs files to your HTTP server.
  Important
  If you plan to add more compute machines to your cluster after you finish installation, do not delete these files.
Configure the network boot infrastructure so that the machines boot from their local disks after RHCOS is installed on them.
Configure PXE or iPXE installation for the RHCOS images.
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 http://<HTTP_server>/rhcos-<version>-live-kernel-<architecture> 1
    APPEND initrd=http://<HTTP_server>/rhcos-<version>-live-initramfs.<architecture>.img coreos.live.rootfs_url=http://<HTTP_server>/rhcos-<version>-live-rootfs.<architecture>.img coreos.inst.install_dev=/dev/sda coreos.inst.ignition_url=http://<HTTP_server>/bootstrap.ign 2 3
```
  1
  Specify the location of the live kernel file that you uploaded to your HTTP server. The URL must be HTTP, TFTP, or FTP; HTTPS and NFS are not supported.
  2
  If you use multiple NICs, specify a single interface in the ip option. For example, to use DHCP on a NIC that is named eno1, set ip=eno1:dhcp.
  3
  Specify locations of the RHCOS files that you uploaded to your HTTP server. The initrd parameter value is the location of the initramfs file, the coreos.live.rootfs_url parameter value is the location of the rootfs file, and the coreos.inst.ignition_url parameter value is the location of the bootstrap Ignition config file. You can also add more kernel arguments to the APPEND line to configure networking or other boot options.
  Note
  This 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 the APPEND line. For example, add console=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?.
- For iPXE:
```
kernel http://<HTTP_server>/rhcos-<version>-live-kernel-<architecture> initrd=main coreos.live.rootfs_url=http://<HTTP_server>/rhcos-<version>-live-rootfs.<architecture>.img coreos.inst.install_dev=/dev/sda coreos.inst.ignition_url=http://<HTTP_server>/bootstrap.ign 1 2
initrd --name main http://<HTTP_server>/rhcos-<version>-live-initramfs.<architecture>.img 3
boot
```
  1
  Specify locations of the RHCOS files that you uploaded to your HTTP server. The kernel parameter value is the location of the kernel file, the initrd=main argument is needed for booting on UEFI systems, the coreos.live.rootfs_url parameter value is the location of the rootfs file, and the coreos.inst.ignition_url parameter value is the location of the bootstrap Ignition config file.
  2
  If you use multiple NICs, specify a single interface in the ip option. For example, to use DHCP on a NIC that is named eno1, set ip=eno1:dhcp.
  3
  Specify the location of the initramfs file that you uploaded to your HTTP server.
  Note
  This 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 the kernel line. For example, add console=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 PXE UEFI, perform the following actions:
1. Provide the shimx64.efi and grubx64.efi EFI binaries and the grub.cfg file that are required for booting the system.
  - Extract the necessary EFI binaries by mounting the RHCOS ISO to your host and then mounting the images/efiboot.img file to your host:
    $ mkdir -p /mnt/iso
    $ mkdir -p /mnt/efiboot
    $ mount -o loop rhcos-installer.x86_64.iso /mnt/iso
    $ mount -o loop,ro /mnt/iso/images/efiboot.img /mnt/efiboot
  - From the efiboot.img mount point, copy the EFI/redhat/shimx64.efi and EFI/redhat/grubx64.efi files to your TFTP server:
    $ cp /mnt/efiboot/EFI/redhat/shimx64.efi .
    $ cp /mnt/efiboot/EFI/redhat/grubx64.efi .
    $ umount /mnt/efiboot
    $ umount /mnt/iso
  - Copy the EFI/redhat/grub.cfg file that is included in the RHCOS ISO to your TFTP server.
2. Edit the grub.cfg file to include arguments similar to the following:
```
menuentry 'Install Red Hat Enterprise Linux CoreOS' --class fedora --class gnu-linux --class gnu --class os {
	linuxefi rhcos-<version>-live-kernel-<architecture> coreos.inst.install_dev=/dev/sda coreos.live.rootfs_url=http://<HTTP_server>/rhcos-<version>-live-rootfs.<architecture>.img coreos.inst.ignition_url=http://<HTTP_server>/bootstrap.ign
	initrdefi rhcos-<version>-live-initramfs.<architecture>.img
}
```
  where:
  rhcos-<version>-live-kernel-<architecture>
  Specifies the kernel file that you uploaded to your TFTP server.
  http://<HTTP_server>/rhcos-<version>-live-rootfs.<architecture>.img
  Specifies the location of the live rootfs image that you uploaded to your HTTP server.
  http://<HTTP_server>/bootstrap.ign
  Specifies the location of the bootstrap Ignition config file that you uploaded to your HTTP server.
  rhcos-<version>-live-initramfs.<architecture>.img
  Specifies the location of the initramfs file that you uploaded to your TFTP server.
  Note
  For more information on how to configure a PXE server for UEFI boot, see the Red Hat Knowledgebase article: How to configure/setup a PXE server for UEFI boot for Red Hat Enterprise Linux?.
Continue to create the machines for your cluster.
Important
You 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.

1.2.13.3. Advanced Red Hat Enterprise Linux CoreOS (RHCOS) installation configuration

Passing kernel arguments to the live installer
Running coreos-installer manually from the live system
Embedding Ignition configs in an ISO

1.2.13.3.1. Using advanced networking options for PXE and ISO installations

Pass special kernel parameters when you boot the live installer.
Use a machine config to copy networking files to the installed system.
Configure networking from a live installer shell prompt, then copy those settings to the installed system so that they take effect when the installed system first boots.

To configure a PXE or iPXE installation, use one of the following options:

See the "Advanced RHCOS installation reference" tables.
Use a machine config to copy networking files to the installed system.

To configure an ISO installation, use the following procedure.

Procedure

Boot the ISO installer.
From the live system shell prompt, configure networking for the live system using available RHEL tools, such as nmcli or nmtui.
Run the coreos-installer command to install the system, adding the --copy-network option to copy networking configuration. For example:
```
$ coreos-installer install --copy-network \
     --ignition-url=http://host/worker.ign /dev/sda
```
Important
The --copy-network option only copies networking configuration found under /etc/NetworkManager/system-connections. In particular, it does not copy the system hostname.
Reboot into the installed system.

1.2.13.3.2. Disk partitioning

However, there are two cases where you might want to intervene to override the default partitioning when installing an OpenShift Container Platform node:

Create separate partitions: For greenfield installations on an empty disk, you might want to add separate storage to a partition. This is officially supported for making /var or a subdirectory of /var, such as /var/lib/etcd, a separate partition, but not both.
Important
Kubernetes supports only two filesystem partitions. If you add more than one partition to the original configuration, Kubernetes cannot monitor all of them.
Retain existing partitions: For a brownfield installation where you are reinstalling OpenShift Container Platform on an existing node and want to retain data partitions installed from your previous operating system, there are both boot arguments and options to coreos-installer that allow you to retain existing data partitions.

1.2.13.3.2.1. Creating a separate `/var` partition

OpenShift Container Platform supports the addition of a single partition to attach storage to either the /var partition or a subdirectory of /var. For example:

/var/lib/containers: Holds container-related content that can grow as more images and containers are added to a system.
/var/lib/etcd: Holds data that you might want to keep separate for purposes such as performance optimization of etcd storage.
/var: Holds data that you might want to keep separate for purposes such as auditing.

Procedure

Create a directory to hold the OpenShift Container Platform installation files:
```
$ mkdir $HOME/clusterconfig
```

Run openshift-install to create a set of files in the manifest and openshift subdirectories. Answer the system questions as you are prompted:

$ openshift-install create manifests --dir $HOME/clusterconfig
? SSH Public Key ...
$ ls $HOME/clusterconfig/openshift/
99_kubeadmin-password-secret.yaml
99_openshift-cluster-api_master-machines-0.yaml
99_openshift-cluster-api_master-machines-1.yaml
99_openshift-cluster-api_master-machines-2.yaml
...

Create a MachineConfig object and add it to a file in the openshift directory. For example, name the file 98-var-partition.yaml, change the disk device name to the name of the storage device on the worker systems, and set the storage size as appropriate. This example places the /var directory on a separate partition:
```
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
metadata:
  labels:
    machineconfiguration.openshift.io/role: worker
  name: 98-var-partition
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      disks:
      - device: /dev/<device_name> 1
        partitions:
        - label: var
          startMiB: <partition_start_offset> 2
          sizeMiB: <partition_size> 3
      filesystems:
        - device: /dev/disk/by-partlabel/var
          path: /var
          format: xfs
    systemd:
      units:
        - name: var.mount 4
          enabled: true
          contents: |
            [Unit]
            Before=local-fs.target
            [Mount]
            What=/dev/disk/by-partlabel/var
            Where=/var
            Options=defaults,prjquota 5
            [Install]
            WantedBy=local-fs.target
```
1
The storage device name of the disk that you want to partition.
2
When adding a data partition to the boot disk, a minimum value of 25000 mebibytes is recommended. The root file system is automatically resized to fill all available space up to the specified offset. If no value is specified, or if the specified value is smaller than the recommended minimum, the resulting root file system will be too small, and future reinstalls of RHCOS might overwrite the beginning of the data partition.
3
The size of the data partition in mebibytes.
4
The name of the mount unit must match the directory specified in the Where= directive. For example, for a filesystem mounted on /var/lib/containers, the unit must be named var-lib-containers.mount.
5
The prjquota mount option must be enabled for filesystems used for container storage.
Note
When creating a separate /var partition, you cannot use different instance types for worker nodes, if the different instance types do not have the same device name.

Run openshift-install again to create Ignition configs from a set of files in the manifest and openshift subdirectories:

$ openshift-install create ignition-configs --dir $HOME/clusterconfig
$ ls $HOME/clusterconfig/
auth  bootstrap.ign  master.ign  metadata.json  worker.ign

Now you can use the Ignition config files as input to the ISO or PXE manual installation procedures to install Red Hat Enterprise Linux CoreOS (RHCOS) systems.

1.2.13.3.2.2. Retaining existing partitions

Saved partitions might be partitions from an existing OpenShift Container Platform system that has data partitions that you want to keep. Here are a few tips:

If you save existing partitions, and those partitions do not leave enough space for RHCOS, installation will fail without damaging the saved partitions.
Identify the disk partitions you want to keep either by partition label or by number.

For an ISO installation

This example preserves any partition in which the partition label begins with data (data*):

# coreos-installer install --ignition-url http://10.0.2.2:8080/user.ign \
        --save-partlabel 'data*' /dev/sda

The following example illustrates running the coreos-installer in a way that preserves the sixth (6) partition on the disk:

# coreos-installer install --ignition-url http://10.0.2.2:8080/user.ign \
        --save-partindex 6 /dev/sda

This example preserves partitions 5 and higher:

# coreos-installer install --ignition-url http://10.0.2.2:8080/user.ign
        --save-partindex 5- /dev/sda

In the previous examples where partition saving is used, coreos-installer recreates the partition immediately.

For a PXE installation

This APPEND option preserves any partition in which the partition label begins with 'data' ('data*'):

coreos.inst.save_partlabel=data*

This APPEND option preserves partitions 5 and higher:

coreos.inst.save_partindex=5-

This APPEND option preserves partition 6:

coreos.inst.save_partindex=6

1.2.13.3.3. Identifying Ignition configs

When doing an RHCOS manual installation, there are two types of Ignition configs that you can provide, with different reasons for providing each one:

Permanent install Ignition config: Every manual RHCOS installation needs to pass one of the Ignition config files generated by openshift-installer, such as bootstrap.ign, master.ign and worker.ign, to carry out the installation.
Important
It is not recommended to modify these files.
For PXE installations, you pass the Ignition configs on the APPEND line using the coreos.inst.ignition_url= option. For ISO installations, after the ISO boots to the shell prompt, you identify the Ignition config on the coreos-installer command line with the --ignition-url= option. In both cases, only HTTP and HTTPS protocols are supported.
Live install Ignition config: This type must be created manually and should be avoided if possible, as it is not supported by Red Hat. With this method, the Ignition config passes to the live install medium, runs immediately upon booting, and performs setup tasks before and/or after the RHCOS system installs to disk. This method should only be used for performing tasks that must be performed once and not applied again later, such as with advanced partitioning that cannot be done using a machine config.
For PXE or ISO boots, you can create the Ignition config and APPEND the ignition.config.url= option to identify the location of the Ignition config. You also need to append ignition.firstboot ignition.platform.id=metal or the ignition.config.url option will be ignored.

1.2.13.3.3.1. Embedding an Ignition config in the RHCOS ISO

You can embed a live install Ignition config directly in an RHCOS ISO image. When the ISO image is booted, the embedded config will be applied automatically.

Procedure

Download the coreos-installer binary from the following image mirror page: https://mirror.openshift.com/pub/openshift-v4/clients/coreos-installer/latest/.
Retrieve the RHCOS ISO image and the Ignition config file, and copy them into an accessible directory, such as /mnt:
```
# cp rhcos-<version>-live.x86_64.iso bootstrap.ign /mnt/
# chmod 644 /mnt/rhcos-<version>-live.x86_64.iso
```
Run the following command to embed the Ignition config into the ISO:
```
# ./coreos-installer iso ignition embed -i /mnt/bootstrap.ign \
     /mnt/rhcos-<version>-live.x86_64.iso
```
You can now use that ISO to install RHCOS using the specified live install Ignition config.
Important
Using coreos-installer iso ignition embed to embed a file generated by openshift-installer, such as bootstrap.ign, master.ign and worker.ign, is unsupported and not recommended.

To show the contents of the embedded Ignition config and direct it into a file, run:

# ./coreos-installer iso ignition show /mnt/rhcos-<version>-live.x86_64.iso > mybootstrap.ign

# diff -s bootstrap.ign mybootstrap.ign

Example output

Files bootstrap.ign and mybootstrap.ign are identical

To remove the Ignition config and return the ISO to its pristine state so you can reuse it, run:
```
# ./coreos-installer iso ignition remove /mnt/rhcos-<version>-live.x86_64.iso
```
You can now embed another Ignition config into the ISO or use the ISO in its pristine state.

1.2.13.3.4. Advanced RHCOS installation reference

Routing and bonding options at RHCOS boot prompt

Important

When adding networking arguments, you must also add the rd.neednet=1 kernel argument.

The following table describes how to use ip=, nameserver=, and bond= kernel arguments for live ISO installs.

Note

Ordering is important when adding kernel arguments: ip=, nameserver=, and then bond=.

Routing and bonding options for ISO

Description	Examples
To configure an IP address, either use DHCP (`ip=dhcp`) or set an individual static IP address (`ip=<host_ip>`). Then identify the DNS server IP address (`nameserver=<dns_ip>`) on each node. This example sets: The node’s IP address to `10.10.10.2` The gateway address to `10.10.10.254` The netmask to `255.255.255.0` The hostname to `core0.example.com` The DNS server address to `4.4.4.41`	ip=10.10.10.2::10.10.10.254:255.255.255.0:core0.example.com:enp1s0:none nameserver=4.4.4.41
Specify multiple network interfaces by specifying multiple `ip=` entries.	ip=10.10.10.2::10.10.10.254:255.255.255.0:core0.example.com:enp1s0:none ip=10.10.10.3::10.10.10.254:255.255.255.0:core0.example.com:enp2s0:none
Optional: You can configure routes to additional networks by setting an `rd.route=` value. If the additional network gateway is different from the primary network gateway, the default gateway must be the primary network gateway.	To configure the default gateway: ip=::10.10.10.254:::: To configure the route for the additional network: rd.route=20.20.20.0/24:20.20.20.254:enp2s0
Disable DHCP on a single interface, such as when there are two or more network interfaces and only one interface is being used.	ip=10.10.10.2::10.10.10.254:255.255.255.0:core0.example.com:enp1s0:none ip=::::core0.example.com:enp2s0:none
You can combine DHCP and static IP configurations on systems with multiple network interfaces.	ip=enp1s0:dhcp ip=10.10.10.2::10.10.10.254:255.255.255.0:core0.example.com:enp2s0:none
Optional: You can configure VLANs on individual interfaces by using the `vlan=` parameter.	To configure a VLAN on a network interface and use a static IP address: ip=10.10.10.2::10.10.10.254:255.255.255.0:core0.example.com:enp2s0.100:none vlan=enp2s0.100:enp2s0 To configure a VLAN on a network interface and to use DHCP: ip=enp2s0.100:dhcp vlan=enp2s0.100:enp2s0
You can provide multiple DNS servers by adding a `nameserver=` entry for each server.	nameserver=1.1.1.1 nameserver=8.8.8.8
Optional: Bonding multiple network interfaces to a single interface is supported using the `bond=` option. In these two examples: The syntax for configuring a bonded interface is: `bond=name[:network_interfaces][:options]` name is the bonding device name (`bond0`), network_interfaces represents a comma-separated list of physical (ethernet) interfaces (`em1,em2`), and options is a comma-separated list of bonding options. Enter `modinfo bonding` to see available options. When you create a bonded interface using `bond=`, you must specify how the IP address is assigned and other information for the bonded interface.	To configure the bonded interface to use DHCP, set the bond’s IP address to `dhcp`. For example: bond=bond0:em1,em2:mode=active-backup ip=bond0:dhcp To configure the bonded interface to use a static IP address, enter the specific IP address you want and related information. For example: bond=bond0:em1,em2:mode=active-backup ip=10.10.10.2::10.10.10.254:255.255.255.0:core0.example.com:bond0:none
Optional: You can configure VLANs on bonded interfaces by using the `vlan=` parameter.	To configure the bonded interface with a VLAN and to use DHCP: ip=bond0.100:dhcp bond=bond0:em1,em2:mode=active-backup vlan=bond0.100:bond0 To configure the bonded interface with a VLAN and to use a static IP address: ip=10.10.10.2::10.10.10.254:255.255.255.0:core0.example.com:bond0.100:none bond=bond0:em1,em2:mode=active-backup vlan=bond0.100:bond0
Optional: Network teaming can be used as an alternative to bonding by using the `team=` parameter. In this example: The syntax for configuring a team interface is: `team=name[:network_interfaces]` name is the team device name (`team0`) and network_interfaces represents a comma-separated list of physical (ethernet) interfaces (`em1, em2`). Note Teaming is planned to be deprecated when RHCOS switches to an upcoming version of RHEL. For more information, see this Red Hat Knowledgebase Article.	To configure a network team: team=team0:em1,em2 ip=team0:dhcp

`coreos.inst` boot options for ISO or PXE install

While you can pass most standard installation boot arguments to the live installer, there are several arguments that are specific to the RHCOS live installer.

For ISO, these options can be added by interrupting the RHCOS installer.
For PXE or iPXE, these options must be added to the APPEND line before starting the PXE kernel. You cannot interrupt a live PXE install.

The following table shows the RHCOS live installer boot options for ISO and PXE installs.

Table 1.26. coreos.inst boot options
Argument	Description
`coreos.inst.install_dev`	Required. The block device on the system to install to. It is recommended to use the full path, such as `/dev/sda`, although `sda` is allowed.
`coreos.inst.ignition_url`	Optional: The URL of the Ignition config to embed into the installed system. If no URL is specified, no Ignition config is embedded.
`coreos.inst.save_partlabel`	Optional: Comma-separated labels of partitions to preserve during the install. Glob-style wildcards are permitted. The specified partitions do not need to exist.
`coreos.inst.save_partindex`	Optional: Comma-separated indexes of partitions to preserve during the install. Ranges `m`-`n` are permitted, and either `m` or `n` can be omitted. The specified partitions do not need to exist.
`coreos.inst.insecure`	Optional: Permits the OS image that is specified by `coreos.inst.image_url` to be unsigned.
`coreos.inst.image_url`	Optional: Download and install the specified RHCOS image. This argument should not be used in production environments and is intended for debugging purposes only. While this argument can be used to install a version of RHCOS that does not match the live media, it is recommended that you instead use the media that matches the version you want to install. If you are using `coreos.inst.image_url`, you must also use `coreos.inst.insecure`. This is because the bare-metal media are not GPG-signed for OpenShift Container Platform. Only HTTP and HTTPS protocols are supported.
`coreos.inst.skip_reboot`	Optional: The system will not reboot after installing. Once the install finishes, you will receive a prompt that allows you to inspect what is happening during installation. This argument should not be used in production environments and is intended for debugging purposes only.
`coreos.inst.platform_id`	Optional: The Ignition platform ID of the platform the RHCOS image is being installed on. Default is `metal`. This option determines whether or not to request an Ignition config from the cloud provider, such as VMware. For example: `coreos.inst.platform_id=vmware`.
`ignition.config.url`	Optional: The URL of the Ignition config for the live boot. For example, this can be used to customize how `coreos-installer` is invoked, or to run code before or after the installation. This is different from `coreos.inst.ignition_url`, which is the Ignition config for the installed system.

`coreos-installer` options for ISO install

The following table shows the options and subcommands you can pass to the coreos-installer command from a shell prompt during a live install.

Table 1.27. coreos-installer command-line options, arguments, and subcommands
Command-line options
Option	Description
`-u`, `--image-url <url>`	Specify the image URL manually.
`-f`, `--image-file <path>`	Specify a local image file manually.
`-i,` `--ignition-file <path>`	Embed an Ignition config from a file.
`-I`, `--ignition-url <URL>`	Embed an Ignition config from a URL.
`--ignition-hash <digest>`	Digest `type-value` of the Ignition config.
`-p`, `--platform <name>`	Override the Ignition platform ID.
`--append-karg <arg>…`	Append the default kernel argument.
`--delete-karg <arg>…`	Delete the default kernel argument.
`-n`, `--copy-network`	Copy the network configuration from the install environment. Important The `--copy-network` option only copies networking configuration found under `/etc/NetworkManager/system-connections`. In particular, it does not copy the system hostname.
`--network-dir <path>`	For use with `-n`. Default is `/etc/NetworkManager/system-connections/`.
`--save-partlabel <lx>..`	Save partitions with this label glob.
`--save-partindex <id>…`	Save partitions with this number or range.
`--offline`	Force offline installation.
`--insecure`	Skip signature verification.
`--insecure-ignition`	Allow Ignition URL without HTTPS or hash.
`--architecture <name>`	Target CPU architecture. Default is `x86_64`.
`--preserve-on-error`	Do not clear partition table on error.
`-h`, `--help`	Print help information.
Command-line argument
Argument	Description
`<device>`	The destination device.
coreos-installer embedded Ignition commands
Command	Description
`$ coreos-installer iso ignition embed <options> --ignition-file <file_path> <ISO_image>`	Embed an Ignition config in an ISO image.
`coreos-installer iso ignition show <options> <ISO_image>`	Show the embedded Ignition config from an ISO image.
`coreos-installer iso ignition remove <options> <ISO_image>`	Remove the embedded Ignition config from an ISO image.
coreos-installer ISO Ignition options
Option	Description
`-f`, `--force`	Overwrite an existing Ignition config.
`-i`, `--ignition-file <path>`	The Ignition config to be used. Default is `stdin`.
`-o`, `--output <path>`	Write the ISO to a new output file.
`-h`, `--help`	Print help information.
coreos-installer PXE Ignition commands
Command	Description
Note that not all of these options are accepted by all subcommands.
`coreos-installer pxe ignition wrap <options>`	Wrap an Ignition config in an image.
`coreos-installer pxe ignition unwrap <options> <image_name>`	Show the wrapped Ignition config in an image.
`coreos-installer pxe ignition unwrap <options> <initrd_name>`	Show the wrapped Ignition config in an `initrd` image.
coreos-installer PXE Ignition options
Option	Description
`-i`, `--ignition-file <path>`	The Ignition config to be used. Default is `stdin`.
`-o,` `--output <path>`	Write the ISO to a new output file.
`-h`, `--help`	Print help information.

1.2.14. Creating the cluster

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
```
1
For <installation_directory>, specify the path to the directory that you stored the installation files in.
2
To view different installation details, specify warn, debug, or error instead of info.
Example output
```
INFO Waiting up to 30m0s for the Kubernetes API at https://api.test.example.com:6443...
INFO API v1.19.0 up
INFO Waiting up to 30m0s for bootstrapping to complete...
INFO It is now safe to remove the bootstrap resources
```
The command succeeds when the Kubernetes API server signals that it has been bootstrapped on the control plane machines.
After bootstrap process is complete, remove the bootstrap machine from the load balancer.
Important
You must remove the bootstrap machine from the load balancer at this point. You can also remove or reformat the machine itself.

1.2.15. Logging in to the cluster by using the CLI

Prerequisites

You deployed an OpenShift Container Platform cluster.
You installed the oc CLI.

Procedure

Export the kubeadmin credentials:
```
$ export KUBECONFIG=<installation_directory>/auth/kubeconfig 1
```
1
For <installation_directory>, specify the path to the directory that you stored the installation files in.
Verify you can run oc commands successfully using the exported configuration:
```
$ oc whoami
```
Example output
```
system:admin
```

1.2.16. Approving the certificate signing requests for your machines

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  v1.19.0
master-1  Ready     master  63m  v1.19.0
master-2  Ready     master  64m  v1.19.0
```
The output lists all of the machines that you created.
Note
The preceding output might not include the compute nodes, also known as worker nodes, until some CSRs are approved.

Review the pending CSRs and ensure that you see the client requests with the Pending or Approved 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:
Note
Because 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.
Note
For clusters running on platforms that are not machine API enabled, such as bare metal and other user-provisioned infrastructure, you must implement a method of automatically approving the kubelet serving certificate requests (CSRs). If a request is not approved, then the oc exec, oc rsh, and oc logs commands cannot succeed, because a serving certificate is required when the API server connects to the kubelet. Any operation that contacts the Kubelet endpoint requires this certificate approval to be in place. The method must watch for new CSRs, confirm that the CSR was submitted by the node-bootstrapper service account in the system:node or system:admin groups, and confirm the identity of the node.
- To approve them individually, run the following command for each valid CSR:
```
$ oc adm certificate approve <csr_name> 1
```
  1
  <csr_name> is the name of a CSR from the list of current CSRs.
- To approve all pending CSRs, run the following command:
```
$ oc get csr -o go-template='{{range .items}}{{if not .status}}{{.metadata.name}}{{"\n"}}{{end}}{{end}}' | xargs --no-run-if-empty oc adm certificate approve
```
  Note
  Some Operators might not become available until some CSRs are approved.

Now that your client requests are approved, you must review the server requests for each machine that you added to the cluster:

$ oc get csr

Example output

NAME        AGE     REQUESTOR                                                                   CONDITION
csr-bfd72   5m26s   system:node:ip-10-0-50-126.us-east-2.compute.internal                       Pending
csr-c57lv   5m26s   system:node:ip-10-0-95-157.us-east-2.compute.internal                       Pending
...

If the remaining CSRs are not approved, and are in the Pending status, approve the CSRs for your cluster machines:
- To approve them individually, run the following command for each valid CSR:
```
$ oc adm certificate approve <csr_name> 1
```
  1
  <csr_name> is the name of a CSR from the list of current CSRs.
- To approve all pending CSRs, run the following command:
```
$ oc get csr -o go-template='{{range .items}}{{if not .status}}{{.metadata.name}}{{"\n"}}{{end}}{{end}}' | xargs oc adm certificate approve
```

After all client and server CSRs have been approved, the machines have the Ready status. Verify this by running the following command:

$ oc get nodes

Example output

NAME      STATUS    ROLES   AGE  VERSION
master-0  Ready     master  73m  v1.20.0
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

Note

It 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.

1.2.17. 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                             4.6.0   True        False         False      3h56m
cloud-credential                           4.6.0   True        False         False      29h
cluster-autoscaler                         4.6.0   True        False         False      29h
config-operator                            4.6.0   True        False         False      6h39m
console                                    4.6.0   True        False         False      3h59m
csi-snapshot-controller                    4.6.0   True        False         False      4h12m
dns                                        4.6.0   True        False         False      4h15m
etcd                                       4.6.0   True        False         False      29h
image-registry                             4.6.0   True        False         False      3h59m
ingress                                    4.6.0   True        False         False      4h30m
insights                                   4.6.0   True        False         False      29h
kube-apiserver                             4.6.0   True        False         False      29h
kube-controller-manager                    4.6.0   True        False         False      29h
kube-scheduler                             4.6.0   True        False         False      29h
kube-storage-version-migrator              4.6.0   True        False         False      4h2m
machine-api                                4.6.0   True        False         False      29h
machine-approver                           4.6.0   True        False         False      6h34m
machine-config                             4.6.0   True        False         False      3h56m
marketplace                                4.6.0   True        False         False      4h2m
monitoring                                 4.6.0   True        False         False      6h31m
network                                    4.6.0   True        False         False      29h
node-tuning                                4.6.0   True        False         False      4h30m
openshift-apiserver                        4.6.0   True        False         False      3h56m
openshift-controller-manager               4.6.0   True        False         False      4h36m
openshift-samples                          4.6.0   True        False         False      4h30m
operator-lifecycle-manager                 4.6.0   True        False         False      29h
operator-lifecycle-manager-catalog         4.6.0   True        False         False      29h
operator-lifecycle-manager-packageserver   4.6.0   True        False         False      3h59m
service-ca                                 4.6.0   True        False         False      29h
storage                                    4.6.0   True        False         False      4h30m

Configure the Operators that are not available.

1.2.17.1. Image registry removed during installation

After installation, you must edit the Image Registry Operator configuration to switch the managementState from Removed to Managed.

Note

The Prometheus console provides an ImageRegistryRemoved alert, for example:

1.2.17.2. Image registry storage configuration

Additional instructions are provided for allowing the image registry to use block storage types by using the Recreate rollout strategy during upgrades.

1.2.17.3. Configuring block registry storage

To allow the image registry to use block storage types during upgrades as a cluster administrator, you can use the Recreate rollout strategy.

Important

Procedure

To set the image registry storage as a block storage type, patch the registry so that it uses the Recreate rollout strategy and runs with only one (1) replica:
```
$ oc patch config.imageregistry.operator.openshift.io/cluster --type=merge -p '{"spec":{"rolloutStrategy":"Recreate","replicas":1}}'
```
Provision the PV for the block storage device, and create a PVC for that volume. The requested block volume uses the ReadWriteOnce (RWO) access mode.
Edit the registry configuration so that it references the correct PVC.

1.2.18. 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                             4.6.0   True        False         False      3h56m
cloud-credential                           4.6.0   True        False         False      29h
cluster-autoscaler                         4.6.0   True        False         False      29h
config-operator                            4.6.0   True        False         False      6h39m
console                                    4.6.0   True        False         False      3h59m
csi-snapshot-controller                    4.6.0   True        False         False      4h12m
dns                                        4.6.0   True        False         False      4h15m
etcd                                       4.6.0   True        False         False      29h
image-registry                             4.6.0   True        False         False      3h59m
ingress                                    4.6.0   True        False         False      4h30m
insights                                   4.6.0   True        False         False      29h
kube-apiserver                             4.6.0   True        False         False      29h
kube-controller-manager                    4.6.0   True        False         False      29h
kube-scheduler                             4.6.0   True        False         False      29h
kube-storage-version-migrator              4.6.0   True        False         False      4h2m
machine-api                                4.6.0   True        False         False      29h
machine-approver                           4.6.0   True        False         False      6h34m
machine-config                             4.6.0   True        False         False      3h56m
marketplace                                4.6.0   True        False         False      4h2m
monitoring                                 4.6.0   True        False         False      6h31m
network                                    4.6.0   True        False         False      29h
node-tuning                                4.6.0   True        False         False      4h30m
openshift-apiserver                        4.6.0   True        False         False      3h56m
openshift-controller-manager               4.6.0   True        False         False      4h36m
openshift-samples                          4.6.0   True        False         False      4h30m
operator-lifecycle-manager                 4.6.0   True        False         False      29h
operator-lifecycle-manager-catalog         4.6.0   True        False         False      29h
operator-lifecycle-manager-packageserver   4.6.0   True        False         False      3h59m
service-ca                                 4.6.0   True        False         False      29h
storage                                    4.6.0   True        False         False      4h30m

Alternatively, the following command notifies you when all of the clusters are available. It also retrieves and displays credentials:

$ ./openshift-install --dir <installation_directory> wait-for install-complete 1

1: For <installation_directory>, specify the path to the directory that you stored the installation files in.

Example output

INFO Waiting up to 30m0s for the cluster to initialize...

The command succeeds when the Cluster Version Operator finishes deploying the OpenShift Container Platform cluster from Kubernetes API server.

Important

The Ignition config files that the installation program generates contain certificates that expire after 24 hours, which are then renewed at that time. If the cluster is shut down before renewing the certificates and the cluster is later restarted after the 24 hours have elapsed, the cluster automatically recovers the expired certificates. The exception is that you must manually approve the pending node-bootstrapper certificate signing requests (CSRs) to recover kubelet certificates. See the documentation for Recovering from expired control plane certificates for more information.
It is recommended that you use Ignition config files within 12 hours after they are generated because the 24-hour certificate rotates from 16 to 22 hours after the cluster is installed. By using the Ignition config files within 12 hours, you can avoid installation failure if the certificate update runs during installation.

Confirm that the Kubernetes API server is communicating with the pods.

To view a list of all pods, use the following command:

$ oc get pods --all-namespaces

Example output

NAMESPACE                         NAME                                            READY   STATUS      RESTARTS   AGE
openshift-apiserver-operator      openshift-apiserver-operator-85cb746d55-zqhs8   1/1     Running     1          9m
openshift-apiserver               apiserver-67b9g                                 1/1     Running     0          3m
openshift-apiserver               apiserver-ljcmx                                 1/1     Running     0          1m
openshift-apiserver               apiserver-z25h4                                 1/1     Running     0          2m
openshift-authentication-operator authentication-operator-69d5d8bf84-vh2n8        1/1     Running     0          5m
...

View the logs for a pod that is listed in the output of the previous command by using the following command:
```
$ oc logs <pod_name> -n <namespace> 1
```
1
Specify the pod name and namespace, as shown in the output of the previous command.
If the pod logs display, the Kubernetes API server can communicate with the cluster machines.

1.2.19. Telemetry access for OpenShift Container Platform

Additional resources

See About remote health monitoring for more information about the Telemetry service

1.2.20. Next steps

Customize your cluster.
If necessary, you can opt out of remote health reporting.
Set up your registry and configure registry storage.

1.3. Installing a cluster on bare metal in a restricted network

In OpenShift Container Platform version 4.6, you can install a cluster on bare metal infrastructure that you provision in a restricted network.

Important

1.3.1. Prerequisites

Create a registry on your mirror host and obtain the imageContentSources data for your version of OpenShift Container Platform.
Important
Because the installation media is on the mirror host, you can use that computer to complete all installation steps.
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.
Note
Be sure to also review this site list if you are configuring a proxy.

1.3.2. About installations in restricted networks

In OpenShift Container Platform 4.6, you can perform an installation that does not require an active connection to the Internet to obtain software components. Restricted network installations can be completed using installer-provisioned infrastructure or user-provisioned infrastructure, depending on the cloud platform to which you are installing the cluster.

If you choose to perform a restricted network installation on a cloud platform, you still require access to its cloud APIs. Some cloud functions, like Amazon Web Service’s Route 53 DNS and IAM services, require internet access. Depending on your network, you might require less Internet access for an installation on bare metal hardware or on VMware vSphere.

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.

Important

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.

1.3.2.1. Additional limits

Clusters in restricted networks have the following additional limitations and restrictions:

The ClusterVersion status includes an Unable 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.

1.3.3. Internet access for OpenShift Container Platform

In OpenShift Container Platform 4.6, you require access to the Internet to obtain the images that are necessary to install your cluster.

You must have Internet access to:

Access OpenShift Cluster Manager 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.

Important

1.3.4. 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.

1.3.4.1. 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. If you are running a three-node cluster, running zero compute machines is supported. Running one compute machine is not supported.

Note

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.

Important

To maintain high availability of your cluster, use separate physical hosts for these cluster machines.

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.

1.3.4.2. Network connectivity requirements

1.3.4.3. Minimum resource requirements

Each cluster machine must meet the following minimum requirements:

Machine	Operating System	CPU ^[1]	RAM	Storage	IOPS ^[2]
Bootstrap	RHCOS	4	16 GB	100 GB	300
Control plane	RHCOS	4	16 GB	100 GB	300
Compute	RHCOS or RHEL 7.9	2	8 GB	100 GB	300

One CPU is equivalent to one 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 = CPUs.
OpenShift Container Platform and Kubernetes are sensitive to disk performance, and faster storage is recommended, particularly for etcd on the control plane nodes which require a 10 ms p99 fsync duration. Note that on many cloud platforms, storage size and IOPS scale together, so you might need to over-allocate storage volume to obtain sufficient performance.

1.3.4.4. Certificate signing requests management

1.3.5. 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.

1.3.5.1. 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.

Table 1.28. All machines to all machines
Protocol	Port	Description
ICMP	N/A	Network reachability tests
TCP	`1936`	Metrics
	`9000`-`9999`	Host level services, including the node exporter on ports `9100`-`9101` and the Cluster Version Operator on port `9099`.
	`10250`-`10259`	The default ports that Kubernetes reserves
	`10256`	openshift-sdn
UDP	`4789`	VXLAN and Geneve
	`6081`	VXLAN and Geneve
	`9000`-`9999`	Host level services, including the node exporter on ports `9100`-`9101`.
TCP/UDP	`30000`-`32767`	Kubernetes node port

Table 1.29. All machines to control plane
Protocol	Port	Description
TCP	`6443`	Kubernetes API

Table 1.30. Control plane machines to control plane machines
Protocol	Port	Description
TCP	`2379`-`2380`	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.

Important

Do not configure session persistence for an API load balancer.

Configure the following ports on both the front and back of the load balancers:

Table 1.31. 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

Note

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 1.32. 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

Tip

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.

Note

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.

NTP configuration

If a DHCP server provides NTP server information, the chrony time service on the Red Hat Enterprise Linux CoreOS (RHCOS) machines read the information and can sync the clock with the NTP servers.

Additional resources

Configuring chrony time service

1.3.5.2. User-provisioned DNS requirements

Table 1.33. Required DNS records
Component	Record	Description
Kubernetes API	`api.<cluster_name>.<base_domain>.`	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.
Kubernetes API	`api-int.<cluster_name>.<base_domain>.`	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	`*.apps.<cluster_name>.<base_domain>.`	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	`bootstrap.<cluster_name>.<base_domain>.`	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	`<master><n>.<cluster_name>.<base_domain>.`	DNS A/AAAA or CNAME records and DNS PTR records to identify each machine for the control plane nodes (also known as the master nodes). These records must be resolvable by the nodes within the cluster.
Worker hosts	`<worker><n>.<cluster_name>.<base_domain>.`	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.

Tip

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.

Example 1.5. 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 1.6. 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

1.3.6. Generating an SSH private key and adding it to the agent

Note

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.

Note

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.
Note
If 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 the ed25519 algorithm. Instead, create a key that uses the rsa or ecdsa algorithm.
Start the ssh-agent process as a background task:
```
$ eval "$(ssh-agent -s)"
```
Example output
```
Agent pid 31874
```
Note
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

Next steps

When you install OpenShift Container Platform, provide the SSH public key to the installation program. If you install a cluster on infrastructure that you provision, you must provide this key to your cluster’s machines.

1.3.7. 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.
Obtain the imageContentSources section from the output of the command to mirror the repository.
Obtain the contents of the certificate for your mirror registry.

Procedure

Create an installation directory to store your required installation assets in:
```
$ mkdir <installation_directory>
```
Important
You 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>.
Note
You must name this configuration file install-config.yaml.
- Unless you use a registry that RHCOS trusts by default, such as docker.io, you must provide the contents of the certificate for your mirror repository in the additionalTrustBundle section. In most cases, you must provide the certificate for your mirror.
- You must include the imageContentSources section from the output of the command to mirror the repository.
Back up the install-config.yaml file so that you can use it to install multiple clusters.
Important
The install-config.yaml file is consumed during the next step of the installation process. You must back it up now.

1.3.7.1. Installation configuration parameters

Note

After installation, you cannot modify these parameters in the install-config.yaml file.

Important

1.3.7.1.1. Required configuration parameters

Required installation configuration parameters are described in the following table:

Table 1.34. Required parameters
Parameter	Description	Values
`apiVersion`	The API version for the `install-config.yaml` content. The current version is `v1`. The installer may also support older API versions.	String
`baseDomain`	The base domain of your cloud provider. The base domain is used to create routes to your OpenShift Container Platform cluster components. The full DNS name for your cluster is a combination of the `baseDomain` and `metadata.name` parameter values that uses the `<metadata.name>.<baseDomain>` format.	A fully-qualified domain or subdomain name, such as `example.com`.
`metadata`	Kubernetes resource `ObjectMeta`, from which only the `name` parameter is consumed.	Object
`metadata.name`	The name of the cluster. DNS records for the cluster are all subdomains of `{{.metadata.name}}.{{.baseDomain}}`.	String of lowercase letters, hyphens (`-`), and periods (`.`), such as `dev`.
`platform`	The configuration for the specific platform upon which to perform the installation: `aws`, `baremetal`, `azure`, `openstack`, `ovirt`, `vsphere`. For additional information about `platform.<platform>` parameters, consult the following table for your specific platform.	Object
`pullSecret`	Get a pull secret from the Red Hat OpenShift Cluster Manager to authenticate downloading container images for OpenShift Container Platform components from services such as Quay.io.	{ "auths":{ "cloud.openshift.com":{ "auth":"b3Blb=", "email":"you@example.com" }, "quay.io":{ "auth":"b3Blb=", "email":"you@example.com" } } }

1.3.7.1.2. Network configuration parameters

Only IPv4 addresses are supported.

Table 1.35. Network parameters
Parameter	Description	Values
`networking`	The configuration for the cluster network.	Object Note You cannot modify parameters specified by the `networking` object after installation.
`networking.networkType`	The cluster network provider Container Network Interface (CNI) plug-in to install.	Either `OpenShiftSDN` or `OVNKubernetes`. The default value is `OpenShiftSDN`.
`networking.clusterNetwork`	The IP address blocks for pods. The default value is `10.128.0.0/14` with a host prefix of `/23`. If you specify multiple IP address blocks, the blocks must not overlap.	An array of objects. For example: networking: clusterNetwork: - cidr: 10.128.0.0/14 hostPrefix: 23
`networking.clusterNetwork.cidr`	Required if you use `networking.clusterNetwork`. An IP address block. An IPv4 network.	An IP address block in Classless Inter-Domain Routing (CIDR) notation. The prefix length for an IPv4 block is between `0` and `32`.
`networking.clusterNetwork.hostPrefix`	The subnet prefix length to assign to each individual node. For example, if `hostPrefix` is set to `23` then each node is assigned a `/23` subnet out of the given `cidr`. A `hostPrefix` value of `23` provides 510 (2^(32 - 23) - 2) pod IP addresses.	A subnet prefix. The default value is `23`.
`networking.serviceNetwork`	The IP address block for services. The default value is `172.30.0.0/16`. The OpenShift SDN and OVN-Kubernetes network providers support only a single IP address block for the service network.	An array with an IP address block in CIDR format. For example: networking: serviceNetwork: - 172.30.0.0/16
`networking.machineNetwork`	The IP address blocks for machines. If you specify multiple IP address blocks, the blocks must not overlap.	An array of objects. For example: networking: machineNetwork: - cidr: 10.0.0.0/16
`networking.machineNetwork.cidr`	Required if you use `networking.machineNetwork`. An IP address block. The default value is `10.0.0.0/16` for all platforms other than libvirt. For libvirt, the default value is `192.168.126.0/24`.	An IP network block in CIDR notation. For example, `10.0.0.0/16`. Note Set the `networking.machineNetwork` to match the CIDR that the preferred NIC resides in.

1.3.7.1.3. Optional configuration parameters

Optional installation configuration parameters are described in the following table:

Table 1.36. Optional parameters
Parameter	Description	Values
`additionalTrustBundle`	A PEM-encoded X.509 certificate bundle that is added to the nodes' trusted certificate store. This trust bundle may also be used when a proxy has been configured.	String
`compute`	The configuration for the machines that comprise the compute nodes.	Array of machine-pool objects. For details, see the following "Machine-pool" table.
`compute.architecture`	Determines the instruction set architecture of the machines in the pool. Currently, heteregeneous clusters are not supported, so all pools must specify the same architecture. Valid values are `amd64` (the default).	String
`compute.hyperthreading`	Whether to enable or disable simultaneous multithreading, or `hyperthreading`, on compute machines. By default, simultaneous multithreading is enabled to increase the performance of your machines' cores. Important If you disable simultaneous multithreading, ensure that your capacity planning accounts for the dramatically decreased machine performance.	`Enabled` or `Disabled`
`compute.name`	Required if you use `compute`. The name of the machine pool.	`worker`
`compute.platform`	Required if you use `compute`. Use this parameter to specify the cloud provider to host the worker machines. This parameter value must match the `controlPlane.platform` parameter value.	`aws`, `azure`, `gcp`, `openstack`, `ovirt`, `vsphere`, or `{}`
`compute.replicas`	The number of compute machines, which are also known as worker machines, to provision.	A positive integer greater than or equal to `2`. The default value is `3`.
`controlPlane`	The configuration for the machines that comprise the control plane.	Array of `MachinePool` objects. For details, see the following "Machine-pool" table.
`controlPlane.architecture`	Determines the instruction set architecture of the machines in the pool. Currently, heterogeneous clusters are not supported, so all pools must specify the same architecture. Valid values are `amd64` (the default).	String
`controlPlane.hyperthreading`	Whether to enable or disable simultaneous multithreading, or `hyperthreading`, on control plane machines. By default, simultaneous multithreading is enabled to increase the performance of your machines' cores. Important If you disable simultaneous multithreading, ensure that your capacity planning accounts for the dramatically decreased machine performance.	`Enabled` or `Disabled`
`controlPlane.name`	Required if you use `controlPlane`. The name of the machine pool.	`master`
`controlPlane.platform`	Required if you use `controlPlane`. Use this parameter to specify the cloud provider that hosts the control plane machines. This parameter value must match the `compute.platform` parameter value.	`aws`, `azure`, `gcp`, `openstack`, `ovirt`, `vsphere`, or `{}`
`controlPlane.replicas`	The number of control plane machines to provision.	The only supported value is `3`, which is the default value.
`credentialsMode`	The Cloud Credential Operator (CCO) mode. If no mode is specified, the CCO dynamically tries to determine the capabilities of the provided credentials, with a preference for mint mode on the platforms where multiple modes are supported. Note Not all CCO modes are supported for all cloud providers. For more information on CCO modes, see the Cloud Credential Operator entry in the Red Hat Operators reference content.	`Mint`, `Passthrough`, `Manual`, or an empty string (`""`).
`fips`	Enable or disable FIPS mode. The default is `false` (disabled). 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. Important The use of FIPS Validated / Modules in Process cryptographic libraries is only supported on OpenShift Container Platform deployments on the `x86_64` architecture. Note If you are using Azure File storage, you cannot enable FIPS mode.	`false` or `true`
`imageContentSources`	Sources and repositories for the release-image content.	Array of objects. Includes a `source` and, optionally, `mirrors`, as described in the following rows of this table.
`imageContentSources.source`	Required if you use `imageContentSources`. Specify the repository that users refer to, for example, in image pull specifications.	String
`imageContentSources.mirrors`	Specify one or more repositories that may also contain the same images.	Array of strings
`publish`	How to publish or expose the user-facing endpoints of your cluster, such as the Kubernetes API, OpenShift routes.	`Internal` or `External`. The default value is `External`. Setting this field to `Internal` is not supported on non-cloud platforms. Important If the value of the field is set to `Internal`, the cluster will become non-functional. For more information, refer to BZ#1953035.
`sshKey`	The SSH key or keys to authenticate access your cluster machines. Note For production OpenShift Container Platform clusters on which you want to perform installation debugging or disaster recovery, specify an SSH key that your `ssh-agent` process uses.	One or more keys. For example: sshKey: <key1> <key2> <key3>

1.3.7.2. Sample install-config.yaml file for bare metal

You can customize the install-config.yaml file to specify more details about your OpenShift Container Platform cluster’s platform or modify the values of the required parameters.

apiVersion: v1
baseDomain: example.com 1
compute: 2
- hyperthreading: Enabled 3
  name: worker
  replicas: 0 4
controlPlane: 5
  hyperthreading: Enabled 6
  name: master
  replicas: 3 7
metadata:
  name: test 8
networking:
  clusterNetwork:
  - cidr: 10.128.0.0/14 9
    hostPrefix: 23 10
  networkType: 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: quay.io/openshift-release-dev/ocp-v4.0-art-dev

1: The base domain of the cluster. All DNS records must be sub-domains of this base and include the cluster name.
2 5: The controlPlane section is a single mapping, but the compute section is a sequence of mappings. To meet the requirements of the different data structures, the first line of the compute section must begin with a hyphen, -, and the first line of the controlPlane section must not. 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 to Disabled. If you disable SMT, you must disable it in all cluster machines; this includes both control plane and compute machines.
Note
Simultaneous multithreading (SMT) is enabled by default. If SMT is not enabled in your BIOS settings, the hyperthreading parameter has no effect.
Important
If you disable hyperthreading, whether in the BIOS or in the install-config.yaml, ensure that your capacity planning accounts for the dramatically decreased machine performance.
4: You must set the value of the replicas parameter to 0. 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.
Note
Class E CIDR range is reserved for a future use. To use the Class E CIDR range, you must ensure your networking environment accepts the IP addresses within the Class E CIDR range.
10: The subnet prefix length to assign to each individual node. For example, if hostPrefix is set to 23, then each node is assigned a /23 subnet out of the given cidr, 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. This block must not overlap with existing physical networks. If you need to access the services from an external network, configure load balancers and routers to manage the traffic.
12: You must set the platform to none. You cannot provide additional platform configuration variables for your platform.
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.
Important
The use of FIPS Validated / Modules in Process cryptographic libraries is only supported on OpenShift Container Platform deployments on the x86_64 architecture.
14: For <local_registry>, specify the registry domain name, and optionally the port, that your mirror registry uses to serve content. For example registry.example.com or registry.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).
Note
For 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.

1.3.7.3. Configuring the cluster-wide proxy during installation

Note

Prerequisites

You have an existing install-config.yaml file.
You reviewed the sites that your cluster requires access to and determined whether any of them need to bypass the proxy. By default, all cluster egress traffic is proxied, including calls to hosting cloud provider APIs. You added sites to the Proxy object’s spec.noProxy field to bypass the proxy if necessary.
Note
The Proxy object status.noProxy field is populated with the values of the networking.machineNetwork[].cidr, networking.clusterNetwork[].cidr, and networking.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 object status.noProxy field is also populated with the instance metadata endpoint (169.254.169.254).

Procedure

Edit your install-config.yaml file and add the proxy settings. For example:
```
apiVersion: v1
baseDomain: my.domain.com
proxy:
  httpProxy: http://<username>:<pswd>@<ip>:<port> 1
  httpsProxy: https://<username>:<pswd>@<ip>:<port> 2
  noProxy: example.com 3
additionalTrustBundle: | 4
    -----BEGIN CERTIFICATE-----
    <MY_TRUSTED_CA_CERT>
    -----END CERTIFICATE-----
...
```
1
A proxy URL to use for creating HTTP connections outside the cluster. The URL scheme must be http.
2
A proxy URL to use for creating HTTPS connections outside the cluster.
3
A comma-separated list of destination domain names, IP addresses, or other network CIDRs to exclude from proxying. Preface a domain with . to match subdomains only. For example, .y.com matches x.y.com, but not y.com. Use * to bypass the proxy for all destinations.
4
If provided, the installation program generates a config map that is named user-ca-bundle in the openshift-config namespace to hold the additional CA certificates. If you provide additionalTrustBundle and at least one proxy setting, the Proxy object is configured to reference the user-ca-bundle config map in the trustedCA field. The Cluster Network Operator then creates a trusted-ca-bundle config map that merges the contents specified for the trustedCA parameter with the RHCOS trust bundle. The additionalTrustBundle field is required unless the proxy’s identity certificate is signed by an authority from the RHCOS trust bundle.
Note
The installation program does not support the proxy readinessEndpoints field.
Save the file and reference it when installing OpenShift Container Platform.

Note

Only the Proxy object named cluster is supported, and no additional proxies can be created.

1.3.8. Configuring a three-node cluster

Procedure

Edit the install-config.yaml file to set the number of compute replicas, which are also known as worker replicas, to 0, as shown in the following compute stanza:
```
compute:
- name: worker
  platform: {}
  replicas: 0
```

1.3.9. Creating the Kubernetes manifest and Ignition config files

The installation configuration file transforms into the Kubernetes manifests. The manifests wrap into the Ignition configuration files, which are later used to create the cluster.

Important

The Ignition config files that the installation program generates contain certificates that expire after 24 hours, which are then renewed at that time. If the cluster is shut down before renewing the certificates and the cluster is later restarted after the 24 hours have elapsed, the cluster automatically recovers the expired certificates. The exception is that you must manually approve the pending node-bootstrapper certificate signing requests (CSRs) to recover kubelet certificates. See the documentation for Recovering from expired control plane certificates for more information.
It is recommended that you use Ignition config files within 12 hours after they are generated because the 24-hour certificate rotates from 16 to 22 hours after the cluster is installed. By using the Ignition config files within 12 hours, you can avoid installation failure if the certificate update runs during installation.

Prerequisites

You obtained the OpenShift Container Platform installation program. For a restricted network installation, these files are on your mirror host.
You created the install-config.yaml installation configuration file.

Procedure

Change to the directory that contains the installation program and generate the Kubernetes manifests for the cluster:
```
$ ./openshift-install create manifests --dir <installation_directory> 1
```
1
For <installation_directory>, specify the installation directory that contains the install-config.yaml file you created.

Warning

If you are installing a three-node cluster, skip the following step to allow the control plane nodes to be schedulable.

Important

When you configure control plane nodes from the default unschedulable to schedulable, additional subscriptions are required. This is because control plane nodes then become worker nodes.

Check that the mastersSchedulable parameter in the <installation_directory>/manifests/cluster-scheduler-02-config.yml Kubernetes manifest file is set to false. This setting prevents pods from being scheduled on the control plane machines:
1. Open the <installation_directory>/manifests/cluster-scheduler-02-config.yml file.
2. Locate the mastersSchedulable parameter and ensure that it is set to false.
3. Save and exit the file.
To create the Ignition configuration files, run the following command from the directory that contains the installation program:
```
$ ./openshift-install create ignition-configs --dir <installation_directory> 1
```
1
For <installation_directory>, specify the same installation directory.
The following files are generated in the directory:
```
.
├── auth
│   ├── kubeadmin-password
│   └── kubeconfig
├── bootstrap.ign
├── master.ign
├── metadata.json
└── worker.ign
```

1.3.10. Configuring chrony time service

You must set the time server and related settings used by the chrony time service (chronyd) by modifying the contents of the chrony.conf file and passing those contents to your nodes as a machine config.

Procedure

Create the contents of the chrony.conf file and encode it as base64. For example:

$ cat << EOF | base64
    pool 0.rhel.pool.ntp.org iburst 1
    driftfile /var/lib/chrony/drift
    makestep 1.0 3
    rtcsync
    logdir /var/log/chrony
EOF

1: Specify any valid, reachable time source, such as the one provided by your DHCP server.

Example output

ICAgIHNlcnZlciBjbG9jay5yZWRoYXQuY29tIGlidXJzdAogICAgZHJpZnRmaWxlIC92YXIvbGli
L2Nocm9ueS9kcmlmdAogICAgbWFrZXN0ZXAgMS4wIDMKICAgIHJ0Y3N5bmMKICAgIGxvZ2RpciAv
dmFyL2xvZy9jaHJvbnkK

Create the MachineConfig object file, replacing the base64 string with the one you just created. This example adds the file to master nodes. You can change it to worker or make an additional MachineConfig for the worker role. Create MachineConfig files for each type of machine that your cluster uses:

$ cat << EOF > ./99-masters-chrony-configuration.yaml
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
metadata:
  labels:
    machineconfiguration.openshift.io/role: master
  name: 99-masters-chrony-configuration
spec:
  config:
    ignition:
      config: {}
      security:
        tls: {}
      timeouts: {}
      version: 3.1.0
    networkd: {}
    passwd: {}
    storage:
      files:
      - contents:
          source: data:text/plain;charset=utf-8;base64,ICAgIHNlcnZlciBjbG9jay5yZWRoYXQuY29tIGlidXJzdAogICAgZHJpZnRmaWxlIC92YXIvbGliL2Nocm9ueS9kcmlmdAogICAgbWFrZXN0ZXAgMS4wIDMKICAgIHJ0Y3N5bmMKICAgIGxvZ2RpciAvdmFyL2xvZy9jaHJvbnkK
        mode: 420 1
        overwrite: true
        path: /etc/chrony.conf
  osImageURL: ""
EOF

1: Specify an octal value mode for the mode field in the machine config file. After creating the file and applying the changes, the mode is converted to a decimal value. You can check the YAML file with the command oc get mc <mc-name> -o yaml.

Make a backup copy of the configuration files.
Apply the configurations in one of two ways:
- If the cluster is not up yet, after you generate manifest files, add this file to the <installation_directory>/openshift directory, and then continue to create the cluster.
- If the cluster is already running, apply the file:
```
$ oc apply -f ./99-masters-chrony-configuration.yaml
```

1.3.11. Installing RHCOS and starting the OpenShift Container Platform bootstrap process

To install RHCOS on the machines, follow either the steps to use an ISO image or network PXE booting.

Note

You can configure RHCOS during ISO and PXE installations by using the following methods:

Kernel arguments: You can use kernel arguments to provide installation-specific information. For example, you can specify the locations of the RHCOS installation files that you uploaded to your HTTP server and the location of the Ignition config file for the type of node you are installing. For a PXE installation, you can use the APPEND parameter to pass the arguments to the kernel of the live installer. For an ISO installation, you can interrupt the live installation boot process to add the kernel arguments. In both installation cases, you can use special coreos.inst.* arguments to direct the live installer, as well as standard installation boot arguments for turning standard kernel services on or off.
Ignition configs: OpenShift Container Platform Ignition config files (*.ign) are specific to the type of node you are installing. You pass the location of a bootstrap, control plane, or compute node Ignition config file during the RHCOS installation so that it takes effect on first boot. In special cases, you can create a separate, limited Ignition config to pass to the live system. That Ignition config could do a certain set of tasks, such as reporting success to a provisioning system after completing installation. This special Ignition config is consumed by the coreos-installer to be applied on first boot of the installed system. Do not provide the standard control plane and compute node Ignition configs to the live ISO directly.
coreos-installer: You can boot the live ISO installer to a shell prompt, which allows you to prepare the permanent system in a variety of ways before first boot. In particular, you can run the coreos-installer command to identify various artifacts to include, work with disk partitions, and set up networking. In some cases, you can configure features on the live system and copy them to the installed system.

Note

As of OpenShift Container Platform 4.6, the RHCOS ISO and other installation artifacts provide support for installation on disks with 4K sectors.

1.3.11.1. Creating Red Hat Enterprise Linux CoreOS (RHCOS) machines using an ISO image

Before you install a cluster on 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 can be accessed from your computer, and from the machines that you create.

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.
Important
If 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.
Important
The RHCOS images might not change with every release of OpenShift Container Platform. You must download images with the highest version that is less than or equal to the OpenShift Container Platform version that you install. Use the image versions that match your OpenShift Container Platform version if they are available. Use only ISO images for this procedure. RHCOS qcow2 images are not supported for this installation type.
ISO file names resemble the following example:
rhcos-<version>-live.<architecture>.iso
Use the ISO to start the RHCOS installation. Use one of the following installation options:
- Burn the ISO image to a disk and boot it directly.
- Use ISO redirection via a LOM interface.
Boot the ISO image. You can interrupt the installation boot process to add kernel arguments. However, for this ISO procedure you should use the coreos-installer command instead of adding kernel arguments. If you run the live installer without options or interruption, the installer boots up to a shell prompt on the live system, ready for you to install RHCOS to disk.
Review the Advanced RHCOS installation reference section for different ways of configuring features, such as networking and disk partitions, before running the coreos-installer.
Run the coreos-installer command. At a minimum, you must identify the Ignition config file location for your node type, and the location of the disk you are installing to. Here is an example:
```
$ sudo coreos-installer install \
     --ignition-url=https://host/worker.ign /dev/sda
```
After RHCOS installs, the system reboots. During the system reboot, it applies the Ignition config file that you specified.
Continue to create the other machines for your cluster.
Important
You 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.

1.3.11.2. Creating Red Hat Enterprise Linux CoreOS (RHCOS) machines by PXE or iPXE booting

Before you install a cluster that uses manually-provisioned RHCOS nodes, such as bare metal, you must create RHCOS machines for it to use. You can use PXE or iPXE booting to create the machines.

Prerequisites

Obtain the Ignition config files for your cluster.
Configure suitable PXE or iPXE infrastructure.
Have access to an HTTP 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.
Important
You can add or change configuration settings in your Ignition configs before saving them to your HTTP server. If you plan to add more compute machines to your cluster after you finish installation, do not delete these files.
Obtain the RHCOS kernel, initramfs and rootfs files from the RHCOS image mirror page.
Important
The RHCOS artifacts might not change with every release of OpenShift Container Platform. You must download artifacts with the highest version that is less than or equal to the OpenShift Container Platform version that you install. Only use the appropriate kernel, initramfs, and rootfs artifacts described below for this procedure. RHCOS qcow2 images are not supported for this installation type.
The file names contain the OpenShift Container Platform version number. They resemble the following examples:
- kernel: rhcos-<version>-live-kernel-<architecture>
- initramfs: rhcos-<version>-live-initramfs.<architecture>.img
- rootfs: rhcos-<version>-live-rootfs.<architecture>.img
Upload the additional files that are required for your booting method:
- For traditional PXE, upload the kernel and initramfs files to your TFTP server and the rootfs file to your HTTP server.
- For iPXE, upload the kernel, initramfs, and rootfs files to your HTTP server.
  Important
  If you plan to add more compute machines to your cluster after you finish installation, do not delete these files.
Configure the network boot infrastructure so that the machines boot from their local disks after RHCOS is installed on them.
Configure PXE or iPXE installation for the RHCOS images.
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 http://<HTTP_server>/rhcos-<version>-live-kernel-<architecture> 1
    APPEND initrd=http://<HTTP_server>/rhcos-<version>-live-initramfs.<architecture>.img coreos.live.rootfs_url=http://<HTTP_server>/rhcos-<version>-live-rootfs.<architecture>.img coreos.inst.install_dev=/dev/sda coreos.inst.ignition_url=http://<HTTP_server>/bootstrap.ign 2 3
```
  1
  Specify the location of the live kernel file that you uploaded to your HTTP server. The URL must be HTTP, TFTP, or FTP; HTTPS and NFS are not supported.
  2
  If you use multiple NICs, specify a single interface in the ip option. For example, to use DHCP on a NIC that is named eno1, set ip=eno1:dhcp.
  3
  Specify locations of the RHCOS files that you uploaded to your HTTP server. The initrd parameter value is the location of the initramfs file, the coreos.live.rootfs_url parameter value is the location of the rootfs file, and the coreos.inst.ignition_url parameter value is the location of the bootstrap Ignition config file. You can also add more kernel arguments to the APPEND line to configure networking or other boot options.
  Note
  This 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 the APPEND line. For example, add console=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?.
- For iPXE:
```
kernel http://<HTTP_server>/rhcos-<version>-live-kernel-<architecture> initrd=main coreos.live.rootfs_url=http://<HTTP_server>/rhcos-<version>-live-rootfs.<architecture>.img coreos.inst.install_dev=/dev/sda coreos.inst.ignition_url=http://<HTTP_server>/bootstrap.ign 1 2
initrd --name main http://<HTTP_server>/rhcos-<version>-live-initramfs.<architecture>.img 3
boot
```
  1
  Specify locations of the RHCOS files that you uploaded to your HTTP server. The kernel parameter value is the location of the kernel file, the initrd=main argument is needed for booting on UEFI systems, the coreos.live.rootfs_url parameter value is the location of the rootfs file, and the coreos.inst.ignition_url parameter value is the location of the bootstrap Ignition config file.
  2
  If you use multiple NICs, specify a single interface in the ip option. For example, to use DHCP on a NIC that is named eno1, set ip=eno1:dhcp.
  3
  Specify the location of the initramfs file that you uploaded to your HTTP server.
  Note
  This 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 the kernel line. For example, add console=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 PXE UEFI, perform the following actions:
1. Provide the shimx64.efi and grubx64.efi EFI binaries and the grub.cfg file that are required for booting the system.
  - Extract the necessary EFI binaries by mounting the RHCOS ISO to your host and then mounting the images/efiboot.img file to your host:
    $ mkdir -p /mnt/iso
    $ mkdir -p /mnt/efiboot
    $ mount -o loop rhcos-installer.x86_64.iso /mnt/iso
    $ mount -o loop,ro /mnt/iso/images/efiboot.img /mnt/efiboot
  - From the efiboot.img mount point, copy the EFI/redhat/shimx64.efi and EFI/redhat/grubx64.efi files to your TFTP server:
    $ cp /mnt/efiboot/EFI/redhat/shimx64.efi .
    $ cp /mnt/efiboot/EFI/redhat/grubx64.efi .
    $ umount /mnt/efiboot
    $ umount /mnt/iso
  - Copy the EFI/redhat/grub.cfg file that is included in the RHCOS ISO to your TFTP server.
2. Edit the grub.cfg file to include arguments similar to the following:
```
menuentry 'Install Red Hat Enterprise Linux CoreOS' --class fedora --class gnu-linux --class gnu --class os {
	linuxefi rhcos-<version>-live-kernel-<architecture> coreos.inst.install_dev=/dev/sda coreos.live.rootfs_url=http://<HTTP_server>/rhcos-<version>-live-rootfs.<architecture>.img coreos.inst.ignition_url=http://<HTTP_server>/bootstrap.ign
	initrdefi rhcos-<version>-live-initramfs.<architecture>.img
}
```
  where:
  rhcos-<version>-live-kernel-<architecture>
  Specifies the kernel file that you uploaded to your TFTP server.
  http://<HTTP_server>/rhcos-<version>-live-rootfs.<architecture>.img
  Specifies the location of the live rootfs image that you uploaded to your HTTP server.
  http://<HTTP_server>/bootstrap.ign
  Specifies the location of the bootstrap Ignition config file that you uploaded to your HTTP server.
  rhcos-<version>-live-initramfs.<architecture>.img
  Specifies the location of the initramfs file that you uploaded to your TFTP server.
  Note
  For more information on how to configure a PXE server for UEFI boot, see the Red Hat Knowledgebase article: How to configure/setup a PXE server for UEFI boot for Red Hat Enterprise Linux?.
Continue to create the machines for your cluster.
Important
You 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.

1.3.11.3. Advanced Red Hat Enterprise Linux CoreOS (RHCOS) installation configuration

Passing kernel arguments to the live installer
Running coreos-installer manually from the live system
Embedding Ignition configs in an ISO

1.3.11.3.1. Using advanced networking options for PXE and ISO installations

Pass special kernel parameters when you boot the live installer.
Use a machine config to copy networking files to the installed system.
Configure networking from a live installer shell prompt, then copy those settings to the installed system so that they take effect when the installed system first boots.

To configure a PXE or iPXE installation, use one of the following options:

See the "Advanced RHCOS installation reference" tables.
Use a machine config to copy networking files to the installed system.

To configure an ISO installation, use the following procedure.

Procedure

Boot the ISO installer.
From the live system shell prompt, configure networking for the live system using available RHEL tools, such as nmcli or nmtui.
Run the coreos-installer command to install the system, adding the --copy-network option to copy networking configuration. For example:
```
$ coreos-installer install --copy-network \
     --ignition-url=http://host/worker.ign /dev/sda
```
Important
The --copy-network option only copies networking configuration found under /etc/NetworkManager/system-connections. In particular, it does not copy the system hostname.
Reboot into the installed system.

1.3.11.3.2. Disk partitioning

However, there are two cases where you might want to intervene to override the default partitioning when installing an OpenShift Container Platform node:

Create separate partitions: For greenfield installations on an empty disk, you might want to add separate storage to a partition. This is officially supported for making /var or a subdirectory of /var, such as /var/lib/etcd, a separate partition, but not both.
Important
Kubernetes supports only two filesystem partitions. If you add more than one partition to the original configuration, Kubernetes cannot monitor all of them.
Retain existing partitions: For a brownfield installation where you are reinstalling OpenShift Container Platform on an existing node and want to retain data partitions installed from your previous operating system, there are both boot arguments and options to coreos-installer that allow you to retain existing data partitions.

1.3.11.3.2.1. Creating a separate `/var` partition

OpenShift Container Platform supports the addition of a single partition to attach storage to either the /var partition or a subdirectory of /var. For example:

/var/lib/containers: Holds container-related content that can grow as more images and containers are added to a system.
/var/lib/etcd: Holds data that you might want to keep separate for purposes such as performance optimization of etcd storage.
/var: Holds data that you might want to keep separate for purposes such as auditing.

Procedure

Create a directory to hold the OpenShift Container Platform installation files:
```
$ mkdir $HOME/clusterconfig
```

Run openshift-install to create a set of files in the manifest and openshift subdirectories. Answer the system questions as you are prompted:

$ openshift-install create manifests --dir $HOME/clusterconfig
? SSH Public Key ...
$ ls $HOME/clusterconfig/openshift/
99_kubeadmin-password-secret.yaml
99_openshift-cluster-api_master-machines-0.yaml
99_openshift-cluster-api_master-machines-1.yaml
99_openshift-cluster-api_master-machines-2.yaml
...

Create a MachineConfig object and add it to a file in the openshift directory. For example, name the file 98-var-partition.yaml, change the disk device name to the name of the storage device on the worker systems, and set the storage size as appropriate. This example places the /var directory on a separate partition:
```
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
metadata:
  labels:
    machineconfiguration.openshift.io/role: worker
  name: 98-var-partition
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      disks:
      - device: /dev/<device_name> 1
        partitions:
        - label: var
          startMiB: <partition_start_offset> 2
          sizeMiB: <partition_size> 3
      filesystems:
        - device: /dev/disk/by-partlabel/var
          path: /var
          format: xfs
    systemd:
      units:
        - name: var.mount 4
          enabled: true
          contents: |
            [Unit]
            Before=local-fs.target
            [Mount]
            What=/dev/disk/by-partlabel/var
            Where=/var
            Options=defaults,prjquota 5
            [Install]
            WantedBy=local-fs.target
```
1
The storage device name of the disk that you want to partition.
2
When adding a data partition to the boot disk, a minimum value of 25000 mebibytes is recommended. The root file system is automatically resized to fill all available space up to the specified offset. If no value is specified, or if the specified value is smaller than the recommended minimum, the resulting root file system will be too small, and future reinstalls of RHCOS might overwrite the beginning of the data partition.
3
The size of the data partition in mebibytes.
4
The name of the mount unit must match the directory specified in the Where= directive. For example, for a filesystem mounted on /var/lib/containers, the unit must be named var-lib-containers.mount.
5
The prjquota mount option must be enabled for filesystems used for container storage.
Note
When creating a separate /var partition, you cannot use different instance types for worker nodes, if the different instance types do not have the same device name.

Run openshift-install again to create Ignition configs from a set of files in the manifest and openshift subdirectories:

$ openshift-install create ignition-configs --dir $HOME/clusterconfig
$ ls $HOME/clusterconfig/
auth  bootstrap.ign  master.ign  metadata.json  worker.ign

Now you can use the Ignition config files as input to the ISO or PXE manual installation procedures to install Red Hat Enterprise Linux CoreOS (RHCOS) systems.

1.3.11.3.2.2. Retaining existing partitions

Saved partitions might be partitions from an existing OpenShift Container Platform system that has data partitions that you want to keep. Here are a few tips:

If you save existing partitions, and those partitions do not leave enough space for RHCOS, installation will fail without damaging the saved partitions.
Identify the disk partitions you want to keep either by partition label or by number.

For an ISO installation

This example preserves any partition in which the partition label begins with data (data*):

# coreos-installer install --ignition-url http://10.0.2.2:8080/user.ign \
        --save-partlabel 'data*' /dev/sda

The following example illustrates running the coreos-installer in a way that preserves the sixth (6) partition on the disk:

# coreos-installer install --ignition-url http://10.0.2.2:8080/user.ign \
        --save-partindex 6 /dev/sda

This example preserves partitions 5 and higher:

# coreos-installer install --ignition-url http://10.0.2.2:8080/user.ign
        --save-partindex 5- /dev/sda

In the previous examples where partition saving is used, coreos-installer recreates the partition immediately.

For a PXE installation

This APPEND option preserves any partition in which the partition label begins with 'data' ('data*'):

coreos.inst.save_partlabel=data*

This APPEND option preserves partitions 5 and higher:

coreos.inst.save_partindex=5-

This APPEND option preserves partition 6:

coreos.inst.save_partindex=6

1.3.11.3.3. Identifying Ignition configs

When doing an RHCOS manual installation, there are two types of Ignition configs that you can provide, with different reasons for providing each one:

Permanent install Ignition config: Every manual RHCOS installation needs to pass one of the Ignition config files generated by openshift-installer, such as bootstrap.ign, master.ign and worker.ign, to carry out the installation.
Important
It is not recommended to modify these files.
For PXE installations, you pass the Ignition configs on the APPEND line using the coreos.inst.ignition_url= option. For ISO installations, after the ISO boots to the shell prompt, you identify the Ignition config on the coreos-installer command line with the --ignition-url= option. In both cases, only HTTP and HTTPS protocols are supported.
Live install Ignition config: This type must be created manually and should be avoided if possible, as it is not supported by Red Hat. With this method, the Ignition config passes to the live install medium, runs immediately upon booting, and performs setup tasks before and/or after the RHCOS system installs to disk. This method should only be used for performing tasks that must be performed once and not applied again later, such as with advanced partitioning that cannot be done using a machine config.
For PXE or ISO boots, you can create the Ignition config and APPEND the ignition.config.url= option to identify the location of the Ignition config. You also need to append ignition.firstboot ignition.platform.id=metal or the ignition.config.url option will be ignored.

1.3.11.3.3.1. Embedding an Ignition config in the RHCOS ISO

You can embed a live install Ignition config directly in an RHCOS ISO image. When the ISO image is booted, the embedded config will be applied automatically.

Procedure

Download the coreos-installer binary from the following image mirror page: https://mirror.openshift.com/pub/openshift-v4/clients/coreos-installer/latest/.
Retrieve the RHCOS ISO image and the Ignition config file, and copy them into an accessible directory, such as /mnt:
```
# cp rhcos-<version>-live.x86_64.iso bootstrap.ign /mnt/
# chmod 644 /mnt/rhcos-<version>-live.x86_64.iso
```
Run the following command to embed the Ignition config into the ISO:
```
# ./coreos-installer iso ignition embed -i /mnt/bootstrap.ign \
     /mnt/rhcos-<version>-live.x86_64.iso
```
You can now use that ISO to install RHCOS using the specified live install Ignition config.
Important
Using coreos-installer iso ignition embed to embed a file generated by openshift-installer, such as bootstrap.ign, master.ign and worker.ign, is unsupported and not recommended.

To show the contents of the embedded Ignition config and direct it into a file, run:

# ./coreos-installer iso ignition show /mnt/rhcos-<version>-live.x86_64.iso > mybootstrap.ign

# diff -s bootstrap.ign mybootstrap.ign

Example output

Files bootstrap.ign and mybootstrap.ign are identical

To remove the Ignition config and return the ISO to its pristine state so you can reuse it, run:
```
# ./coreos-installer iso ignition remove /mnt/rhcos-<version>-live.x86_64.iso
```
You can now embed another Ignition config into the ISO or use the ISO in its pristine state.

1.3.11.3.4. Advanced RHCOS installation reference

Routing and bonding options at RHCOS boot prompt

Important

When adding networking arguments, you must also add the rd.neednet=1 kernel argument.

The following table describes how to use ip=, nameserver=, and bond= kernel arguments for live ISO installs.

Note

Ordering is important when adding kernel arguments: ip=, nameserver=, and then bond=.

Routing and bonding options for ISO

Description	Examples
To configure an IP address, either use DHCP (`ip=dhcp`) or set an individual static IP address (`ip=<host_ip>`). Then identify the DNS server IP address (`nameserver=<dns_ip>`) on each node. This example sets: The node’s IP address to `10.10.10.2` The gateway address to `10.10.10.254` The netmask to `255.255.255.0` The hostname to `core0.example.com` The DNS server address to `4.4.4.41`	ip=10.10.10.2::10.10.10.254:255.255.255.0:core0.example.com:enp1s0:none nameserver=4.4.4.41
Specify multiple network interfaces by specifying multiple `ip=` entries.	ip=10.10.10.2::10.10.10.254:255.255.255.0:core0.example.com:enp1s0:none ip=10.10.10.3::10.10.10.254:255.255.255.0:core0.example.com:enp2s0:none
Optional: You can configure routes to additional networks by setting an `rd.route=` value. If the additional network gateway is different from the primary network gateway, the default gateway must be the primary network gateway.	To configure the default gateway: ip=::10.10.10.254:::: To configure the route for the additional network: rd.route=20.20.20.0/24:20.20.20.254:enp2s0
Disable DHCP on a single interface, such as when there are two or more network interfaces and only one interface is being used.	ip=10.10.10.2::10.10.10.254:255.255.255.0:core0.example.com:enp1s0:none ip=::::core0.example.com:enp2s0:none
You can combine DHCP and static IP configurations on systems with multiple network interfaces.	ip=enp1s0:dhcp ip=10.10.10.2::10.10.10.254:255.255.255.0:core0.example.com:enp2s0:none
Optional: You can configure VLANs on individual interfaces by using the `vlan=` parameter.	To configure a VLAN on a network interface and use a static IP address: ip=10.10.10.2::10.10.10.254:255.255.255.0:core0.example.com:enp2s0.100:none vlan=enp2s0.100:enp2s0 To configure a VLAN on a network interface and to use DHCP: ip=enp2s0.100:dhcp vlan=enp2s0.100:enp2s0
You can provide multiple DNS servers by adding a `nameserver=` entry for each server.	nameserver=1.1.1.1 nameserver=8.8.8.8
Optional: Bonding multiple network interfaces to a single interface is supported using the `bond=` option. In these two examples: The syntax for configuring a bonded interface is: `bond=name[:network_interfaces][:options]` name is the bonding device name (`bond0`), network_interfaces represents a comma-separated list of physical (ethernet) interfaces (`em1,em2`), and options is a comma-separated list of bonding options. Enter `modinfo bonding` to see available options. When you create a bonded interface using `bond=`, you must specify how the IP address is assigned and other information for the bonded interface.	To configure the bonded interface to use DHCP, set the bond’s IP address to `dhcp`. For example: bond=bond0:em1,em2:mode=active-backup ip=bond0:dhcp To configure the bonded interface to use a static IP address, enter the specific IP address you want and related information. For example: bond=bond0:em1,em2:mode=active-backup ip=10.10.10.2::10.10.10.254:255.255.255.0:core0.example.com:bond0:none
Optional: You can configure VLANs on bonded interfaces by using the `vlan=` parameter.	To configure the bonded interface with a VLAN and to use DHCP: ip=bond0.100:dhcp bond=bond0:em1,em2:mode=active-backup vlan=bond0.100:bond0 To configure the bonded interface with a VLAN and to use a static IP address: ip=10.10.10.2::10.10.10.254:255.255.255.0:core0.example.com:bond0.100:none bond=bond0:em1,em2:mode=active-backup vlan=bond0.100:bond0
Optional: Network teaming can be used as an alternative to bonding by using the `team=` parameter. In this example: The syntax for configuring a team interface is: `team=name[:network_interfaces]` name is the team device name (`team0`) and network_interfaces represents a comma-separated list of physical (ethernet) interfaces (`em1, em2`). Note Teaming is planned to be deprecated when RHCOS switches to an upcoming version of RHEL. For more information, see this Red Hat Knowledgebase Article.	To configure a network team: team=team0:em1,em2 ip=team0:dhcp

`coreos.inst` boot options for ISO or PXE install

While you can pass most standard installation boot arguments to the live installer, there are several arguments that are specific to the RHCOS live installer.

For ISO, these options can be added by interrupting the RHCOS installer.
For PXE or iPXE, these options must be added to the APPEND line before starting the PXE kernel. You cannot interrupt a live PXE install.

The following table shows the RHCOS live installer boot options for ISO and PXE installs.

Table 1.37. coreos.inst boot options
Argument	Description
`coreos.inst.install_dev`	Required. The block device on the system to install to. It is recommended to use the full path, such as `/dev/sda`, although `sda` is allowed.
`coreos.inst.ignition_url`	Optional: The URL of the Ignition config to embed into the installed system. If no URL is specified, no Ignition config is embedded.
`coreos.inst.save_partlabel`	Optional: Comma-separated labels of partitions to preserve during the install. Glob-style wildcards are permitted. The specified partitions do not need to exist.
`coreos.inst.save_partindex`	Optional: Comma-separated indexes of partitions to preserve during the install. Ranges `m`-`n` are permitted, and either `m` or `n` can be omitted. The specified partitions do not need to exist.
`coreos.inst.insecure`	Optional: Permits the OS image that is specified by `coreos.inst.image_url` to be unsigned.
`coreos.inst.image_url`	Optional: Download and install the specified RHCOS image. This argument should not be used in production environments and is intended for debugging purposes only. While this argument can be used to install a version of RHCOS that does not match the live media, it is recommended that you instead use the media that matches the version you want to install. If you are using `coreos.inst.image_url`, you must also use `coreos.inst.insecure`. This is because the bare-metal media are not GPG-signed for OpenShift Container Platform. Only HTTP and HTTPS protocols are supported.
`coreos.inst.skip_reboot`	Optional: The system will not reboot after installing. Once the install finishes, you will receive a prompt that allows you to inspect what is happening during installation. This argument should not be used in production environments and is intended for debugging purposes only.
`coreos.inst.platform_id`	Optional: The Ignition platform ID of the platform the RHCOS image is being installed on. Default is `metal`. This option determines whether or not to request an Ignition config from the cloud provider, such as VMware. For example: `coreos.inst.platform_id=vmware`.
`ignition.config.url`	Optional: The URL of the Ignition config for the live boot. For example, this can be used to customize how `coreos-installer` is invoked, or to run code before or after the installation. This is different from `coreos.inst.ignition_url`, which is the Ignition config for the installed system.

`coreos-installer` options for ISO install

The following table shows the options and subcommands you can pass to the coreos-installer command from a shell prompt during a live install.

Table 1.38. coreos-installer command-line options, arguments, and subcommands
Command-line options
Option	Description
`-u`, `--image-url <url>`	Specify the image URL manually.
`-f`, `--image-file <path>`	Specify a local image file manually.
`-i,` `--ignition-file <path>`	Embed an Ignition config from a file.
`-I`, `--ignition-url <URL>`	Embed an Ignition config from a URL.
`--ignition-hash <digest>`	Digest `type-value` of the Ignition config.
`-p`, `--platform <name>`	Override the Ignition platform ID.
`--append-karg <arg>…`	Append the default kernel argument.
`--delete-karg <arg>…`	Delete the default kernel argument.
`-n`, `--copy-network`	Copy the network configuration from the install environment. Important The `--copy-network` option only copies networking configuration found under `/etc/NetworkManager/system-connections`. In particular, it does not copy the system hostname.
`--network-dir <path>`	For use with `-n`. Default is `/etc/NetworkManager/system-connections/`.
`--save-partlabel <lx>..`	Save partitions with this label glob.
`--save-partindex <id>…`	Save partitions with this number or range.
`--offline`	Force offline installation.
`--insecure`	Skip signature verification.
`--insecure-ignition`	Allow Ignition URL without HTTPS or hash.
`--architecture <name>`	Target CPU architecture. Default is `x86_64`.
`--preserve-on-error`	Do not clear partition table on error.
`-h`, `--help`	Print help information.
Command-line argument
Argument	Description
`<device>`	The destination device.
coreos-installer embedded Ignition commands
Command	Description
`$ coreos-installer iso ignition embed <options> --ignition-file <file_path> <ISO_image>`	Embed an Ignition config in an ISO image.
`coreos-installer iso ignition show <options> <ISO_image>`	Show the embedded Ignition config from an ISO image.
`coreos-installer iso ignition remove <options> <ISO_image>`	Remove the embedded Ignition config from an ISO image.
coreos-installer ISO Ignition options
Option	Description
`-f`, `--force`	Overwrite an existing Ignition config.
`-i`, `--ignition-file <path>`	The Ignition config to be used. Default is `stdin`.
`-o`, `--output <path>`	Write the ISO to a new output file.
`-h`, `--help`	Print help information.
coreos-installer PXE Ignition commands
Command	Description
Note that not all of these options are accepted by all subcommands.
`coreos-installer pxe ignition wrap <options>`	Wrap an Ignition config in an image.
`coreos-installer pxe ignition unwrap <options> <image_name>`	Show the wrapped Ignition config in an image.
`coreos-installer pxe ignition unwrap <options> <initrd_name>`	Show the wrapped Ignition config in an `initrd` image.
coreos-installer PXE Ignition options
Option	Description
`-i`, `--ignition-file <path>`	The Ignition config to be used. Default is `stdin`.
`-o,` `--output <path>`	Write the ISO to a new output file.
`-h`, `--help`	Print help information.

1.3.12. Creating the cluster

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
```
1
For <installation_directory>, specify the path to the directory that you stored the installation files in.
2
To view different installation details, specify warn, debug, or error instead of info.
Example output
```
INFO Waiting up to 30m0s for the Kubernetes API at https://api.test.example.com:6443...
INFO API v1.19.0 up
INFO Waiting up to 30m0s for bootstrapping to complete...
INFO It is now safe to remove the bootstrap resources
```
The command succeeds when the Kubernetes API server signals that it has been bootstrapped on the control plane machines.
After bootstrap process is complete, remove the bootstrap machine from the load balancer.
Important
You must remove the bootstrap machine from the load balancer at this point. You can also remove or reformat the machine itself.

1.3.13. Logging in to the cluster by using the CLI

Prerequisites

You deployed an OpenShift Container Platform cluster.
You installed the oc CLI.

Procedure

Export the kubeadmin credentials:
```
$ export KUBECONFIG=<installation_directory>/auth/kubeconfig 1
```
1
For <installation_directory>, specify the path to the directory that you stored the installation files in.
Verify you can run oc commands successfully using the exported configuration:
```
$ oc whoami
```
Example output
```
system:admin
```

1.3.14. Approving the certificate signing requests for your machines

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  v1.19.0
master-1  Ready     master  63m  v1.19.0
master-2  Ready     master  64m  v1.19.0
```
The output lists all of the machines that you created.
Note
The preceding output might not include the compute nodes, also known as worker nodes, until some CSRs are approved.

Review the pending CSRs and ensure that you see the client requests with the Pending or Approved 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:
Note
Because 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.
Note
For clusters running on platforms that are not machine API enabled, such as bare metal and other user-provisioned infrastructure, you must implement a method of automatically approving the kubelet serving certificate requests (CSRs). If a request is not approved, then the oc exec, oc rsh, and oc logs commands cannot succeed, because a serving certificate is required when the API server connects to the kubelet. Any operation that contacts the Kubelet endpoint requires this certificate approval to be in place. The method must watch for new CSRs, confirm that the CSR was submitted by the node-bootstrapper service account in the system:node or system:admin groups, and confirm the identity of the node.
- To approve them individually, run the following command for each valid CSR:
```
$ oc adm certificate approve <csr_name> 1
```
  1
  <csr_name> is the name of a CSR from the list of current CSRs.
- To approve all pending CSRs, run the following command:
```
$ oc get csr -o go-template='{{range .items}}{{if not .status}}{{.metadata.name}}{{"\n"}}{{end}}{{end}}' | xargs --no-run-if-empty oc adm certificate approve
```
  Note
  Some Operators might not become available until some CSRs are approved.

Now that your client requests are approved, you must review the server requests for each machine that you added to the cluster:

$ oc get csr

Example output

NAME        AGE     REQUESTOR                                                                   CONDITION
csr-bfd72   5m26s   system:node:ip-10-0-50-126.us-east-2.compute.internal                       Pending
csr-c57lv   5m26s   system:node:ip-10-0-95-157.us-east-2.compute.internal                       Pending
...

If the remaining CSRs are not approved, and are in the Pending status, approve the CSRs for your cluster machines:
- To approve them individually, run the following command for each valid CSR:
```
$ oc adm certificate approve <csr_name> 1
```
  1
  <csr_name> is the name of a CSR from the list of current CSRs.
- To approve all pending CSRs, run the following command:
```
$ oc get csr -o go-template='{{range .items}}{{if not .status}}{{.metadata.name}}{{"\n"}}{{end}}{{end}}' | xargs oc adm certificate approve
```

After all client and server CSRs have been approved, the machines have the Ready status. Verify this by running the following command:

$ oc get nodes

Example output

NAME      STATUS    ROLES   AGE  VERSION
master-0  Ready     master  73m  v1.20.0
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

Note

It 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.

1.3.15. Initial Operator configuration

After the control plane initializes, you must immediately configure some Operators so that they all become available.

Prerequisites

Your control plane has initialized.

Procedure

Watch the cluster components come online:

$ watch -n5 oc get clusteroperators

Example output

NAME                                       VERSION AVAILABLE   PROGRESSING   DEGRADED   SINCE
authentication                             4.6.0   True        False         False      3h56m
cloud-credential                           4.6.0   True        False         False      29h
cluster-autoscaler                         4.6.0   True        False         False      29h
config-operator                            4.6.0   True        False         False      6h39m
console                                    4.6.0   True        False         False      3h59m
csi-snapshot-controller                    4.6.0   True        False         False      4h12m
dns                                        4.6.0   True        False         False      4h15m
etcd                                       4.6.0   True        False         False      29h
image-registry                             4.6.0   True        False         False      3h59m
ingress                                    4.6.0   True        False         False      4h30m
insights                                   4.6.0   True        False         False      29h
kube-apiserver                             4.6.0   True        False         False      29h
kube-controller-manager                    4.6.0   True        False         False      29h
kube-scheduler                             4.6.0   True        False         False      29h
kube-storage-version-migrator              4.6.0   True        False         False      4h2m
machine-api                                4.6.0   True        False         False      29h
machine-approver                           4.6.0   True        False         False      6h34m
machine-config                             4.6.0   True        False         False      3h56m
marketplace                                4.6.0   True        False         False      4h2m
monitoring                                 4.6.0   True        False         False      6h31m
network                                    4.6.0   True        False         False      29h
node-tuning                                4.6.0   True        False         False      4h30m
openshift-apiserver                        4.6.0   True        False         False      3h56m
openshift-controller-manager               4.6.0   True        False         False      4h36m
openshift-samples                          4.6.0   True        False         False      4h30m
operator-lifecycle-manager                 4.6.0   True        False         False      29h
operator-lifecycle-manager-catalog         4.6.0   True        False         False      29h
operator-lifecycle-manager-packageserver   4.6.0   True        False         False      3h59m
service-ca                                 4.6.0   True        False         False      29h
storage                                    4.6.0   True        False         False      4h30m

Configure the Operators that are not available.

1.3.15.1. Disabling the default OperatorHub sources

Operator catalogs that source content provided by Red Hat and community projects are configured for OperatorHub by default during an OpenShift Container Platform installation. In a restricted network environment, you must disable the default catalogs as a cluster administrator.

Procedure

Disable the sources for the default catalogs by adding disableAllDefaultSources: true to the OperatorHub object:

$ oc patch OperatorHub cluster --type json \
    -p '[{"op": "add", "path": "/spec/disableAllDefaultSources", "value": true}]'

Tip

Alternatively, you can use the web console to manage catalog sources. From the Administration Cluster Settings Global Configuration OperatorHub page, click the Sources tab, where you can create, delete, disable, and enable individual sources.

1.3.15.2. Image registry storage configuration

Additional instructions are provided for allowing the image registry to use block storage types by using the Recreate rollout strategy during upgrades.

1.3.15.2.1. Changing the image registry’s management state

To start the image registry, you must change the Image Registry Operator configuration’s managementState from Removed to Managed.

Procedure

Change managementState Image Registry Operator configuration from Removed to Managed. For example:

$ oc patch configs.imageregistry.operator.openshift.io cluster --type merge --patch '{"spec":{"managementState":"Managed"}}'

1.3.15.2.2. Configuring registry storage for bare metal and other manual installations

As a cluster administrator, following installation you must configure your registry to use storage.

Prerequisites

Cluster administrator permissions.
A cluster that uses manually-provisioned Red Hat Enterprise Linux CoreOS (RHCOS) nodes, such as bare metal.
Persistent storage provisioned for your cluster, such as Red Hat OpenShift Container Storage.
Important
OpenShift 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 the configs.imageregistry/cluster resource.
Note
When 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
```
Note
If the storage type is emptyDIR, the replica number cannot be greater than 1.
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 an image-registry-storage PVC.
Check the clusteroperator status:
```
$ oc get clusteroperator image-registry
```
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
```

1.3.15.2.3. Configuring storage for the image registry in non-production clusters

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":{}}}}'
```
Warning
Configure 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.

1.3.15.2.4. Configuring block registry storage

To allow the image registry to use block storage types during upgrades as a cluster administrator, you can use the Recreate rollout strategy.

Important

Procedure

To set the image registry storage as a block storage type, patch the registry so that it uses the Recreate rollout strategy and runs with only one (1) replica:
```
$ oc patch config.imageregistry.operator.openshift.io/cluster --type=merge -p '{"spec":{"rolloutStrategy":"Recreate","replicas":1}}'
```
Provision the PV for the block storage device, and create a PVC for that volume. The requested block volume uses the ReadWriteOnce (RWO) access mode.
Edit the registry configuration so that it references the correct PVC.

1.3.16. Completing installation on user-provisioned infrastructure

After you complete the Operator configuration, you can finish installing the cluster on infrastructure that you provide.

Prerequisites

Your control plane has initialized.
You have completed the initial Operator configuration.

Procedure

Confirm that all the cluster components are online with the following command:

$ watch -n5 oc get clusteroperators

Example output

NAME                                       VERSION AVAILABLE   PROGRESSING   DEGRADED   SINCE
authentication                             4.6.0   True        False         False      3h56m
cloud-credential                           4.6.0   True        False         False      29h
cluster-autoscaler                         4.6.0   True        False         False      29h
config-operator                            4.6.0   True        False         False      6h39m
console                                    4.6.0   True        False         False      3h59m
csi-snapshot-controller                    4.6.0   True        False         False      4h12m
dns                                        4.6.0   True        False         False      4h15m
etcd                                       4.6.0   True        False         False      29h
image-registry                             4.6.0   True        False         False      3h59m
ingress                                    4.6.0   True        False         False      4h30m
insights                                   4.6.0   True        False         False      29h
kube-apiserver                             4.6.0   True        False         False      29h
kube-controller-manager                    4.6.0   True        False         False      29h
kube-scheduler                             4.6.0   True        False         False      29h
kube-storage-version-migrator              4.6.0   True        False         False      4h2m
machine-api                                4.6.0   True        False         False      29h
machine-approver                           4.6.0   True        False         False      6h34m
machine-config                             4.6.0   True        False         False      3h56m
marketplace                                4.6.0   True        False         False      4h2m
monitoring                                 4.6.0   True        False         False      6h31m
network                                    4.6.0   True        False         False      29h
node-tuning                                4.6.0   True        False         False      4h30m
openshift-apiserver                        4.6.0   True        False         False      3h56m
openshift-controller-manager               4.6.0   True        False         False      4h36m
openshift-samples                          4.6.0   True        False         False      4h30m
operator-lifecycle-manager                 4.6.0   True        False         False      29h
operator-lifecycle-manager-catalog         4.6.0   True        False         False      29h
operator-lifecycle-manager-packageserver   4.6.0   True        False         False      3h59m
service-ca                                 4.6.0   True        False         False      29h
storage                                    4.6.0   True        False         False      4h30m

Alternatively, the following command notifies you when all of the clusters are available. It also retrieves and displays credentials:

$ ./openshift-install --dir <installation_directory> wait-for install-complete 1

1: For <installation_directory>, specify the path to the directory that you stored the installation files in.

Example output

INFO Waiting up to 30m0s for the cluster to initialize...

The command succeeds when the Cluster Version Operator finishes deploying the OpenShift Container Platform cluster from Kubernetes API server.

Important

The Ignition config files that the installation program generates contain certificates that expire after 24 hours, which are then renewed at that time. If the cluster is shut down before renewing the certificates and the cluster is later restarted after the 24 hours have elapsed, the cluster automatically recovers the expired certificates. The exception is that you must manually approve the pending node-bootstrapper certificate signing requests (CSRs) to recover kubelet certificates. See the documentation for Recovering from expired control plane certificates for more information.
It is recommended that you use Ignition config files within 12 hours after they are generated because the 24-hour certificate rotates from 16 to 22 hours after the cluster is installed. By using the Ignition config files within 12 hours, you can avoid installation failure if the certificate update runs during installation.

Confirm that the Kubernetes API server is communicating with the pods.

To view a list of all pods, use the following command:

$ oc get pods --all-namespaces

Example output

NAMESPACE                         NAME                                            READY   STATUS      RESTARTS   AGE
openshift-apiserver-operator      openshift-apiserver-operator-85cb746d55-zqhs8   1/1     Running     1          9m
openshift-apiserver               apiserver-67b9g                                 1/1     Running     0          3m
openshift-apiserver               apiserver-ljcmx                                 1/1     Running     0          1m
openshift-apiserver               apiserver-z25h4                                 1/1     Running     0          2m
openshift-authentication-operator authentication-operator-69d5d8bf84-vh2n8        1/1     Running     0          5m
...

View the logs for a pod that is listed in the output of the previous command by using the following command:
```
$ oc logs <pod_name> -n <namespace> 1
```
1
Specify the pod name and namespace, as shown in the output of the previous command.
If the pod logs display, the Kubernetes API server can communicate with the cluster machines.

1.3.17. Telemetry access for OpenShift Container Platform

Additional resources

See About remote health monitoring for more information about the Telemetry service

1.3.18. Next steps

Customize your cluster.
Configure image streams for the Cluster Samples Operator and the must-gather tool.
Learn how to use Operator Lifecycle Manager (OLM) on restricted networks.
If the mirror registry that you used to install your cluster has a trusted CA, add it to the cluster by configuring additional trust stores.
If necessary, you can opt out of remote health reporting.

Chapter 1. Installing on bare metal

1.1. Installing a cluster on bare metal

1.1.1. Prerequisites

1.1.2. Internet access for OpenShift Container Platform

1.1.3. Machine requirements for a cluster with user-provisioned infrastructure

1.1.3.1. Required machines

1.1.3.2. Network connectivity requirements

1.1.3.3. Minimum resource requirements

1.1.3.4. Certificate signing requests management

1.1.4. Creating the user-provisioned infrastructure

1.1.4.1. Networking requirements for user-provisioned infrastructure

Network topology requirements

Load balancers

NTP configuration

1.1.4.2. User-provisioned DNS requirements

1.1.5. Generating an SSH private key and adding it to the agent

1.1.6. Obtaining the installation program

1.1.7. Installing the OpenShift CLI by downloading the binary

1.1.7.1. Installing the OpenShift CLI on Linux

1.1.7.2. Installing the OpenShift CLI on Windows

1.1.7.3. Installing the OpenShift CLI on macOS

1.1.8. Manually creating the installation configuration file

1.1.8.1. Installation configuration parameters

1.1.8.1.1. Required configuration parameters

1.1.8.1.2. Network configuration parameters

1.1.8.1.3. Optional configuration parameters

1.1.8.2. Sample install-config.yaml file for bare metal

1.1.8.3. Configuring the cluster-wide proxy during installation

1.1.9. Configuring a three-node cluster

1.1.10. Creating the Kubernetes manifest and Ignition config files

1.1.11. Installing RHCOS and starting the OpenShift Container Platform bootstrap process

1.1.11.1. Creating Red Hat Enterprise Linux CoreOS (RHCOS) machines using an ISO image

1.1.11.2. Creating Red Hat Enterprise Linux CoreOS (RHCOS) machines by PXE or iPXE booting

1.1.11.3. Advanced Red Hat Enterprise Linux CoreOS (RHCOS) installation configuration

1.1.11.3.1. Using advanced networking options for PXE and ISO installations

1.1.11.3.2. Disk partitioning

1.1.11.3.2.1. Creating a separate /var partition

1.1.11.3.2.2. Retaining existing partitions

1.1.11.3.3. Identifying Ignition configs

1.1.11.3.3.1. Embedding an Ignition config in the RHCOS ISO

1.1.11.3.4. Advanced RHCOS installation reference

Routing and bonding options at RHCOS boot prompt

coreos.inst boot options for ISO or PXE install

coreos-installer options for ISO install

1.1.12. Creating the cluster

1.1.13. Logging in to the cluster by using the CLI

1.1.14. Approving the certificate signing requests for your machines

1.1.15. Initial Operator configuration

1.1.15.1. Image registry removed during installation

1.1.15.2. Image registry storage configuration

1.1.15.2.1. Configuring registry storage for bare metal and other manual installations

1.1.15.2.2. Configuring storage for the image registry in non-production clusters

1.1.15.2.3. Configuring block registry storage

1.1.16. Completing installation on user-provisioned infrastructure

1.1.17. Telemetry access for OpenShift Container Platform

1.1.18. Next steps

1.2. Installing a cluster on bare metal with network customizations

1.2.1. Prerequisites

1.2.2. Internet access for OpenShift Container Platform

1.2.3. Machine requirements for a cluster with user-provisioned infrastructure

1.2.3.1. Required machines

1.2.3.2. Network connectivity requirements

1.2.3.3. Minimum resource requirements

1.2.3.4. Certificate signing requests management

1.2.4. Creating the user-provisioned infrastructure

1.2.4.1. Networking requirements for user-provisioned infrastructure

Network topology requirements

Load balancers

NTP configuration

1.2.4.2. User-provisioned DNS requirements

1.2.5. Generating an SSH private key and adding it to the agent

1.2.6. Obtaining the installation program

1.2.7. Installing the OpenShift CLI by downloading the binary

1.2.7.1. Installing the OpenShift CLI on Linux

1.2.7.2. Installing the OpenShift CLI on Windows

1.2.7.3. Installing the OpenShift CLI on macOS

1.2.8. Manually creating the installation configuration file

1.2.8.1. Installation configuration parameters

1.2.8.1.1. Required configuration parameters

1.2.8.1.2. Network configuration parameters

1.1.11.3.2.1. Creating a separate `/var` partition

`coreos.inst` boot options for ISO or PXE install

`coreos-installer` options for ISO install

1.2.13.3.2.1. Creating a separate `/var` partition

`coreos.inst` boot options for ISO or PXE install

`coreos-installer` options for ISO install

1.3.11.3.2.1. Creating a separate `/var` partition