Installing a cluster on GCP in a restricted network - Installing on GCP | Installing

Prerequisites
About installations in restricted networks
- Additional limits
Generating a key pair for cluster node SSH access
Creating the installation configuration file
- Installation configuration parameters

In OKD 4.11, you can install a cluster on Google Cloud Platform (GCP) in a restricted network by creating an internal mirror of the installation release content on an existing Google Virtual Private Cloud (VPC).

You can install an OKD cluster by using mirrored installation release content, but your cluster will require internet access to use the GCP APIs.

Prerequisites

You reviewed details about the OKD installation and update processes.
You read the documentation on selecting a cluster installation method and preparing it for users.
You configured a GCP project to host the cluster.
You mirrored the images for a disconnected installation to your registry and obtained the imageContentSources data for your version of OKD.

Because the installation media is on the mirror host, you can use that computer to complete all installation steps.
You have an existing VPC in GCP. While installing a cluster in a restricted network that uses installer-provisioned infrastructure, you cannot use the installer-provisioned VPC. You must use a user-provisioned VPC that satisfies one of the following requirements:
- Contains the mirror registry
- Has firewall rules or a peering connection to access the mirror registry hosted elsewhere
If you use a firewall, you configured it to allow the sites that your cluster requires access to. While you might need to grant access to more sites, you must grant access to *.googleapis.com and accounts.google.com.
If the cloud identity and access management (IAM) APIs are not accessible in your environment, or if you do not want to store an administrator-level credential secret in the kube-system namespace, you can manually create and maintain IAM credentials.

About installations in restricted networks

In OKD 4.11, 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 image registry and contains the installation media. You can create this registry on a mirror host, which can access both the internet and your closed network, or by using other methods that meet your restrictions.

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.

Generating a key pair for cluster node SSH access

During an OKD installation, you can provide an SSH public key to the installation program. The key is passed to the Fedora CoreOS (FCOS) nodes through their Ignition config files and is used to authenticate SSH access to the nodes. The key is added to the ~/.ssh/authorized_keys list for the core user on each node, which enables password-less authentication.

After the key is passed to the nodes, you can use the key pair to SSH in to the FCOS nodes as the user core. To access the nodes through SSH, the private key identity must be managed by SSH for your local user.

If you want to SSH in to your cluster nodes to perform installation debugging or disaster recovery, you must provide the SSH public key during the installation process. The ./openshift-install gather command also requires the SSH public key to be in place on the cluster nodes.

Do not skip this procedure in production environments, where disaster recovery and debugging is required.

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

On clusters running Fedora CoreOS (FCOS), the SSH keys specified in the Ignition config files are written to the /home/core/.ssh/authorized_keys.d/core file. However, the Machine Config Operator manages SSH keys in the /home/core/.ssh/authorized_keys file and configures sshd to ignore the /home/core/.ssh/authorized_keys.d/core file. As a result, newly provisioned OKD nodes are not accessible using SSH until the Machine Config Operator reconciles the machine configs with the authorized_keys file. After you can access the nodes using SSH, you can delete the /home/core/.ssh/authorized_keys.d/core file.

Procedure

If you do not have an existing SSH key pair on your local machine to use for authentication onto your cluster nodes, create one. For example, on a computer that uses a Linux operating system, run the following command:

$ ssh-keygen -t ed25519 -N '' -f <path>/<file_name> (1)

1	Specify the path and file name, such as `~/.ssh/id_ed25519`, of the new SSH key. If you have an existing key pair, ensure your public key is in the your `~/.ssh` directory.

If you plan to install an OKD cluster that uses fips validated or 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.

View the public SSH key:
```
$ cat <path>/<file_name>.pub
```
For example, run the following to view the ~/.ssh/id_ed25519.pub public key:
```
$ cat ~/.ssh/id_ed25519.pub
```
Add the SSH private key identity to the SSH agent for your local user, if it has not already been added. SSH agent management of the key is required for password-less SSH authentication onto your cluster nodes, or if you want to use the ./openshift-install gather command.

On some distributions, default SSH private key identities such as ~/.ssh/id_rsa and ~/.ssh/id_dsa are managed automatically.
1. If the ssh-agent process is not already running for your local user, start it as a background task:
  $ eval "$(ssh-agent -s)"
  Example output
  Agent pid 31874
  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)
```
1 Specify the path and file name for your SSH private key, such as ~/.ssh/id_ed25519
Example output
```
Identity added: /home/<you>/<path>/<file_name> (<computer_name>)
```
Set the GOOGLE_APPLICATION_CREDENTIALS environment variable to the full path to your service account private key file.
```
$ export GOOGLE_APPLICATION_CREDENTIALS="<your_service_account_file>"
```
Verify that the credentials were applied.
```
$ gcloud auth list
```

Next steps

When you install OKD, provide the SSH public key to the installation program.

Creating the installation configuration file

You can customize the OKD cluster you install on Google Cloud Platform (GCP).

Prerequisites

Obtain the OKD installation program and the pull secret for your cluster. For a restricted network installation, these files are on your mirror host.
Have the imageContentSources values that were generated during mirror registry creation.
Obtain the contents of the certificate for your mirror registry.
Obtain service principal permissions at the subscription level.

Procedure

Create the install-config.yaml file.
1. Change to the directory that contains the installation program and 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.
  
  When specifying the directory:
  - Verify that the directory has the execute permission. This permission is required to run Terraform binaries under the installation directory.
  - Use an empty directory. Some installation assets, such as bootstrap X.509 certificates, have short expiration intervals, therefore 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 OKD 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 OKD clusters on which you want to perform installation debugging or disaster recovery, 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.
  8. Paste the pull secret from the Red Hat OpenShift Cluster Manager. This field is optional.
Edit the install-config.yaml file to give the additional information that is required for an installation in a restricted network.
1. Update the pullSecret value to contain the authentication information for your registry:
  pullSecret: '{"auths":{"<mirror_host_name>:5000": {"auth": "<credentials>","email": "you@example.com"}}}'
  For <mirror_host_name>, specify the registry domain name that you specified in the certificate for your mirror registry, and for <credentials>, specify the base64-encoded user name and password for your mirror registry.
2. Add the additionalTrustBundle parameter and value.
  additionalTrustBundle: | -----BEGIN CERTIFICATE----- ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ -----END CERTIFICATE-----
  The value must be the contents of the certificate file that you used for your mirror registry. The certificate file can be an existing, trusted certificate authority, or the self-signed certificate that you generated for the mirror registry.
3. Define the network and subnets for the VPC to install the cluster in under the parent platform.gcp field:
  network: <existing_vpc> controlPlaneSubnet: <control_plane_subnet> computeSubnet: <compute_subnet>
  For platform.gcp.network, specify the name for the existing Google VPC. For platform.gcp.controlPlaneSubnet and platform.gcp.computeSubnet, specify the existing subnets to deploy the control plane machines and compute machines, respectively.
4. Add the image content resources, which resemble the following YAML excerpt:
  imageContentSources: - mirrors: - <mirror_host_name>:5000/<repo_name>/release source: quay.io/openshift-release-dev/ocp-release - mirrors: - <mirror_host_name>:5000/<repo_name>/release source: registry.redhat.io/ocp/release
  For these values, use the imageContentSources that you recorded during mirror registry creation.
Make any other modifications to the install-config.yaml file that you require. You can find more information about the available parameters in the Installation configuration parameters section.
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 OKD 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.

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

Required configuration parameters

Required installation configuration parameters are described in the following table:

Table 1. 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 OKD 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: `alibabacloud`, `aws`, `baremetal`, `azure`, `gcp`, `ibmcloud`, `nutanix`, `openstack`, `ovirt`, `vsphere`, or `{}`. For additional information about `platform.<platform>` parameters, consult the table for your specific platform that follows.	Object

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.

Globalnet is not supported with Red Hat OpenShift Data Foundation disaster recovery solutions. For regional disaster recovery scenarios, ensure that you use a nonoverlapping range of private IP addresses for the cluster and service networks in each cluster.

Parameter Description Values

networking

The configuration for the cluster network.

Object

You cannot modify parameters specified by the networking object after installation.

networking.networkType

The cluster network provider Container Network Interface (CNI) cluster network provider to install.

Either OpenShiftSDN or OVNKubernetes. The default value is OVNKubernetes.

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.

Set the networking.machineNetwork to match the CIDR that the preferred NIC resides in.

Optional configuration parameters

Optional installation configuration parameters are described in the following table:

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

capabilities

Controls the installation of optional core cluster components. You can reduce the footprint of your OKD cluster by disabling optional components.

String array

capabilities.baselineCapabilitySet

Selects an initial set of optional capabilities to enable. Valid values are None, v4.11 and vCurrent. v4.11 enables the baremetal Operator, the marketplace Operator, and the openshift-samples content. vCurrent installs the recommended set of capabilities for the current version of OKD. The default value is vCurrent.

String

capabilities.additionalEnabledCapabilities

Extends the set of optional capabilities beyond what you specify in baselineCapabilitySet. Valid values are baremetal, marketplace and openshift-samples. You may specify multiple capabilities in this parameter.

String array

cgroupsV2

Enables Linux control groups version 2 (cgroups v2) on specific nodes in your cluster. The OKD process for enabling cgroups v2 disables all cgroup version 1 controllers and hierarchies. The OKD cgroups version 2 feature is in Developer Preview and is not supported by Red Hat at this time.

true

compute

The configuration for the machines that comprise the compute nodes.

Array of MachinePool objects.

compute.architecture

Determines the instruction set architecture of the machines in the pool. Currently, clusters with varied architectures are not supported. All pools must specify the same architecture. Valid values are 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.

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.

alibabacloud, aws, azure, gcp, ibmcloud, nutanix, 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.

controlPlane.architecture

String