Installing a private cluster on GCP

In OKD version 4.10, you can install a private cluster into an existing VPC on Google Cloud Platform (GCP). The installation program provisions the rest of the required infrastructure, which you can further customize. To customize the installation, you modify parameters in the install-config.yaml file before you install the cluster.

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.

• If you use a firewall, you configured it to allow the sites that your cluster requires access to.

• 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.

Private clusters

You can deploy a private OKD cluster that does not expose external endpoints. Private clusters are accessible from only an internal network and are not visible to the internet.

By default, OKD is provisioned to use publicly-accessible DNS and endpoints. A private cluster sets the DNS, Ingress Controller, and API server to private when you deploy your cluster. This means that the cluster resources are only accessible from your internal network and are not visible to the internet.

To deploy a private cluster, you must:

• Use existing networking that meets your requirements. Your cluster resources might be shared between other clusters on the network.

• Deploy from a machine that has access to:

  • The API services for the cloud to which you provision.

  • The hosts on the network that you provision.

  • The internet to obtain installation media.

You can use any machine that meets these access requirements and follows your company’s guidelines. For example, this machine can be a bastion host on your cloud network or a machine that has access to the network through a VPN.

Private clusters in GCP

To create a private cluster on Google Cloud Platform (GCP), you must provide an existing private VPC and subnets to host the cluster. The installation program must also be able to resolve the DNS records that the cluster requires. The installation program configures the Ingress Operator and API server for only internal traffic.

The cluster still requires access to internet to access the GCP APIs.

The following items are not required or created when you install a private cluster:

• Public subnets

• Public network load balancers, which support public ingress

• A public DNS zone that matches the baseDomain for the cluster

The installation program does use the baseDomain that you specify to create a private DNS zone and the required records for the cluster. The cluster is configured so that the Operators do not create public records for the cluster and all cluster machines are placed in the private subnets that you specify.

Because it is not possible to limit access to external load balancers based on source tags, the private cluster uses only internal load balancers to allow access to internal instances.

The internal load balancer relies on instance groups rather than the target pools that the network load balancers use. The installation program creates instance groups for each zone, even if there is no instance in that group.

• The cluster IP address is internal only.

• One forwarding rule manages both the Kubernetes API and machine config server ports.

• The backend service is comprised of each zone’s instance group and, while it exists, the bootstrap instance group.

• The firewall uses a single rule that is based on only internal source ranges.

Limitations

No health check for the Machine config server, /healthz, runs because of a difference in load balancer functionality. Two internal load balancers cannot share a single IP address, but two network load balancers can share a single external IP address. Instead, the health of an instance is determined entirely by the /readyz check on port 6443.

About using a custom VPC

In OKD 4.10, you can deploy a cluster into an existing VPC in Google Cloud Platform (GCP). If you do, you must also use existing subnets within the VPC and routing rules.

By deploying OKD into an existing GCP VPC, you might be able to avoid limit constraints in new accounts or more easily abide by the operational constraints that your company’s guidelines set. This is a good option to use if you cannot obtain the infrastructure creation permissions that are required to create the VPC yourself.

Requirements for using your VPC

The installation program will no longer create the following components:

• VPC

• Subnets

• Cloud router

• Cloud NAT

• NAT IP addresses

If you use a custom VPC, you must correctly configure it and its subnets for the installation program and the cluster to use. The installation program cannot subdivide network ranges for the cluster to use, set route tables for the subnets, or set VPC options like DHCP, so you must do so before you install the cluster.

Your VPC and subnets must meet the following characteristics:

• The VPC must be in the same GCP project that you deploy the OKD cluster to.

• To allow access to the internet from the control plane and compute machines, you must configure cloud NAT on the subnets to allow egress to it. These machines do not have a public address. Even if you do not require access to the internet, you must allow egress to the VPC network to obtain the installation program and images. Because multiple cloud NATs cannot be configured on the shared subnets, the installation program cannot configure it.

To ensure that the subnets that you provide are suitable, the installation program confirms the following data:

• All the subnets that you specify exist and belong to the VPC that you specified.

• The subnet CIDRs belong to the machine CIDR.

• You must provide a subnet to deploy the cluster control plane and compute machines to. You can use the same subnet for both machine types.

If you destroy a cluster that uses an existing VPC, the VPC is not deleted.

Division of permissions

Starting with OKD 4.3, you do not need all of the permissions that are required for an installation program-provisioned infrastructure cluster to deploy a cluster. This change mimics the division of permissions that you might have at your company: some individuals can create different resources in your clouds than others. For example, you might be able to create application-specific items, like instances, buckets, and load balancers, but not networking-related components such as VPCs, subnets, or Ingress rules.

The GCP credentials that you use when you create your cluster do not need the networking permissions that are required to make VPCs and core networking components within the VPC, such as subnets, routing tables, internet gateways, NAT, and VPN. You still need permission to make the application resources that the machines within the cluster require, such as load balancers, security groups, storage, and nodes.

Isolation between clusters

If you deploy OKD to an existing network, the isolation of cluster services is preserved by firewall rules that reference the machines in your cluster by the cluster’s infrastructure ID. Only traffic within the cluster is allowed.

If you deploy multiple clusters to the same VPC, the following components might share access between clusters:

• The API, which is globally available with an external publishing strategy or available throughout the network in an internal publishing strategy

• Debugging tools, such as ports on VM instances that are open to the machine CIDR for SSH and ICMP access

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.

Procedure

1. 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_rsa, 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 / 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.

2. View the public SSH key:

   $ cat <path>/<file_name>.pub

   For example, run the following to view the ~/.ssh/id_rsa.pub public key:

   $ cat ~/.ssh/id_rsa.pub

3. 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.

4. 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_rsa

   Example output

   Identity added: /home/<you>/<path>/<file_name> (<computer_name>)

5. 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>"

6. Verify that the credentials were applied.

   $ gcloud auth list

Next steps

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

Obtaining the installation program

Before you install OKD, 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

1. Download installer from https://github.com/openshift/okd/releases

   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.

   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 OKD uninstallation procedures for your specific cloud provider.

2. 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

3. 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 OKD components.

   Using a pull secret from the Red Hat OpenShift Cluster Manager is not required. You can use a pull secret for another private registry. Or, if you do not need the cluster to pull images from a private registry, you can use {"auths":{"fake":{"auth":"aWQ6cGFzcwo="}}} as the pull secret when prompted during the installation.

   If you do not use the pull secret from the Red Hat OpenShift Cluster Manager:

   • Red Hat Operators are not available.

   • The Telemetry and Insights operators do not send data to Red Hat.

   • Content from the Red Hat Container Catalog registry, such as image streams and Operators, are not available.

Manually creating the installation configuration file

For installations of a private OKD cluster that are only accessible from an internal network and are not visible to the internet, you must manually generate your installation configuration file.

Prerequisites

• You have an SSH public key on your local machine to provide to the installation program. The key will be used for SSH authentication onto your cluster nodes for debugging and disaster recovery.

• You have obtained the OKD installation program and the pull secret for your cluster.

Procedure

1. Create an installation directory to store your required installation assets in:

   $ mkdir <installation_directory>

   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 OKD version.

2. Customize the sample install-config.yaml file template that is provided and save it in the <installation_directory>.

   You must name this configuration file install-config.yaml.

   For some platform types, you can alternatively run ./openshift-install create install-config —dir <installation_directory> to generate an install-config.yaml file. You can provide details about your cluster configuration at the prompts.

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 next step of the installation process. 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.

Required configuration parameters

Required installation configuration parameters are described in the following table:

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.

networking:
  clusterNetwork:
  - cidr: 10.128.0.0/14
    hostPrefix: 23

networking:
  serviceNetwork:
   - 172.30.0.0/16

networking:
  machineNetwork:
  - cidr: 10.0.0.0/16

Optional configuration parameters

Optional installation configuration parameters are described in the following table:

sshKey:
  <key1>
  <key2>
  <key3>

Additional Google Cloud Platform (GCP) configuration parameters

Additional GCP configuration parameters are described in the following table:

Minimum resource requirements for cluster installation

Each cluster machine must meet the following minimum requirements:

1. One vCPU 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 = vCPUs.

2. OKD 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.

3. As with all user-provisioned installations, if you choose to use Fedora compute machines in your cluster, you take responsibility for all operating system life cycle management and maintenance, including performing system updates, applying patches, and completing all other required tasks. Use of Fedora 7 compute machines is deprecated and planned for removal in a future release of OKD 4.

Sample customized install-config.yaml file for GCP

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

apiVersion: v1
baseDomain: example.com (1)
controlPlane:  (2) (3)
  hyperthreading: Enabled (4)
  name: master
  platform:
    gcp:
      type: n2-standard-4
      zones:
      - us-central1-a
      - us-central1-c
      osDisk:
        diskType: pd-ssd
        diskSizeGB: 1024
        encryptionKey: (5)
          kmsKey:
            name: worker-key
            keyRing: test-machine-keys
            location: global
            projectID: project-id
  replicas: 3
compute:  (2) (3)
- hyperthreading: Enabled (4)
  name: worker
  platform:
    gcp:
      type: n2-standard-4
      zones:
      - us-central1-a
      - us-central1-c
      osDisk:
        diskType: pd-standard
        diskSizeGB: 128
        encryptionKey: (5)
          kmsKey:
            name: worker-key
            keyRing: test-machine-keys
            location: global
            projectID: project-id
  replicas: 3
metadata:
  name: test-cluster (1)
networking:
  clusterNetwork:
  - cidr: 10.128.0.0/14
    hostPrefix: 23
  machineNetwork:
  - cidr: 10.0.0.0/16
  networkType: OVNKubernetes
  serviceNetwork:
  - 172.30.0.0/16
platform:
  gcp:
    projectID: openshift-production (1)
    region: us-central1 (1)
    network: existing_vpc (6)
    controlPlaneSubnet: control_plane_subnet (7)
    computeSubnet: compute_subnet (8)
pullSecret: '{"auths": ...}' (1)
sshKey: ssh-ed25519 AAAA... (9)
publish: Internal (10)

Create an Ingress Controller with global access on GCP

You can create an Ingress Controller that has global access to a Google Cloud Platform (GCP) cluster. Global access is only available to Ingress Controllers using internal load balancers.

Prerequisites

• You created the install-config.yaml and complete any modifications to it.

Procedure

Create an Ingress Controller with global access on a new GCP cluster.

1. Change to the directory that contains the installation program and create a manifest file:

   $ ./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.

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

   $ ls <installation_directory>/manifests/cluster-ingress-default-ingresscontroller.yaml

   Example output

   cluster-ingress-default-ingresscontroller.yaml

2. Open the cluster-ingress-default-ingresscontroller.yaml file in an editor and enter a custom resource (CR) that describes the Operator configuration you want:

   Sample clientAccess configuration to Global

     spec:
       endpointPublishingStrategy:
         loadBalancer:
           providerParameters:
             gcp:
               clientAccess: Global (1)
             type: GCP
           scope: Internal          (2)
         type: LoadBalancerService

   1	Set gcp.clientAccess to Global.
   2	Global access is only available to Ingress Controllers using internal load balancers.

Additional resources

• Enabling customer-managed encryption keys for a machine set

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 OKD cluster to use a proxy by configuring the proxy settings in the install-config.yaml file.

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.

  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

1. 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 that contains one or more additional CA certificates that are required for proxying HTTPS connections. The Cluster Network Operator then creates a trusted-ca-bundle config map that merges these contents with the Fedora CoreOS (FCOS) trust bundle, and this config map is referenced in the trustedCA field of the Proxy object. The additionalTrustBundle field is required unless the proxy’s identity certificate is signed by an authority from the FCOS trust bundle.

   The installation program does not support the proxy readinessEndpoints field.

2. Save the file and reference it when installing OKD.

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.

Deploying the cluster

You can install OKD on a compatible cloud platform.

Prerequisites

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

• Obtain the OKD installation program and the pull secret for your cluster.

Procedure

1. Change to the directory that contains the installation program and initialize the cluster deployment:

   $ ./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.

   Example output

   ...
   INFO Install complete!
   INFO To access the cluster as the system:admin user when using 'oc', run 'export KUBECONFIG=/home/myuser/install_dir/auth/kubeconfig'
   INFO Access the OpenShift web-console here: https://console-openshift-console.apps.mycluster.example.com
   INFO Login to the console with user: "kubeadmin", and password: "4vYBz-Ee6gm-ymBZj-Wt5AL"
   INFO Time elapsed: 36m22s

   The cluster access and credential information also outputs to <installation_directory>/.openshift_install.log when an installation succeeds.

   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.

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

Installing the OpenShift CLI by downloading the binary

You can install the OpenShift CLI (oc) to interact with OKD from a command-line interface. You can install oc on Linux, Windows, or macOS.

Installing the OpenShift CLI on Linux

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

Procedure

1. Navigate to https://mirror.openshift.com/pub/openshift-v4/clients/oc/latest/ and choose the folder for your operating system and architecture.

2. Download oc.tar.gz.

3. Unpack the archive:

   $ tar xvzf <file>

4. 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>

Installing the OpenShift CLI on Windows

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

Procedure

1. Navigate to https://mirror.openshift.com/pub/openshift-v4/clients/oc/latest/ and choose the folder for your operating system and architecture.

2. Download oc.zip.

3. Unzip the archive with a ZIP program.

4. 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>

Installing the OpenShift CLI on macOS

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

Procedure

1. Navigate to https://mirror.openshift.com/pub/openshift-v4/clients/oc/latest/ and choose the folder for your operating system and architecture.

2. Download oc.tar.gz.

3. Unpack and unzip the archive.

4. 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>

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 OKD installation.

Prerequisites

• You deployed an OKD cluster.

• You installed 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

   Example output

   system:admin

Additional resources

• See Accessing the web console for more details about accessing and understanding the OKD web console.

Additional resources

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

Next steps

• Customize your cluster.

• If necessary, you can opt out of remote health reporting.