Chapter 3. Installing a cluster on IBM Power in a restricted network

Procedure

1. If you are using DHCP to provide the IP networking configuration to your cluster nodes, configure your DHCP service.

   1. Add persistent IP addresses for the nodes to your DHCP server configuration. In your configuration, match the MAC address of the relevant network interface to the intended IP address for each node.

   2. When you use DHCP to configure IP addressing for the cluster machines, the machines also obtain the DNS server information through DHCP. Define the persistent DNS server address that is used by the cluster nodes through your DHCP server configuration.

      Note

      If you are not using a DHCP service, you must provide the IP networking configuration and the address of the DNS server to the nodes at RHCOS install time. These can be passed as boot arguments if you are installing from an ISO image. See the Installing RHCOS and starting the OpenShift Container Platform bootstrap process section for more information about static IP provisioning and advanced networking options.

   3. Define the hostnames of your cluster nodes in your DHCP server configuration. See the Setting the cluster node hostnames through DHCP section for details about hostname considerations.

      Note

      If you are not using a DHCP service, the cluster nodes obtain their hostname through a reverse DNS lookup.

2. Ensure that your network infrastructure provides the required network connectivity between the cluster components. See the Networking requirements for user-provisioned infrastructure section for details about the requirements.

3. Configure your firewall to enable the ports required for the OpenShift Container Platform cluster components to communicate. See Networking requirements for user-provisioned infrastructure section for details about the ports that are required.

   Important

   By default, port 1936 is accessible for an OpenShift Container Platform cluster, because each control plane node needs access to this port.

   Avoid using the Ingress load balancer to expose this port, because doing so might result in the exposure of sensitive information, such as statistics and metrics, related to Ingress Controllers.

4. Setup the required DNS infrastructure for your cluster.

   1. Configure DNS name resolution for the Kubernetes API, the application wildcard, the bootstrap machine, the control plane machines, and the compute machines.

   2. Configure reverse DNS resolution for the Kubernetes API, the bootstrap machine, the control plane machines, and the compute machines.

      See the User-provisioned DNS requirements section for more information about the OpenShift Container Platform DNS requirements.

5. Validate your DNS configuration.

   1. From your installation node, run DNS lookups against the record names of the Kubernetes API, the wildcard routes, and the cluster nodes. Validate that the IP addresses in the responses correspond to the correct components.

   2. From your installation node, run reverse DNS lookups against the IP addresses of the load balancer and the cluster nodes. Validate that the record names in the responses correspond to the correct components.

      See the Validating DNS resolution for user-provisioned infrastructure section for detailed DNS validation steps.

6. Provision the required API and application ingress load balancing infrastructure. See the Load balancing requirements for user-provisioned infrastructure section for more information about the requirements.

Procedure

1. From your installation node, run DNS lookups against the record names of the Kubernetes API, the wildcard routes, and the cluster nodes. Validate that the IP addresses contained in the responses correspond to the correct components.

   1. Perform a lookup against the Kubernetes API record name. Check that the result points to the IP address of the API load balancer:

      $ dig +noall +answer @<nameserver_ip> api.<cluster_name>.<base_domain> 1

      1

      Replace <nameserver_ip> with the IP address of the nameserver, <cluster_name> with your cluster name, and <base_domain> with your base domain name.

      Example output

      api.ocp4.example.com.		604800	IN	A	192.168.1.5

   2. Perform a lookup against the Kubernetes internal API record name. Check that the result points to the IP address of the API load balancer:

      $ dig +noall +answer @<nameserver_ip> api-int.<cluster_name>.<base_domain>

      Example output

      api-int.ocp4.example.com.		604800	IN	A	192.168.1.5

   3. Test an example *.apps.<cluster_name>.<base_domain> DNS wildcard lookup. All of the application wildcard lookups must resolve to the IP address of the application ingress load balancer:

      $ dig +noall +answer @<nameserver_ip> random.apps.<cluster_name>.<base_domain>

      Example output

      random.apps.ocp4.example.com.		604800	IN	A	192.168.1.5

      Note

      In the example outputs, the same load balancer is used for the Kubernetes API and application ingress traffic. In production scenarios, you can deploy the API and application ingress load balancers separately so that you can scale the load balancer infrastructure for each in isolation.

      You can replace random with another wildcard value. For example, you can query the route to the OpenShift Container Platform console:

      $ dig +noall +answer @<nameserver_ip> console-openshift-console.apps.<cluster_name>.<base_domain>

      Example output

      console-openshift-console.apps.ocp4.example.com. 604800 IN	A 192.168.1.5

   4. Run a lookup against the bootstrap DNS record name. Check that the result points to the IP address of the bootstrap node:

      $ dig +noall +answer @<nameserver_ip> bootstrap.<cluster_name>.<base_domain>

      Example output

      bootstrap.ocp4.example.com.		604800	IN	A	192.168.1.96

   5. Use this method to perform lookups against the DNS record names for the control plane and compute nodes. Check that the results correspond to the IP addresses of each node.

2. From your installation node, run reverse DNS lookups against the IP addresses of the load balancer and the cluster nodes. Validate that the record names contained in the responses correspond to the correct components.

   1. Perform a reverse lookup against the IP address of the API load balancer. Check that the response includes the record names for the Kubernetes API and the Kubernetes internal API:

      $ dig +noall +answer @<nameserver_ip> -x 192.168.1.5

      Example output

      5.1.168.192.in-addr.arpa. 604800	IN	PTR	api-int.ocp4.example.com. 1
      5.1.168.192.in-addr.arpa. 604800	IN	PTR	api.ocp4.example.com. 2

      1

      Provides the record name for the Kubernetes internal API.

      2

      Provides the record name for the Kubernetes API.

      Note

      A PTR record is not required for the OpenShift Container Platform application wildcard. No validation step is needed for reverse DNS resolution against the IP address of the application ingress load balancer.

   2. Perform a reverse lookup against the IP address of the bootstrap node. Check that the result points to the DNS record name of the bootstrap node:

      $ dig +noall +answer @<nameserver_ip> -x 192.168.1.96

      Example output

      96.1.168.192.in-addr.arpa. 604800	IN	PTR	bootstrap.ocp4.example.com.

   3. Use this method to perform reverse lookups against the IP addresses for the control plane and compute nodes. Check that the results correspond to the DNS record names of each node.

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_ed25519, of the new SSH key. If you have an existing key pair, ensure your public key is in the your ~/.ssh directory.

   Note

   If you plan to install an OpenShift Container Platform cluster that uses the RHEL cryptographic libraries that have been submitted to NIST for FIPS 140-2/140-3 Validation on only the x86_64, ppc64le, and s390x architectures, 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_ed25519.pub public key:

   $ cat ~/.ssh/id_ed25519.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.

   Note

   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

      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.

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_ed25519

   Example output

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

Procedure

1. 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.

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

   Note

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

3. 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.

Procedure

1. Change to the directory that contains the OpenShift Container Platform 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 compute nodes.

2. 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.

3. 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.

   Ignition config files are created for the bootstrap, control plane, and compute nodes in the installation directory. The kubeadmin-password and kubeconfig files are created in the ./<installation_directory>/auth directory:

   .
   ├── auth
   │   ├── kubeadmin-password
   │   └── kubeconfig
   ├── bootstrap.ign
   ├── master.ign
   ├── metadata.json
   └── worker.ign

Procedure

1. 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 v1.30.3 up
   INFO Waiting up to 30m0s for bootstrapping to complete...
   INFO It is now safe to remove the bootstrap resources

   The command succeeds when the Kubernetes API server signals that it has been bootstrapped on the control plane machines.

2. After the 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 bootstrap machine itself.

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

Procedure

1. Confirm that the cluster recognizes the machines:

   $ oc get nodes

   Example output

   NAME      STATUS    ROLES   AGE  VERSION
   master-0  Ready     master  63m  v1.30.3
   master-1  Ready     master  63m  v1.30.3
   master-2  Ready     master  64m  v1.30.3

   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.

2. 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.

3. 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. After 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.

4. 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
   ...

5. 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

6. 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  v1.30.3
   master-1  Ready     master  73m  v1.30.3
   master-2  Ready     master  74m  v1.30.3
   worker-0  Ready     worker  11m  v1.30.3
   worker-1  Ready     worker  11m  v1.30.3

   Note

   It can take a few minutes after approval of the server CSRs for the machines to transition to the Ready status.

Procedure

1. Watch the cluster components come online:

   $ watch -n5 oc get clusteroperators

   Example output

   NAME                                       VERSION   AVAILABLE   PROGRESSING   DEGRADED   SINCE
   authentication                             4.17.0    True        False         False      19m
   baremetal                                  4.17.0    True        False         False      37m
   cloud-credential                           4.17.0    True        False         False      40m
   cluster-autoscaler                         4.17.0    True        False         False      37m
   config-operator                            4.17.0    True        False         False      38m
   console                                    4.17.0    True        False         False      26m
   csi-snapshot-controller                    4.17.0    True        False         False      37m
   dns                                        4.17.0    True        False         False      37m
   etcd                                       4.17.0    True        False         False      36m
   image-registry                             4.17.0    True        False         False      31m
   ingress                                    4.17.0    True        False         False      30m
   insights                                   4.17.0    True        False         False      31m
   kube-apiserver                             4.17.0    True        False         False      26m
   kube-controller-manager                    4.17.0    True        False         False      36m
   kube-scheduler                             4.17.0    True        False         False      36m
   kube-storage-version-migrator              4.17.0    True        False         False      37m
   machine-api                                4.17.0    True        False         False      29m
   machine-approver                           4.17.0    True        False         False      37m
   machine-config                             4.17.0    True        False         False      36m
   marketplace                                4.17.0    True        False         False      37m
   monitoring                                 4.17.0    True        False         False      29m
   network                                    4.17.0    True        False         False      38m
   node-tuning                                4.17.0    True        False         False      37m
   openshift-apiserver                        4.17.0    True        False         False      32m
   openshift-controller-manager               4.17.0    True        False         False      30m
   openshift-samples                          4.17.0    True        False         False      32m
   operator-lifecycle-manager                 4.17.0    True        False         False      37m
   operator-lifecycle-manager-catalog         4.17.0    True        False         False      37m
   operator-lifecycle-manager-packageserver   4.17.0    True        False         False      32m
   service-ca                                 4.17.0    True        False         False      38m
   storage                                    4.17.0    True        False         False      37m

2. Configure the Operators that are not available.

Procedure

1. 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                             4.17.0    True        False         False      19m
   baremetal                                  4.17.0    True        False         False      37m
   cloud-credential                           4.17.0    True        False         False      40m
   cluster-autoscaler                         4.17.0    True        False         False      37m
   config-operator                            4.17.0    True        False         False      38m
   console                                    4.17.0    True        False         False      26m
   csi-snapshot-controller                    4.17.0    True        False         False      37m
   dns                                        4.17.0    True        False         False      37m
   etcd                                       4.17.0    True        False         False      36m
   image-registry                             4.17.0    True        False         False      31m
   ingress                                    4.17.0    True        False         False      30m
   insights                                   4.17.0    True        False         False      31m
   kube-apiserver                             4.17.0    True        False         False      26m
   kube-controller-manager                    4.17.0    True        False         False      36m
   kube-scheduler                             4.17.0    True        False         False      36m
   kube-storage-version-migrator              4.17.0    True        False         False      37m
   machine-api                                4.17.0    True        False         False      29m
   machine-approver                           4.17.0    True        False         False      37m
   machine-config                             4.17.0    True        False         False      36m
   marketplace                                4.17.0    True        False         False      37m
   monitoring                                 4.17.0    True        False         False      29m
   network                                    4.17.0    True        False         False      38m
   node-tuning                                4.17.0    True        False         False      37m
   openshift-apiserver                        4.17.0    True        False         False      32m
   openshift-controller-manager               4.17.0    True        False         False      30m
   openshift-samples                          4.17.0    True        False         False      32m
   operator-lifecycle-manager                 4.17.0    True        False         False      37m
   operator-lifecycle-manager-catalog         4.17.0    True        False         False      37m
   operator-lifecycle-manager-packageserver   4.17.0    True        False         False      32m
   service-ca                                 4.17.0    True        False         False      38m
   storage                                    4.17.0    True        False         False      37m

   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.

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

   1. 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
      ...

   2. 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.

3. Additional steps are required to enable multipathing. Do not enable multipathing during installation.

   See "Enabling multipathing with kernel arguments on RHCOS" in the Postinstallation machine configuration tasks documentation for more information.

4. Register your cluster on the Cluster registration page.