In OpenShift Container Platform version 4.2, you can install a cluster with a customized network configuration on infrastructure that the installation program provisions on Google Cloud Platform (GCP). 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. To customize the installation, you modify parameters in the install-config.yaml file before you install the cluster.

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

Prerequisites

Internet and Telemetry access for OpenShift Container Platform

In OpenShift Container Platform 4.2, you require access to the internet to install and entitle your cluster. The Telemetry service, which runs by default to provide metrics about cluster health and the success of updates, also requires internet access. If your cluster is connected to the internet, Telemetry runs automatically, and your cluster is registered to the Red Hat OpenShift Cluster Manager. From there, you can allocate entitlements to your cluster.

You must have internet access to:

  • Access the Red Hat OpenShift Cluster Manager page to download the installation program and perform subscription management and entitlement. If the cluster has internet access and you do not disable Telemetry, that service automatically entitles your cluster. If the Telemetry service cannot entitle your cluster, you must manually entitle it on the Cluster registration page.

  • Access Quay.io to obtain the packages that are required to install your cluster.

  • Obtain the packages that are required to perform cluster updates.

If your cluster cannot have direct internet access, you can perform a restricted network installation on 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.

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 to the installation program.

You can use this key to SSH into the master nodes as the user core. When you deploy the cluster, the key is added to the core user’s ~/.ssh/authorized_keys list.

You must use a local key, not one that you configured with platform-specific approaches such as AWS key pairs.

Procedure
  1. 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 rsa -b 4096 -N '' \
        -f <path>/<file_name> (1)
    1 Specify the path and file name, such as ~/.ssh/id_rsa, of the SSH key.

    Running this command generates an SSH key that does not require a password in the location that you specified.

  2. Start the ssh-agent process as a background task:

    $ eval "$(ssh-agent -s)"
    
    Agent pid 31874
  3. Add your SSH private key to the ssh-agent:

    $ ssh-add <path>/<file_name> (1)
    
    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.

Obtaining the installation program

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

Prerequisites
  • You must install the cluster from a computer that uses Linux or macOS.

  • You need 500 MB of local disk space to download the installation program.

Procedure
  1. Access the Infrastructure Provider page on the Red Hat OpenShift Cluster Manager site. If you have a Red Hat account, log in with your credentials. If you do not, create an account.

  2. 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.

    The installation program creates several files on the computer that you use to install your cluster. You must keep both the installation program and the files that the installation program creates after you finish installing the cluster.

  3. Extract the installation program. For example, on a computer that uses a Linux operating system, run the following command:

    $ tar xvf <installation_program>.tar.gz
  4. From the Pull Secret page on the Red Hat OpenShift Cluster Manager site, download your installation pull secret as a .txt file. This pull secret allows you to authenticate with the services that are provided by the included authorities, including Quay.io, which serves the container images for OpenShift Container Platform components.

Creating the installation configuration file

You can customize your installation of OpenShift Container Platform on Google Cloud Platform (GCP).

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

Procedure
  1. Create the install-config.yaml file.

    1. Run the following command:

      $ ./openshift-install create install-config --dir=<installation_directory> (1)
      1 For <installation_directory>, specify the directory name to store the files that the installation program creates.

      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.

    2. At the prompts, provide the configuration details for your cloud:

      1. Optional: Select an SSH key to use to access your cluster machines.

        For production OpenShift Container Platform clusters on which you want to perform installation debugging or disaster recovery on, specify an SSH key that your ssh-agent process uses.

      2. Select gcp as the platform to target.

      3. If you have not configured the service account key for your GCP account on your computer, you must obtain it from GCP and paste the contents of the file or enter the absolute path to the file.

      4. Select the project ID to provision the cluster in. The default value is specified by the service account that you configured.

      5. Select the region to deploy the cluster to.

      6. Select the base domain to deploy the cluster to. The base domain corresponds to the public DNS zone that you created for your cluster.

      7. Enter a descriptive name for your cluster. If you provide a name that is longer than 6 characters, only the first 6 characters will be used in the infrastructure ID that is generated from the cluster name.

      8. Paste the pull secret that you obtained from the Pull Secret page on the Red Hat OpenShift Cluster Manager site.

  2. Modify the install-config.yaml file. You can find more information about the available parameters in the Installation configuration parameters section.

  3. Back up the install-config.yaml file so that you can use it to install multiple clusters.

    The install-config.yaml file is consumed during the installation process. If you want to reuse the file, you must back it up now.

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.

You cannot modify these parameters in the install-config.yaml file after installation.

Table 1. Required parameters
Parameter Description Values

baseDomain

The base domain of your cloud provider. This value 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.

controlPlane.platform

The cloud provider to host the control plane machines. This parameter value must match the compute.platform parameter value.

aws, azure, gcp, openstack, or {}

compute.platform

The cloud provider to host the worker machines. This parameter value must match the controlPlane.platform parameter value.

aws, azure, gcp, openstack, or {}

metadata.name

The name of your cluster.

A string that contains uppercase or lowercase letters, such as dev.

platform.<platform>.region

The region to deploy your cluster in.

A valid region for your cloud, such as us-east-1 for AWS, centralus for Azure, or region1 for Red Hat OpenStack Platform (RHOSP).

pullSecret

The pull secret that you obtained from the Pull Secret page on the Red Hat OpenShift Cluster Manager site. You use this pull secret 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.

{
   "auths":{
      "cloud.openshift.com":{
         "auth":"b3Blb=",
         "email":"you@example.com"
      },
      "quay.io":{
         "auth":"b3Blb=",
         "email":"you@example.com"
      }
   }
}
Table 2. Optional parameters
Parameter Description Values

sshKey

The SSH key to use to access your cluster machines.

For production OpenShift Container Platform clusters on which you want to perform installation debugging or disaster recovery on, specify an SSH key that your ssh-agent process uses.

A valid, local public SSH key that you added to the ssh-agent process.

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.

If you disable simultaneous multithreading, ensure that your capacity planning accounts for the dramatically decreased machine performance.

Enabled or Disabled

compute.replicas

The number of compute, or worker, machines to provision.

A positive integer greater than or equal to 2. The default value is 3.

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.

If you disable simultaneous multithreading, ensure that your capacity planning accounts for the dramatically decreased machine performance.

Enabled or Disabled

controlPlane.replicas

The number of control plane machines to provision.

A positive integer greater than or equal to 3. The default value is 3.

Network configuration parameters

You can modify your cluster network configuration parameters in the install-config.yaml configuration file. The following table describes the parameters.

You cannot modify these parameters in the install-config.yaml file after installation.

Table 3. Required network parameters
Parameter Description Value

networking.networkType

The network plug-in to deploy. The OpenShiftSDN plug-in is the only plug-in supported in OpenShift Container Platform 4.2.

The default value is OpenShiftSDN.

networking.clusterNetwork.cidr

A block of IP addresses from which Pod IP addresses are allocated. The OpenShiftSDN network plug-in supports multiple cluster networks. The address blocks for multiple cluster networks must not overlap. Select address pools large enough to fit your anticipated workload.

An IP address allocation in CIDR format. The default value is 10.128.0.0/14.

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, allowing for 510 (2^(32 - 23) - 2) Pod IP addresses.

A subnet prefix. The default value is 23.

networking.serviceNetwork

A block of IP addresses for services. OpenShiftSDN allows only one serviceNetwork block. The address block must not overlap with any other network block.

An IP address allocation in CIDR format. The default value is 172.30.0.0/16.

networking.machineCIDR

A block of IP addresses used by the OpenShift Container Platform installation program while installing the cluster. The address block must not overlap with any other network block.

An IP address allocation in CIDR format. The default value is 10.0.0.0/16.

Sample customized install-config.yaml file for GCP

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.

This sample YAML file is provided for reference only. You must obtain your install-config.yaml file by using the installation program and modify it.

apiVersion: v1
baseDomain: example.com (1)
controlPlane: (2)
  hyperthreading: Enabled  (3) (4)
  name: master
  platform:
    gcp:
      rootVolume:
        iops: 4000
        size: 500
        type: io1
      type: n1-standard-4
  replicas: 3
compute: (2)
- hyperthreading: Enabled (3)
  name: worker
  platform:
    gcp:
      rootVolume:
        iops: 2000
        size: 500
        type: io1 (5)
      type: n1-standard-4
  replicas: 3
metadata:
  name: test-cluster (1)
networking: (2)
  clusterNetwork:
  - cidr: 10.128.0.0/14
    hostPrefix: 23
  machineCIDR: 10.0.0.0/16
  networkType: OpenShiftSDN
  serviceNetwork:
  - 172.30.0.0/16
platform:
  gcp:
    ProjectID: openshift-production (1)
    region: us-central-1 (1)
pullSecret: '{"auths": ...}' (1)
sshKey: ssh-ed25519 AAAA... (6)
1 Required. The installation program prompts you for this value.
2 If you do not provide these parameters and values, the installation program provides the default value.
3 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. Although both sections currently define a single machine pool, it is possible that future versions of OpenShift Container Platform will support defining multiple compute pools during installation. Only one control plane pool is used.
4 Whether to enable or disable simultaneous multithreading, or hyperthreading. By default, simultaneous multithreading is enabled to increase the performance of your machines' cores. You can disable it by setting the parameter value to Disabled. If you disable simultaneous multithreading in some cluster machines, you must disable it in all cluster machines.

If you disable simultaneous multithreading, ensure that your capacity planning accounts for the dramatically decreased machine performance. Use larger machine types, such as n1-standard-8, for your machines if you disable simultaneous multithreading.

5 To configure faster storage for etcd, especially for larger clusters, set the storage type as io1 and set iops to 2000.
6 You can optionally provide the sshKey value that you use to access the machines in your cluster.

For production OpenShift Container Platform clusters on which you want to perform installation debugging or disaster recovery on, specify an SSH key that your ssh-agent process uses.

Modifying advanced network configuration parameters

You can modify the advanced network configuration parameters only before you install the cluster. Advanced configuration customization lets you integrate your cluster into your existing network environment by specifying an MTU or VXLAN port, by allowing customization of kube-proxy settings, and by specifying a different mode for the openshiftSDNConfig parameter.

Modifying the OpenShift Container Platform manifest files directly is not supported.

Prerequisites
  • Create the install-config.yaml file and complete any modifications to it.

Procedure
  1. Use the following command to create manifests:

    $ ./openshift-install create manifests --dir=<installation_directory> (1)
    1 For <installation_directory>, specify the name of the directory that contains the install-config.yaml file for your cluster.
  2. Create a file that is named cluster-network-03-config.yml in the <installation_directory>/manifests/ directory:

    $ touch <installation_directory>/manifests/cluster-network-03-config.yml (1)
    1 For <installation_directory>, specify the directory name that contains the manifests/ directory for your cluster.

    After creating the file, several network configuration files are in the manifests/ directory, as shown:

    $ ls <installation_directory>/manifests/cluster-network-*
    cluster-network-01-crd.yml
    cluster-network-02-config.yml
    cluster-network-03-config.yml
  3. Open the cluster-network-03-config.yml file in an editor and enter a CR that describes the Operator configuration you want:

    apiVersion: operator.openshift.io/v1
    kind: Network
    metadata:
      name: cluster
    spec: (1)
      clusterNetwork:
      - cidr: 10.128.0.0/14
        hostPrefix: 23
      serviceNetwork:
      - 172.30.0.0/16
      defaultNetwork:
        type: OpenShiftSDN
        openshiftSDNConfig:
          mode: NetworkPolicy
          mtu: 1450
          vxlanPort: 4789
    1 The parameters for the spec parameter are only an example. Specify your configuration for the Cluster Network Operator in the CR.

    The CNO provides default values for the parameters in the CR, so you must specify only the parameters that you want to change.

  4. Save the cluster-network-03-config.yml file and quit the text editor.

  5. Optional: Back up the manifests/cluster-network-03-config.yml file. The installation program deletes the manifests/ directory when creating the cluster.

Cluster Network Operator custom resource (CR)

The cluster network configuration in the Network.operator.openshift.io custom resource (CR) stores the configuration settings for the Cluster Network Operator (CNO). The Operator manages the cluster network.

You can specify the cluster network configuration for your OpenShift Container Platform cluster by setting the parameters for the defaultNetwork parameter in the CNO CR. The following CR displays the default configuration for the CNO and explains both the parameters you can configure and valid parameter values:

Cluster Network Operator CR
apiVersion: operator.openshift.io/v1
kind: Network
metadata:
  name: cluster
spec:
  clusterNetwork: (1)
  - cidr: 10.128.0.0/14
    hostPrefix: 23
  serviceNetwork: (1)
  - 172.30.0.0/16
  defaultNetwork: (2)
    ...
  kubeProxyConfig: (3)
    iptablesSyncPeriod: 30s (4)
    proxyArguments:
      iptables-min-sync-period: (5)
      - 30s
1 Specified in the install-config.yaml file.
2 Configures the software-defined networking (SDN) for the cluster network.
3 The parameters for this object specify the kube-proxy configuration. If you do not specify the parameter values, the Network Operator applies the displayed default parameter values.
4 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.
5 The minimum duration before refreshing iptables rules. This parameter ensures that the refresh does not happen too frequently. Valid suffixes include s, m, and h and are described in the Go time package

Configuration parameters for OpenShift SDN

The following YAML object describes the configuration parameters for OpenShift SDN:

defaultNetwork:
  type: OpenShiftSDN (1)
  openshiftSDNConfig: (2)
    mode: NetworkPolicy (3)
    mtu: 1450 (4)
    vxlanPort: 4789 (5)
1 Specified in the install-config.yaml file.
2 Specify only if you want to override part of the OpenShift SDN configuration.
3 Configures the network isolation mode for OpenShiftSDN. The allowed values are Multitenant, Subnet, or NetworkPolicy. The default value is NetworkPolicy.
4 MTU for the VXLAN overlay network. This value is normally configured automatically, but if the nodes in your cluster do not all use the same MTU, then you must set this explicitly to 50 less than the smallest node MTU value.
5 The port to use for all VXLAN packets. The default value is 4789. 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 VXLAN, since 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.

Cluster Network Operator example CR

A complete CR for the CNO is displayed in the following example:

Cluster Network Operator example CR
apiVersion: operator.openshift.io/v1
kind: Network
metadata:
  name: cluster
spec:
  clusterNetwork:
  - cidr: 10.128.0.0/14
    hostPrefix: 23
  serviceNetwork:
  - 172.30.0.0/16
  defaultNetwork:
    type: OpenShiftSDN
    openshiftSDNConfig:
      mode: NetworkPolicy
      mtu: 1450
      vxlanPort: 4789
  kubeProxyConfig:
    iptablesSyncPeriod: 30s
    proxyArguments:
      iptables-min-sync-period:
      - 30s

Deploy the cluster

You can install OpenShift Container Platform on a compatible cloud platform.

You can run the create cluster command of the installation program only once, during initial installation.

Prerequisites
  • Configure an account with the cloud platform that hosts your cluster.

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

Procedure
  1. Run the installation program:

    $ ./openshift-install create cluster --dir=<installation_directory> \ (1)
        --log-level=info (2)
    1 For <installation_directory>, specify the
    2 To view different installation details, specify warn, debug, or error instead of info.

    If the cloud provider account that you configured on your host does not have sufficient permissions to deploy the cluster, the installation process stops, and the missing permissions are displayed.

    When the cluster deployment completes, directions for accessing your cluster, including a link to its web console and credentials for the kubeadmin user, display in your terminal.

    The Ignition config files that the installation program generates contain certificates that expire after 24 hours. You must keep the cluster running for 24 hours in a non-degraded state to ensure that the first certificate rotation has finished.

    You must not delete the installation program or the files that the installation program creates. Both are required to delete the cluster.

Installing the CLI

You can install the CLI in order to interact with OpenShift Container Platform using a command-line interface.

If you installed an earlier version of oc, you cannot use it to complete all of the commands in OpenShift Container Platform 4.2. Download and install the new version of oc.

Procedure
  1. From the Infrastructure Provider page on the Red Hat OpenShift Cluster Manager site, navigate to the page for your installation type and click Download Command-line Tools.

  2. Click the folder for your operating system and architecture and click the compressed file.

    You can install oc on Linux, Windows, or macOS.

  3. Save the file to your file system.

  4. Extract the compressed file.

  5. Place it in a directory that is on your PATH.

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

$ oc <command>

Logging in to the cluster

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

Prerequisites
  • Deploy an OpenShift Container Platform cluster.

  • Install the oc CLI.

Procedure
  1. 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.
  2. Verify you can run oc commands successfully using the exported configuration:

    $ oc whoami
    system:admin
Next steps