Post-installation configuration

Procedure

1. Log in to your Azure account:

   $ az login

2. Create a storage account and upload the arm64 virtual hard disk (VHD) to your storage account. The OpenShift Container Platform installation program creates a resource group, however, the boot image can also be uploaded to a custom named resource group:

   $ az storage account create -n ${STORAGE_ACCOUNT_NAME} -g ${RESOURCE_GROUP} -l westus --sku Standard_LRS 1

   1

   The westus object is an example region.

3. Create a storage container using the storage account you generated:

   $ az storage container create -n ${CONTAINER_NAME} --account-name ${STORAGE_ACCOUNT_NAME}

4. You must use the OpenShift Container Platform installation program JSON file to extract the URL and aarch64 VHD name:

   1. Extract the URL field and set it to RHCOS_VHD_ORIGIN_URL as the file name by running the following command:

      $ RHCOS_VHD_ORIGIN_URL=$(oc -n openshift-machine-config-operator get configmap/coreos-bootimages -o jsonpath='{.data.stream}' | jq -r '.architectures.aarch64."rhel-coreos-extensions"."azure-disk".url')

   2. Extract the aarch64 VHD name and set it to BLOB_NAME as the file name by running the following command:

      $ BLOB_NAME=rhcos-$(oc -n openshift-machine-config-operator get configmap/coreos-bootimages -o jsonpath='{.data.stream}' | jq -r '.architectures.aarch64."rhel-coreos-extensions"."azure-disk".release')-azure.aarch64.vhd

5. Generate a shared access signature (SAS) token. Use this token to upload the RHCOS VHD to your storage container with the following commands:

   $ end=`date -u -d "30 minutes" '+%Y-%m-%dT%H:%MZ'`

   $ sas=`az storage container generate-sas -n ${CONTAINER_NAME} --account-name ${STORAGE_ACCOUNT_NAME} --https-only --permissions dlrw --expiry $end -o tsv`

6. Copy the RHCOS VHD into the storage container:

   $ az storage blob copy start --account-name ${STORAGE_ACCOUNT_NAME} --sas-token "$sas" \
    --source-uri "${RHCOS_VHD_ORIGIN_URL}" \
    --destination-blob "${BLOB_NAME}" --destination-container ${CONTAINER_NAME}

   You can check the status of the copying process with the following command:

   $ az storage blob show -c ${CONTAINER_NAME} -n ${BLOB_NAME} --account-name ${STORAGE_ACCOUNT_NAME} | jq .properties.copy

   Example output

   {
    "completionTime": null,
    "destinationSnapshot": null,
    "id": "1fd97630-03ca-489a-8c4e-cfe839c9627d",
    "incrementalCopy": null,
    "progress": "17179869696/17179869696",
    "source": "https://rhcos.blob.core.windows.net/imagebucket/rhcos-411.86.202207130959-0-azure.aarch64.vhd",
    "status": "success", 1
    "statusDescription": null
   }

   1

   If the status parameter displays the success object, the copying process is complete.

7. Create an image gallery using the following command:

   $ az sig create --resource-group ${RESOURCE_GROUP} --gallery-name ${GALLERY_NAME}

   Use the image gallery to create an image definition. In the following example command, rhcos-arm64 is the name of the image definition.

   $ az sig image-definition create --resource-group ${RESOURCE_GROUP} --gallery-name ${GALLERY_NAME} --gallery-image-definition rhcos-arm64 --publisher RedHat --offer arm --sku arm64 --os-type linux --architecture Arm64 --hyper-v-generation V2

8. To get the URL of the VHD and set it to RHCOS_VHD_URL as the file name, run the following command:

   $ RHCOS_VHD_URL=$(az storage blob url --account-name ${STORAGE_ACCOUNT_NAME} -c ${CONTAINER_NAME} -n "${BLOB_NAME}" -o tsv)

9. Use the RHCOS_VHD_URL file, your storage account, resource group, and image gallery to create an image version. In the following example, 1.0.0 is the image version.

   $ az sig image-version create --resource-group ${RESOURCE_GROUP} --gallery-name ${GALLERY_NAME} --gallery-image-definition rhcos-arm64 --gallery-image-version 1.0.0 --os-vhd-storage-account ${STORAGE_ACCOUNT_NAME} --os-vhd-uri ${RHCOS_VHD_URL}

10. Your arm64 boot image is now generated. You can access the ID of your image with the following command:

    $ az sig image-version show -r $GALLERY_NAME -g $RESOURCE_GROUP -i rhcos-arm64 -e 1.0.0

    The following example image ID is used in the recourseID parameter of the compute machine set:

    Example resourceID

    /resourceGroups/${RESOURCE_GROUP}/providers/Microsoft.Compute/galleries/${GALLERY_NAME}/images/rhcos-arm64/versions/1.0.0

Verification

1. Verify that the new ARM64 machines are running by entering the following command:

   $ oc get machineset -n openshift-machine-api

   Example output

   NAME                                                DESIRED  CURRENT  READY  AVAILABLE  AGE
   <infrastructure_id>-arm64-machine-set-0                   2        2      2          2  10m

2. You can check that the nodes are ready and scheduable with the following command:

   $ oc get nodes

Verification

1. View the list of compute machine sets by entering the following command:

   $ oc get machineset -n openshift-machine-api

   You can then see your created ARM64 machine set.

   Example output

   NAME                                                DESIRED  CURRENT  READY  AVAILABLE  AGE
   <infrastructure_id>-aws-arm64-machine-set-0                   2        2      2          2  10m

2. You can check that the nodes are ready and scheduable with the following command:

   $ oc get nodes

Procedure

1. Extract the Ignition config file from the cluster by running the following command:

   $ oc extract -n openshift-machine-api secret/worker-user-data-managed --keys=userData --to=- > worker.ign

2. Upload the worker.ign Ignition config file you exported from your cluster to your HTTP server. Note the URLs of these files.

3. You can validate that the ignition files are available on the URLs. The following example gets the Ignition config files for the compute node:

   $ curl -k http://<HTTP_server>/worker.ign

4. You can access the ISO image for booting your new machine by running to following command:

   RHCOS_VHD_ORIGIN_URL=$(oc -n openshift-machine-config-operator get configmap/coreos-bootimages -o jsonpath='{.data.stream}' | jq -r '.architectures.<architecture>.artifacts.metal.formats.iso.disk.location')

5. Use the ISO file to install RHCOS on more compute machines. Use the same method that you used when you created machines before you installed the cluster:

   • Burn the ISO image to a disk and boot it directly.
   • Use ISO redirection with a LOM interface.

6. Boot the RHCOS ISO image without specifying any options, or interrupting the live boot sequence. Wait for the installer to boot into a shell prompt in the RHCOS live environment.

   Note

   You can interrupt the RHCOS installation boot process to add kernel arguments. However, for this ISO procedure you must use the coreos-installer command as outlined in the following steps, instead of adding kernel arguments.

7. Run the coreos-installer command and specify the options that meet your installation requirements. At a minimum, you must specify the URL that points to the Ignition config file for the node type, and the device that you are installing to:

   $ sudo coreos-installer install --ignition-url=http://<HTTP_server>/<node_type>.ign <device> --ignition-hash=sha512-<digest> 12

   1

   You must run the coreos-installer command by using sudo, because the core user does not have the required root privileges to perform the installation.

   2

   The --ignition-hash option is required when the Ignition config file is obtained through an HTTP URL to validate the authenticity of the Ignition config file on the cluster node. <digest> is the Ignition config file SHA512 digest obtained in a preceding step.

   Note

   If you want to provide your Ignition config files through an HTTPS server that uses TLS, you can add the internal certificate authority (CA) to the system trust store before running coreos-installer.

   The following example initializes a bootstrap node installation to the /dev/sda device. The Ignition config file for the bootstrap node is obtained from an HTTP web server with the IP address 192.168.1.2:

   $ sudo coreos-installer install --ignition-url=http://192.168.1.2:80/installation_directory/bootstrap.ign /dev/sda --ignition-hash=sha512-a5a2d43879223273c9b60af66b44202a1d1248fc01cf156c46d4a79f552b6bad47bc8cc78ddf0116e80c59d2ea9e32ba53bc807afbca581aa059311def2c3e3b

8. Monitor the progress of the RHCOS installation on the console of the machine.

   Important

   Ensure that the installation is successful on each node before commencing with the OpenShift Container Platform installation. Observing the installation process can also help to determine the cause of RHCOS installation issues that might arise.

9. Continue to create more compute machines for your cluster.

Procedure

1. Confirm that your PXE or iPXE installation for the RHCOS images is correct.

   • For PXE:

     DEFAULT pxeboot
     TIMEOUT 20
     PROMPT 0
     LABEL pxeboot
         KERNEL http://<HTTP_server>/rhcos-<version>-live-kernel-<architecture> 1
         APPEND initrd=http://<HTTP_server>/rhcos-<version>-live-initramfs.<architecture>.img coreos.inst.install_dev=/dev/sda coreos.inst.ignition_url=http://<HTTP_server>/worker.ign coreos.live.rootfs_url=http://<HTTP_server>/rhcos-<version>-live-rootfs.<architecture>.img 2

     1

     Specify the location of the live kernel file that you uploaded to your HTTP server.

     2

     Specify locations of the RHCOS files that you uploaded to your HTTP server. The initrd parameter value is the location of the live initramfs file, the coreos.inst.ignition_url parameter value is the location of the worker Ignition config file, and the coreos.live.rootfs_url parameter value is the location of the live rootfs file. The coreos.inst.ignition_url and coreos.live.rootfs_url parameters only support HTTP and HTTPS.

     Note

     This configuration does not enable serial console access on machines with a graphical console. To configure a different console, add one or more console= arguments to the APPEND line. For example, add console=tty0 console=ttyS0 to set the first PC serial port as the primary console and the graphical console as a secondary console. For more information, see How does one set up a serial terminal and/or console in Red Hat Enterprise Linux?.

   • For iPXE (x86_64 + aarch64):

     kernel http://<HTTP_server>/rhcos-<version>-live-kernel-<architecture> initrd=main coreos.live.rootfs_url=http://<HTTP_server>/rhcos-<version>-live-rootfs.<architecture>.img coreos.inst.install_dev=/dev/sda coreos.inst.ignition_url=http://<HTTP_server>/worker.ign 1 2
     initrd --name main http://<HTTP_server>/rhcos-<version>-live-initramfs.<architecture>.img 3
     boot

     1

     Specify the locations of the RHCOS files that you uploaded to your HTTP server. The kernel parameter value is the location of the kernel file, the initrd=main argument is needed for booting on UEFI systems, the coreos.live.rootfs_url parameter value is the location of the rootfs file, and the coreos.inst.ignition_url parameter value is the location of the worker Ignition config file.

     2

     If you use multiple NICs, specify a single interface in the ip option. For example, to use DHCP on a NIC that is named eno1, set ip=eno1:dhcp.

     3

     Specify the location of the initramfs file that you uploaded to your HTTP server.

     Note

     This configuration does not enable serial console access on machines with a graphical console To configure a different console, add one or more console= arguments to the kernel line. For example, add console=tty0 console=ttyS0 to set the first PC serial port as the primary console and the graphical console as a secondary console. For more information, see How does one set up a serial terminal and/or console in Red Hat Enterprise Linux? and "Enabling the serial console for PXE and ISO installation" in the "Advanced RHCOS installation configuration" section.

     Note

     To network boot the CoreOS kernel on aarch64 architecture, you need to use a version of iPXE build with the IMAGE_GZIP option enabled. See IMAGE_GZIP option in iPXE.

   • For PXE (with UEFI and GRUB as second stage) on aarch64:

     menuentry 'Install CoreOS' {
         linux rhcos-<version>-live-kernel-<architecture>  coreos.live.rootfs_url=http://<HTTP_server>/rhcos-<version>-live-rootfs.<architecture>.img coreos.inst.install_dev=/dev/sda coreos.inst.ignition_url=http://<HTTP_server>/worker.ign 1 2
         initrd rhcos-<version>-live-initramfs.<architecture>.img 3
     }

     1

     Specify the locations of the RHCOS files that you uploaded to your HTTP/TFTP server. The kernel parameter value is the location of the kernel file on your TFTP server. The coreos.live.rootfs_url parameter value is the location of the rootfs file, and the coreos.inst.ignition_url parameter value is the location of the worker Ignition config file on your HTTP Server.

     2

     If you use multiple NICs, specify a single interface in the ip option. For example, to use DHCP on a NIC that is named eno1, set ip=eno1:dhcp.

     3

     Specify the location of the initramfs file that you uploaded to your TFTP server.

2. Use the PXE or iPXE infrastructure to create the required compute machines for your cluster.

Procedure

1. Confirm that the cluster recognizes the machines:

   $ oc get nodes

   Example output

   NAME      STATUS    ROLES   AGE  VERSION
   master-0  Ready     master  63m  v1.26.0
   master-1  Ready     master  63m  v1.26.0
   master-2  Ready     master  64m  v1.26.0

   The output lists all of the machines that you created.

   Note

   The preceding output might not include the compute nodes, also known as worker nodes, until some CSRs are approved.

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  v1.26.0
   master-1  Ready     master  73m  v1.26.0
   master-2  Ready     master  74m  v1.26.0
   worker-0  Ready     worker  11m  v1.26.0
   worker-1  Ready     worker  11m  v1.26.0

   Note

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

1. Cordon. The MCO marks the node as not schedulable for additional workloads.
2. Drain. The MCO terminates all running workloads on the node, causing the workloads to be rescheduled onto other nodes.
3. Apply. The MCO writes the new configuration to the nodes as needed.
4. Reboot. The MCO restarts the node.
5. Uncordon. The MCO marks the node as schedulable for workloads.

Procedure

1. To see the number of MCO-managed nodes available on your cluster for each machine config pool (MCP), run the following command:

   $ oc get machineconfigpool

   Example output

   NAME      CONFIG                    UPDATED  UPDATING   DEGRADED  MACHINECOUNT  READYMACHINECOUNT  UPDATEDMACHINECOUNT DEGRADEDMACHINECOUNT  AGE
   master    rendered-master-06c9c4…   True     False      False     3             3                  3                   0                     4h42m
   worker    rendered-worker-f4b64…    False    True       False     3             2                  2                   0                     4h42m

   where:

   UPDATED

   The True status indicates that the MCO has applied the current machine config to the nodes in that MCP. The current machine config is specified in the STATUS field in the oc get mcp output. The False status indicates a node in the MCP is updating.

   UPDATING

   The True status indicates that the MCO is applying the desired machine config, as specified in the MachineConfigPool custom resource, to at least one of the nodes in that MCP. The desired machine config is the new, edited machine config. Nodes that are updating might not be available for scheduling. The False status indicates that all nodes in the MCP are updated.

   DEGRADED

   A True status indicates the MCO is blocked from applying the current or desired machine config to at least one of the nodes in that MCP, or the configuration is failing. Nodes that are degraded might not be available for scheduling. A False status indicates that all nodes in the MCP are ready.

   MACHINECOUNT

   Indicates the total number of machines in that MCP.

   READYMACHINECOUNT

   Indicates the total number of machines in that MCP that are ready for scheduling.

   UPDATEDMACHINECOUNT

   Indicates the total number of machines in that MCP that have the current machine config.

   DEGRADEDMACHINECOUNT

   Indicates the total number of machines in that MCP that are marked as degraded or unreconcilable.

   In the previous output, there are three control plane (master) nodes and three worker nodes. The control plane MCP and the associated nodes are updated to the current machine config. The nodes in the worker MCP are being updated to the desired machine config. Two of the nodes in the worker MCP are updated and one is still updating, as indicated by the UPDATEDMACHINECOUNT being 2. There are no issues, as indicated by the DEGRADEDMACHINECOUNT being 0 and DEGRADED being False.

   While the nodes in the MCP are updating, the machine config listed under CONFIG is the current machine config, which the MCP is being updated from. When the update is complete, the listed machine config is the desired machine config, which the MCP was updated to.

   Note

   If a node is being cordoned, that node is not included in the READYMACHINECOUNT, but is included in the MACHINECOUNT. Also, the MCP status is set to UPDATING. Because the node has the current machine config, it is counted in the UPDATEDMACHINECOUNT total:

   Example output

   NAME      CONFIG                    UPDATED  UPDATING   DEGRADED  MACHINECOUNT  READYMACHINECOUNT  UPDATEDMACHINECOUNT DEGRADEDMACHINECOUNT  AGE
   master    rendered-master-06c9c4…   True     False      False     3             3                  3                   0                     4h42m
   worker    rendered-worker-c1b41a…   False    True       False     3             2                  3                   0                     4h42m

2. To check the status of the nodes in an MCP by examining the MachineConfigPool custom resource, run the following command: :

   $ oc describe mcp worker

   Example output

   ...
     Degraded Machine Count:     0
     Machine Count:              3
     Observed Generation:        2
     Ready Machine Count:        3
     Unavailable Machine Count:  0
     Updated Machine Count:      3
   Events:                       <none>

   Note

   If a node is being cordoned, the node is not included in the Ready Machine Count. It is included in the Unavailable Machine Count:

   Example output

   ...
     Degraded Machine Count:     0
     Machine Count:              3
     Observed Generation:        2
     Ready Machine Count:        2
     Unavailable Machine Count:  1
     Updated Machine Count:      3

3. To see each existing MachineConfig object, run the following command:

   $ oc get machineconfigs

   Example output

   NAME                             GENERATEDBYCONTROLLER          IGNITIONVERSION  AGE
   00-master                        2c9371fbb673b97a6fe8b1c52...   3.2.0            5h18m
   00-worker                        2c9371fbb673b97a6fe8b1c52...   3.2.0            5h18m
   01-master-container-runtime      2c9371fbb673b97a6fe8b1c52...   3.2.0            5h18m
   01-master-kubelet                2c9371fbb673b97a6fe8b1c52…     3.2.0            5h18m
   ...
   rendered-master-dde...           2c9371fbb673b97a6fe8b1c52...   3.2.0            5h18m
   rendered-worker-fde...           2c9371fbb673b97a6fe8b1c52...   3.2.0            5h18m

   Note that the MachineConfig objects listed as rendered are not meant to be changed or deleted.

4. To view the contents of a particular machine config (in this case, 01-master-kubelet), run the following command:

   $ oc describe machineconfigs 01-master-kubelet

   The output from the command shows that this MachineConfig object contains both configuration files (cloud.conf and kubelet.conf) and a systemd service (Kubernetes Kubelet):

   Example output

   Name:         01-master-kubelet
   ...
   Spec:
     Config:
       Ignition:
         Version:  3.2.0
       Storage:
         Files:
           Contents:
             Source:   data:,
           Mode:       420
           Overwrite:  true
           Path:       /etc/kubernetes/cloud.conf
           Contents:
             Source:   data:,kind%3A%20KubeletConfiguration%0AapiVersion%3A%20kubelet.config.k8s.io%2Fv1beta1%0Aauthentication%3A%0A%20%20x509%3A%0A%20%20%20%20clientCAFile%3A%20%2Fetc%2Fkubernetes%2Fkubelet-ca.crt%0A%20%20anonymous...
           Mode:       420
           Overwrite:  true
           Path:       /etc/kubernetes/kubelet.conf
       Systemd:
         Units:
           Contents:  [Unit]
   Description=Kubernetes Kubelet
   Wants=rpc-statd.service network-online.target crio.service
   After=network-online.target crio.service
   
   ExecStart=/usr/bin/hyperkube \
       kubelet \
         --config=/etc/kubernetes/kubelet.conf \ ...

Procedure

1. Create a Butane config including the contents of the chrony.conf file. For example, to configure chrony on worker nodes, create a 99-worker-chrony.bu file.

   Note

   See "Creating machine configs with Butane" for information about Butane.

   variant: openshift
   version: 4.13.0
   metadata:
     name: 99-worker-chrony 1
     labels:
       machineconfiguration.openshift.io/role: worker 2
   storage:
     files:
     - path: /etc/chrony.conf
       mode: 0644 3
       overwrite: true
       contents:
         inline: |
           pool 0.rhel.pool.ntp.org iburst 4
           driftfile /var/lib/chrony/drift
           makestep 1.0 3
           rtcsync
           logdir /var/log/chrony

   1 2

   On control plane nodes, substitute master for worker in both of these locations.

   3

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

   4

   Specify any valid, reachable time source, such as the one provided by your DHCP server. Alternately, you can specify any of the following NTP servers: 1.rhel.pool.ntp.org, 2.rhel.pool.ntp.org, or 3.rhel.pool.ntp.org.

2. Use Butane to generate a MachineConfig object file, 99-worker-chrony.yaml, containing the configuration to be delivered to the nodes:

   $ butane 99-worker-chrony.bu -o 99-worker-chrony.yaml

3. Apply the configurations in one of two ways:

   • If the cluster is not running yet, after you generate manifest files, add the MachineConfig object file to the <installation_directory>/openshift directory, and then continue to create the cluster.

   • If the cluster is already running, apply the file:

     $ oc apply -f ./99-worker-chrony.yaml

Procedure

1. Create the MachineConfig CR that disables chronyd for the specified node role.

   1. Save the following YAML in the disable-chronyd.yaml file:

      apiVersion: machineconfiguration.openshift.io/v1
      kind: MachineConfig
      metadata:
        labels:
          machineconfiguration.openshift.io/role: <node_role> 1
        name: disable-chronyd
      spec:
        config:
          ignition:
            version: 3.2.0
          systemd:
            units:
              - contents: |
                  [Unit]
                  Description=NTP client/server
                  Documentation=man:chronyd(8) man:chrony.conf(5)
                  After=ntpdate.service sntp.service ntpd.service
                  Conflicts=ntpd.service systemd-timesyncd.service
                  ConditionCapability=CAP_SYS_TIME
                  [Service]
                  Type=forking
                  PIDFile=/run/chrony/chronyd.pid
                  EnvironmentFile=-/etc/sysconfig/chronyd
                  ExecStart=/usr/sbin/chronyd $OPTIONS
                  ExecStartPost=/usr/libexec/chrony-helper update-daemon
                  PrivateTmp=yes
                  ProtectHome=yes
                  ProtectSystem=full
                  [Install]
                  WantedBy=multi-user.target
                enabled: false
                name: "chronyd.service"

      1

      Node role where you want to disable chronyd, for example, master.

   2. Create the MachineConfig CR by running the following command:

      $ oc create -f disable-chronyd.yaml

Procedure

1. List existing MachineConfig objects for your OpenShift Container Platform cluster to determine how to label your machine config:

   $ oc get MachineConfig

   Example output

   NAME                                               GENERATEDBYCONTROLLER                      IGNITIONVERSION   AGE
   00-master                                          52dd3ba6a9a527fc3ab42afac8d12b693534c8c9   3.2.0             33m
   00-worker                                          52dd3ba6a9a527fc3ab42afac8d12b693534c8c9   3.2.0             33m
   01-master-container-runtime                        52dd3ba6a9a527fc3ab42afac8d12b693534c8c9   3.2.0             33m
   01-master-kubelet                                  52dd3ba6a9a527fc3ab42afac8d12b693534c8c9   3.2.0             33m
   01-worker-container-runtime                        52dd3ba6a9a527fc3ab42afac8d12b693534c8c9   3.2.0             33m
   01-worker-kubelet                                  52dd3ba6a9a527fc3ab42afac8d12b693534c8c9   3.2.0             33m
   99-master-generated-registries                     52dd3ba6a9a527fc3ab42afac8d12b693534c8c9   3.2.0             33m
   99-master-ssh                                                                                 3.2.0             40m
   99-worker-generated-registries                     52dd3ba6a9a527fc3ab42afac8d12b693534c8c9   3.2.0             33m
   99-worker-ssh                                                                                 3.2.0             40m
   rendered-master-23e785de7587df95a4b517e0647e5ab7   52dd3ba6a9a527fc3ab42afac8d12b693534c8c9   3.2.0             33m
   rendered-worker-5d596d9293ca3ea80c896a1191735bb1   52dd3ba6a9a527fc3ab42afac8d12b693534c8c9   3.2.0             33m

2. Create a MachineConfig object file that identifies the kernel argument (for example, 05-worker-kernelarg-selinuxpermissive.yaml)

   apiVersion: machineconfiguration.openshift.io/v1
   kind: MachineConfig
   metadata:
     labels:
       machineconfiguration.openshift.io/role: worker1
     name: 05-worker-kernelarg-selinuxpermissive2
   spec:
     kernelArguments:
       - enforcing=03

   1

   Applies the new kernel argument only to worker nodes.

   2

   Named to identify where it fits among the machine configs (05) and what it does (adds a kernel argument to configure SELinux permissive mode).

   3

   Identifies the exact kernel argument as enforcing=0.

3. Create the new machine config:

   $ oc create -f 05-worker-kernelarg-selinuxpermissive.yaml

4. Check the machine configs to see that the new one was added:

   $ oc get MachineConfig

   Example output

   NAME                                               GENERATEDBYCONTROLLER                      IGNITIONVERSION   AGE
   00-master                                          52dd3ba6a9a527fc3ab42afac8d12b693534c8c9   3.2.0             33m
   00-worker                                          52dd3ba6a9a527fc3ab42afac8d12b693534c8c9   3.2.0             33m
   01-master-container-runtime                        52dd3ba6a9a527fc3ab42afac8d12b693534c8c9   3.2.0             33m
   01-master-kubelet                                  52dd3ba6a9a527fc3ab42afac8d12b693534c8c9   3.2.0             33m
   01-worker-container-runtime                        52dd3ba6a9a527fc3ab42afac8d12b693534c8c9   3.2.0             33m
   01-worker-kubelet                                  52dd3ba6a9a527fc3ab42afac8d12b693534c8c9   3.2.0             33m
   05-worker-kernelarg-selinuxpermissive                                                         3.2.0             105s
   99-master-generated-registries                     52dd3ba6a9a527fc3ab42afac8d12b693534c8c9   3.2.0             33m
   99-master-ssh                                                                                 3.2.0             40m
   99-worker-generated-registries                     52dd3ba6a9a527fc3ab42afac8d12b693534c8c9   3.2.0             33m
   99-worker-ssh                                                                                 3.2.0             40m
   rendered-master-23e785de7587df95a4b517e0647e5ab7   52dd3ba6a9a527fc3ab42afac8d12b693534c8c9   3.2.0             33m
   rendered-worker-5d596d9293ca3ea80c896a1191735bb1   52dd3ba6a9a527fc3ab42afac8d12b693534c8c9   3.2.0             33m

5. Check the nodes:

   $ oc get nodes

   Example output

   NAME                           STATUS                     ROLES    AGE   VERSION
   ip-10-0-136-161.ec2.internal   Ready                      worker   28m   v1.26.0
   ip-10-0-136-243.ec2.internal   Ready                      master   34m   v1.26.0
   ip-10-0-141-105.ec2.internal   Ready,SchedulingDisabled   worker   28m   v1.26.0
   ip-10-0-142-249.ec2.internal   Ready                      master   34m   v1.26.0
   ip-10-0-153-11.ec2.internal    Ready                      worker   28m   v1.26.0
   ip-10-0-153-150.ec2.internal   Ready                      master   34m   v1.26.0

   You can see that scheduling on each worker node is disabled as the change is being applied.

6. Check that the kernel argument worked by going to one of the worker nodes and listing the kernel command line arguments (in /proc/cmdline on the host):

   $ oc debug node/ip-10-0-141-105.ec2.internal

   Example output

   Starting pod/ip-10-0-141-105ec2internal-debug ...
   To use host binaries, run `chroot /host`
   
   sh-4.2# cat /host/proc/cmdline
   BOOT_IMAGE=/ostree/rhcos-... console=tty0 console=ttyS0,115200n8
   rootflags=defaults,prjquota rw root=UUID=fd0... ostree=/ostree/boot.0/rhcos/16...
   coreos.oem.id=qemu coreos.oem.id=ec2 ignition.platform.id=ec2 enforcing=0
   
   sh-4.2# exit

   You should see the enforcing=0 argument added to the other kernel arguments.

Procedure

1. To enable multipathing postinstallation on control plane nodes:

   • Create a machine config file, such as 99-master-kargs-mpath.yaml, that instructs the cluster to add the master label and that identifies the multipath kernel argument, for example:

     apiVersion: machineconfiguration.openshift.io/v1
     kind: MachineConfig
     metadata:
       labels:
         machineconfiguration.openshift.io/role: "master"
       name: 99-master-kargs-mpath
     spec:
       kernelArguments:
         - 'rd.multipath=default'
         - 'root=/dev/disk/by-label/dm-mpath-root'

2. To enable multipathing postinstallation on worker nodes:

   • Create a machine config file, such as 99-worker-kargs-mpath.yaml, that instructs the cluster to add the worker label and that identifies the multipath kernel argument, for example:

     apiVersion: machineconfiguration.openshift.io/v1
     kind: MachineConfig
     metadata:
       labels:
         machineconfiguration.openshift.io/role: "worker"
       name: 99-worker-kargs-mpath
     spec:
       kernelArguments:
         - 'rd.multipath=default'
         - 'root=/dev/disk/by-label/dm-mpath-root'

3. Create the new machine config by using either the master or worker YAML file you previously created:

   $ oc create -f ./99-worker-kargs-mpath.yaml

4. Check the machine configs to see that the new one was added:

   $ oc get MachineConfig

   Example output

   NAME                                               GENERATEDBYCONTROLLER                      IGNITIONVERSION   AGE
   00-master                                          52dd3ba6a9a527fc3ab42afac8d12b693534c8c9   3.2.0             33m
   00-worker                                          52dd3ba6a9a527fc3ab42afac8d12b693534c8c9   3.2.0             33m
   01-master-container-runtime                        52dd3ba6a9a527fc3ab42afac8d12b693534c8c9   3.2.0             33m
   01-master-kubelet                                  52dd3ba6a9a527fc3ab42afac8d12b693534c8c9   3.2.0             33m
   01-worker-container-runtime                        52dd3ba6a9a527fc3ab42afac8d12b693534c8c9   3.2.0             33m
   01-worker-kubelet                                  52dd3ba6a9a527fc3ab42afac8d12b693534c8c9   3.2.0             33m
   99-master-generated-registries                     52dd3ba6a9a527fc3ab42afac8d12b693534c8c9   3.2.0             33m
   99-master-ssh                                                                                 3.2.0             40m
   99-worker-generated-registries                     52dd3ba6a9a527fc3ab42afac8d12b693534c8c9   3.2.0             33m
   99-worker-kargs-mpath                              52dd3ba6a9a527fc3ab42afac8d12b693534c8c9   3.2.0             105s
   99-worker-ssh                                                                                 3.2.0             40m
   rendered-master-23e785de7587df95a4b517e0647e5ab7   52dd3ba6a9a527fc3ab42afac8d12b693534c8c9   3.2.0             33m
   rendered-worker-5d596d9293ca3ea80c896a1191735bb1   52dd3ba6a9a527fc3ab42afac8d12b693534c8c9   3.2.0             33m

5. Check the nodes:

   $ oc get nodes

   Example output

   NAME                           STATUS                     ROLES    AGE   VERSION
   ip-10-0-136-161.ec2.internal   Ready                      worker   28m   v1.26.0
   ip-10-0-136-243.ec2.internal   Ready                      master   34m   v1.26.0
   ip-10-0-141-105.ec2.internal   Ready,SchedulingDisabled   worker   28m   v1.26.0
   ip-10-0-142-249.ec2.internal   Ready                      master   34m   v1.26.0
   ip-10-0-153-11.ec2.internal    Ready                      worker   28m   v1.26.0
   ip-10-0-153-150.ec2.internal   Ready                      master   34m   v1.26.0

   You can see that scheduling on each worker node is disabled as the change is being applied.

6. Check that the kernel argument worked by going to one of the worker nodes and listing the kernel command line arguments (in /proc/cmdline on the host):

   $ oc debug node/ip-10-0-141-105.ec2.internal

   Example output

   Starting pod/ip-10-0-141-105ec2internal-debug ...
   To use host binaries, run `chroot /host`
   
   sh-4.2# cat /host/proc/cmdline
   ...
   rd.multipath=default root=/dev/disk/by-label/dm-mpath-root
   ...
   
   sh-4.2# exit

   You should see the added kernel arguments.

Procedure

1. Create a machine config for the real-time kernel: Create a YAML file (for example, 99-worker-realtime.yaml) that contains a MachineConfig object for the realtime kernel type. This example tells the cluster to use a real-time kernel for all worker nodes:

   $ cat << EOF > 99-worker-realtime.yaml
   apiVersion: machineconfiguration.openshift.io/v1
   kind: MachineConfig
   metadata:
     labels:
       machineconfiguration.openshift.io/role: "worker"
     name: 99-worker-realtime
   spec:
     kernelType: realtime
   EOF

2. Add the machine config to the cluster. Type the following to add the machine config to the cluster:

   $ oc create -f 99-worker-realtime.yaml

3. Check the real-time kernel: Once each impacted node reboots, log in to the cluster and run the following commands to make sure that the real-time kernel has replaced the regular kernel for the set of nodes you configured:

   $ oc get nodes

   Example output

   NAME                                        STATUS  ROLES    AGE   VERSION
   ip-10-0-143-147.us-east-2.compute.internal  Ready   worker   103m  v1.26.0
   ip-10-0-146-92.us-east-2.compute.internal   Ready   worker   101m  v1.26.0
   ip-10-0-169-2.us-east-2.compute.internal    Ready   worker   102m  v1.26.0

   $ oc debug node/ip-10-0-143-147.us-east-2.compute.internal

   Example output

   Starting pod/ip-10-0-143-147us-east-2computeinternal-debug ...
   To use host binaries, run `chroot /host`
   
   sh-4.4# uname -a
   Linux <worker_node> 4.18.0-147.3.1.rt24.96.el8_1.x86_64 #1 SMP PREEMPT RT
           Wed Nov 27 18:29:55 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux

   The kernel name contains rt and text “PREEMPT RT” indicates that this is a real-time kernel.

4. To go back to the regular kernel, delete the MachineConfig object:

   $ oc delete -f 99-worker-realtime.yaml

Procedure

1. Create a Butane config file, 40-worker-custom-journald.bu, that includes an /etc/systemd/journald.conf file with the required settings.

   Note

   See "Creating machine configs with Butane" for information about Butane.

   variant: openshift
   version: 4.13.0
   metadata:
     name: 40-worker-custom-journald
     labels:
       machineconfiguration.openshift.io/role: worker
   storage:
     files:
     - path: /etc/systemd/journald.conf
       mode: 0644
       overwrite: true
       contents:
         inline: |
           # Disable rate limiting
           RateLimitInterval=1s
           RateLimitBurst=10000
           Storage=volatile
           Compress=no
           MaxRetentionSec=30s

2. Use Butane to generate a MachineConfig object file, 40-worker-custom-journald.yaml, containing the configuration to be delivered to the worker nodes:

   $ butane 40-worker-custom-journald.bu -o 40-worker-custom-journald.yaml

3. Apply the machine config to the pool:

   $ oc apply -f 40-worker-custom-journald.yaml

4. Check that the new machine config is applied and that the nodes are not in a degraded state. It might take a few minutes. The worker pool will show the updates in progress, as each node successfully has the new machine config applied:

   $ oc get machineconfigpool
   NAME   CONFIG             UPDATED UPDATING DEGRADED MACHINECOUNT READYMACHINECOUNT UPDATEDMACHINECOUNT DEGRADEDMACHINECOUNT AGE
   master rendered-master-35 True    False    False    3            3                 3                   0                    34m
   worker rendered-worker-d8 False   True     False    3            1                 1                   0                    34m

5. To check that the change was applied, you can log in to a worker node:

   $ oc get node | grep worker
   ip-10-0-0-1.us-east-2.compute.internal   Ready    worker   39m   v0.0.0-master+$Format:%h$
   $ oc debug node/ip-10-0-0-1.us-east-2.compute.internal
   Starting pod/ip-10-0-141-142us-east-2computeinternal-debug ...
   ...
   sh-4.2# chroot /host
   sh-4.4# cat /etc/systemd/journald.conf
   # Disable rate limiting
   RateLimitInterval=1s
   RateLimitBurst=10000
   Storage=volatile
   Compress=no
   MaxRetentionSec=30s
   sh-4.4# exit

Procedure

1. Create a machine config for extensions: Create a YAML file (for example, 80-extensions.yaml) that contains a MachineConfig extensions object. This example tells the cluster to add the usbguard extension.

   $ cat << EOF > 80-extensions.yaml
   apiVersion: machineconfiguration.openshift.io/v1
   kind: MachineConfig
   metadata:
     labels:
       machineconfiguration.openshift.io/role: worker
     name: 80-worker-extensions
   spec:
     config:
       ignition:
         version: 3.2.0
     extensions:
       - usbguard
   EOF

2. Add the machine config to the cluster. Type the following to add the machine config to the cluster:

   $ oc create -f 80-extensions.yaml

   This sets all worker nodes to have rpm packages for usbguard installed.

3. Check that the extensions were applied:

   $ oc get machineconfig 80-worker-extensions

   Example output

   NAME                 GENERATEDBYCONTROLLER IGNITIONVERSION AGE
   80-worker-extensions                       3.2.0           57s

4. Check that the new machine config is now applied and that the nodes are not in a degraded state. It may take a few minutes. The worker pool will show the updates in progress, as each machine successfully has the new machine config applied:

   $ oc get machineconfigpool

   Example output

   NAME   CONFIG             UPDATED UPDATING DEGRADED MACHINECOUNT READYMACHINECOUNT UPDATEDMACHINECOUNT DEGRADEDMACHINECOUNT AGE
   master rendered-master-35 True    False    False    3            3                 3                   0                    34m
   worker rendered-worker-d8 False   True     False    3            1                 1                   0                    34m

5. Check the extensions. To check that the extension was applied, run:

   $ oc get node | grep worker

   Example output

   NAME                                        STATUS  ROLES    AGE   VERSION
   ip-10-0-169-2.us-east-2.compute.internal    Ready   worker   102m  v1.26.0

   $ oc debug node/ip-10-0-169-2.us-east-2.compute.internal

   Example output

   ...
   To use host binaries, run `chroot /host`
   sh-4.4# chroot /host
   sh-4.4# rpm -q usbguard
   usbguard-0.7.4-4.el8.x86_64.rpm

Procedure

1. Create a Butane config file, 98-worker-firmware-blob.bu, that updates the search path so that it is root-owned and writable to local storage. The following example places the custom blob file from your local workstation onto nodes under /var/lib/firmware.

   Note

   See "Creating machine configs with Butane" for information about Butane.

   Butane config file for custom firmware blob

   variant: openshift
   version: 4.13.0
   metadata:
     labels:
       machineconfiguration.openshift.io/role: worker
     name: 98-worker-firmware-blob
   storage:
     files:
     - path: /var/lib/firmware/<package_name> 1
       contents:
         local: <package_name> 2
       mode: 0644 3
   openshift:
     kernel_arguments:
       - 'firmware_class.path=/var/lib/firmware' 4

   1

   Sets the path on the node where the firmware package is copied to.

   2

   Specifies a file with contents that are read from a local file directory on the system running Butane. The path of the local file is relative to a files-dir directory, which must be specified by using the --files-dir option with Butane in the following step.

   3

   Sets the permissions for the file on the RHCOS node. It is recommended to set 0644 permissions.

   4

   The firmware_class.path parameter customizes the kernel search path of where to look for the custom firmware blob that was copied from your local workstation onto the root file system of the node. This example uses /var/lib/firmware as the customized path.

2. Run Butane to generate a MachineConfig object file that uses a copy of the firmware blob on your local workstation named 98-worker-firmware-blob.yaml. The firmware blob contains the configuration to be delivered to the nodes. The following example uses the --files-dir option to specify the directory on your workstation where the local file or files are located:

   $ butane 98-worker-firmware-blob.bu -o 98-worker-firmware-blob.yaml --files-dir <directory_including_package_name>

3. Apply the configurations to the nodes in one of two ways:

   • If the cluster is not running yet, after you generate manifest files, add the MachineConfig object file to the <installation_directory>/openshift directory, and then continue to create the cluster.

   • If the cluster is already running, apply the file:

     $ oc apply -f 98-worker-firmware-blob.yaml

     A MachineConfig object YAML file is created for you to finish configuring your machines.

4. Save the Butane config in case you need to update the MachineConfig object in the future.

Prerequisites

1. Obtain the label associated with the static MachineConfigPool CR for the type of node you want to configure. Perform one of the following steps:

   1. View the machine config pool:

      $ oc describe machineconfigpool <name>

      For example:

      $ oc describe machineconfigpool worker

      Example output

      apiVersion: machineconfiguration.openshift.io/v1
      kind: MachineConfigPool
      metadata:
        creationTimestamp: 2019-02-08T14:52:39Z
        generation: 1
        labels:
          custom-kubelet: set-max-pods 1

      1

      If a label has been added it appears under labels.

   2. If the label is not present, add a key/value pair:

      $ oc label machineconfigpool worker custom-kubelet=set-max-pods

Procedure

1. View the available machine configuration objects that you can select:

   $ oc get machineconfig

   By default, the two kubelet-related configs are 01-master-kubelet and 01-worker-kubelet.

2. Check the current value for the maximum pods per node:

   $ oc describe node <node_name>

   For example:

   $ oc describe node ci-ln-5grqprb-f76d1-ncnqq-worker-a-mdv94

   Look for value: pods: <value> in the Allocatable stanza:

   Example output

   Allocatable:
    attachable-volumes-aws-ebs:  25
    cpu:                         3500m
    hugepages-1Gi:               0
    hugepages-2Mi:               0
    memory:                      15341844Ki
    pods:                        250

3. Set the maximum pods per node on the worker nodes by creating a custom resource file that contains the kubelet configuration:

   Important

   Kubelet configurations that target a specific machine config pool also affect any dependent pools. For example, creating a kubelet configuration for the pool containing worker nodes will also apply to any subset pools, including the pool containing infrastructure nodes. To avoid this, you must create a new machine config pool with a selection expression that only includes worker nodes, and have your kubelet configuration target this new pool.

   apiVersion: machineconfiguration.openshift.io/v1
   kind: KubeletConfig
   metadata:
     name: set-max-pods
   spec:
     machineConfigPoolSelector:
       matchLabels:
         custom-kubelet: set-max-pods 1
     kubeletConfig:
       maxPods: 500 2

   1

   Enter the label from the machine config pool.

   2

   Add the kubelet configuration. In this example, use maxPods to set the maximum pods per node.

   Note

   The rate at which the kubelet talks to the API server depends on queries per second (QPS) and burst values. The default values, 50 for kubeAPIQPS and 100 for kubeAPIBurst, are sufficient if there are limited pods running on each node. It is recommended to update the kubelet QPS and burst rates if there are enough CPU and memory resources on the node.

   apiVersion: machineconfiguration.openshift.io/v1
   kind: KubeletConfig
   metadata:
     name: set-max-pods
   spec:
     machineConfigPoolSelector:
       matchLabels:
         custom-kubelet: set-max-pods
     kubeletConfig:
       maxPods: <pod_count>
       kubeAPIBurst: <burst_rate>
       kubeAPIQPS: <QPS>

   1. Update the machine config pool for workers with the label:

      $ oc label machineconfigpool worker custom-kubelet=set-max-pods

   2. Create the KubeletConfig object:

      $ oc create -f change-maxPods-cr.yaml

   3. Verify that the KubeletConfig object is created:

      $ oc get kubeletconfig

      Example output

      NAME                AGE
      set-max-pods        15m

      Depending on the number of worker nodes in the cluster, wait for the worker nodes to be rebooted one by one. For a cluster with 3 worker nodes, this could take about 10 to 15 minutes.

4. Verify that the changes are applied to the node:

   1. Check on a worker node that the maxPods value changed:

      $ oc describe node <node_name>

   2. Locate the Allocatable stanza:

       ...
      Allocatable:
        attachable-volumes-gce-pd:  127
        cpu:                        3500m
        ephemeral-storage:          123201474766
        hugepages-1Gi:              0
        hugepages-2Mi:              0
        memory:                     14225400Ki
        pods:                       500 1
       ...

      1

      In this example, the pods parameter should report the value you set in the KubeletConfig object.

5. Verify the change in the KubeletConfig object:

   $ oc get kubeletconfigs set-max-pods -o yaml

   This should show a status of True and type:Success, as shown in the following example:

   spec:
     kubeletConfig:
       maxPods: 500
     machineConfigPoolSelector:
       matchLabels:
         custom-kubelet: set-max-pods
   status:
     conditions:
     - lastTransitionTime: "2021-06-30T17:04:07Z"
       message: Success
       status: "True"
       type: Success

1. Create a YAML file for the ContainerRuntimeConfig CR:

   apiVersion: machineconfiguration.openshift.io/v1
   kind: ContainerRuntimeConfig
   metadata:
    name: overlay-size
   spec:
    machineConfigPoolSelector:
      matchLabels:
        pools.operator.machineconfiguration.openshift.io/worker: '' 1
    containerRuntimeConfig: 2
      logLevel: debug
      overlaySize: 8G

   1

   Specify a label for the machine config pool that you want you want to modify.

   2

   Set the parameters as needed.

2. Create the ContainerRuntimeConfig CR:

   $ oc create -f <file_name>.yaml

3. Verify that the CR is created:

   $ oc get ContainerRuntimeConfig

   Example output

   NAME           AGE
   overlay-size   3m19s

4. Check that a new containerruntime machine config is created:

   $ oc get machineconfigs | grep containerrun

   Example output

   99-worker-generated-containerruntime   2c9371fbb673b97a6fe8b1c52691999ed3a1bfc2  3.2.0  31s

5. Monitor the machine config pool until all are shown as ready:

   $ oc get mcp worker

   Example output

   NAME    CONFIG               UPDATED  UPDATING  DEGRADED  MACHINECOUNT  READYMACHINECOUNT  UPDATEDMACHINECOUNT  DEGRADEDMACHINECOUNT  AGE
   worker  rendered-worker-169  False    True      False     3             1                  1                    0                     9h

6. Verify that the settings were applied in CRI-O:

   1. Open an oc debug session to a node in the machine config pool and run chroot /host.

      $ oc debug node/<node_name>

      sh-4.4# chroot /host

   2. Verify the changes in the crio.conf file:

      sh-4.4# crio config | grep 'log_level'

      Example output

      log_level = "debug"

   3. Verify the changes in the `storage.conf`file:

      sh-4.4# head -n 7 /etc/containers/storage.conf

      Example output

      [storage]
        driver = "overlay"
        runroot = "/var/run/containers/storage"
        graphroot = "/var/lib/containers/storage"
        [storage.options]
          additionalimagestores = []
          size = "8G"

Procedure

1. Create the configuration object:

   $ oc apply -f overlaysize.yml

2. To apply the new CRI-O configuration to your worker nodes, edit the worker machine config pool:

   $ oc edit machineconfigpool worker

3. Add the custom-crio label based on the matchLabels name you set in the ContainerRuntimeConfig CRD:

   apiVersion: machineconfiguration.openshift.io/v1
   kind: MachineConfigPool
   metadata:
     creationTimestamp: "2020-07-09T15:46:34Z"
     generation: 3
     labels:
       custom-crio: overlay-size
       machineconfiguration.openshift.io/mco-built-in: ""

4. Save the changes, then view the machine configs:

   $ oc get machineconfigs

   New 99-worker-generated-containerruntime and rendered-worker-xyz objects are created:

   Example output

   99-worker-generated-containerruntime  4173030d89fbf4a7a0976d1665491a4d9a6e54f1   3.2.0             7m42s
   rendered-worker-xyz                   4173030d89fbf4a7a0976d1665491a4d9a6e54f1   3.2.0             7m36s

5. After those objects are created, monitor the machine config pool for the changes to be applied:

   $ oc get mcp worker

   The worker nodes show UPDATING as True, as well as the number of machines, the number updated, and other details:

   Example output

   NAME   CONFIG              UPDATED   UPDATING   DEGRADED  MACHINECOUNT  READYMACHINECOUNT  UPDATEDMACHINECOUNT   DEGRADEDMACHINECOUNT   AGE
   worker rendered-worker-xyz False True False     3             2                   2                    0                      20h

   When complete, the worker nodes transition back to UPDATING as False, and the UPDATEDMACHINECOUNT number matches the MACHINECOUNT:

   Example output

   NAME   CONFIG              UPDATED   UPDATING   DEGRADED  MACHINECOUNT  READYMACHINECOUNT  UPDATEDMACHINECOUNT   DEGRADEDMACHINECOUNT   AGE
   worker   rendered-worker-xyz   True      False      False      3         3            3             0           20h

   Looking at a worker machine, you see that the new 8 GB max size configuration is applied to all of the workers:

   Example output

   head -n 7 /etc/containers/storage.conf
   [storage]
     driver = "overlay"
     runroot = "/var/run/containers/storage"
     graphroot = "/var/lib/containers/storage"
     [storage.options]
       additionalimagestores = []
       size = "8G"

   Looking inside a container, you see that the root partition is now 8 GB:

   Example output

   ~ $ df -h
   Filesystem                Size      Used Available Use% Mounted on
   overlay                   8.0G      8.0K      8.0G   0% /

Procedure

1. View the compute machine sets that are in the cluster by running the following command:

   $ oc get machinesets -n openshift-machine-api

   The compute machine sets are listed in the form of <clusterid>-worker-<aws-region-az>.

2. View the compute machines that are in the cluster by running the following command:

   $ oc get machine -n openshift-machine-api

3. Set the annotation on the compute machine that you want to delete by running the following command:

   $ oc annotate machine/<machine_name> -n openshift-machine-api machine.openshift.io/delete-machine="true"

4. Scale the compute machine set by running one of the following commands:

   $ oc scale --replicas=2 machineset <machineset> -n openshift-machine-api

   Or:

   $ oc edit machineset <machineset> -n openshift-machine-api

   Tip

   You can alternatively apply the following YAML to scale the compute machine set:

   apiVersion: machine.openshift.io/v1beta1
   kind: MachineSet
   metadata:
     name: <machineset>
     namespace: openshift-machine-api
   spec:
     replicas: 2

   You can scale the compute machine set up or down. It takes several minutes for the new machines to be available.

   Important

   By default, the machine controller tries to drain the node that is backed by the machine until it succeeds. In some situations, such as with a misconfigured pod disruption budget, the drain operation might not be able to succeed. If the drain operation fails, the machine controller cannot proceed removing the machine.

   You can skip draining the node by annotating machine.openshift.io/exclude-node-draining in a specific machine.

1. Edit the Scheduler Operator CR to add the default cluster-wide node selectors:

   $ oc edit scheduler cluster

   Example Scheduler Operator CR with a node selector

   apiVersion: config.openshift.io/v1
   kind: Scheduler
   metadata:
     name: cluster
   ...
   spec:
     defaultNodeSelector: type=user-node,region=east 1
     mastersSchedulable: false

   1

   Add a node selector with the appropriate <key>:<value> pairs.

   After making this change, wait for the pods in the openshift-kube-apiserver project to redeploy. This can take several minutes. The default cluster-wide node selector does not take effect until the pods redeploy.

2. Add labels to a node by using a compute machine set or editing the node directly:

   • Use a compute machine set to add labels to nodes managed by the compute machine set when a node is created:

     1. Run the following command to add labels to a MachineSet object:

        $ oc patch MachineSet <name> --type='json' -p='[{"op":"add","path":"/spec/template/spec/metadata/labels", "value":{"<key>"="<value>","<key>"="<value>"}}]'  -n openshift-machine-api 1

        1

        Add a <key>/<value> pair for each label.

        For example:

        $ oc patch MachineSet ci-ln-l8nry52-f76d1-hl7m7-worker-c --type='json' -p='[{"op":"add","path":"/spec/template/spec/metadata/labels", "value":{"type":"user-node","region":"east"}}]'  -n openshift-machine-api

        Tip

        You can alternatively apply the following YAML to add labels to a compute machine set:

        apiVersion: machine.openshift.io/v1beta1
        kind: MachineSet
        metadata:
          name: <machineset>
          namespace: openshift-machine-api
        spec:
          template:
            spec:
              metadata:
                labels:
                  region: "east"
                  type: "user-node"

     2. Verify that the labels are added to the MachineSet object by using the oc edit command:

        For example:

        $ oc edit MachineSet abc612-msrtw-worker-us-east-1c -n openshift-machine-api

        Example MachineSet object

        apiVersion: machine.openshift.io/v1beta1
        kind: MachineSet
          ...
        spec:
          ...
          template:
            metadata:
          ...
            spec:
              metadata:
                labels:
                  region: east
                  type: user-node
          ...

     3. Redeploy the nodes associated with that compute machine set by scaling down to 0 and scaling up the nodes:

        For example:

        $ oc scale --replicas=0 MachineSet ci-ln-l8nry52-f76d1-hl7m7-worker-c -n openshift-machine-api

        $ oc scale --replicas=1 MachineSet ci-ln-l8nry52-f76d1-hl7m7-worker-c -n openshift-machine-api

     4. When the nodes are ready and available, verify that the label is added to the nodes by using the oc get command:

        $ oc get nodes -l <key>=<value>

        For example:

        $ oc get nodes -l type=user-node

        Example output

        NAME                                       STATUS   ROLES    AGE   VERSION
        ci-ln-l8nry52-f76d1-hl7m7-worker-c-vmqzp   Ready    worker   61s   v1.26.0

   • Add labels directly to a node:

     1. Edit the Node object for the node:

        $ oc label nodes <name> <key>=<value>

        For example, to label a node:

        $ oc label nodes ci-ln-l8nry52-f76d1-hl7m7-worker-b-tgq49 type=user-node region=east

        Tip

        You can alternatively apply the following YAML to add labels to a node:

        kind: Node
        apiVersion: v1
        metadata:
          name: <node_name>
          labels:
            type: "user-node"
            region: "east"

     2. Verify that the labels are added to the node using the oc get command:

        $ oc get nodes -l <key>=<value>,<key>=<value>

        For example:

        $ oc get nodes -l type=user-node,region=east

        Example output

        NAME                                       STATUS   ROLES    AGE   VERSION
        ci-ln-l8nry52-f76d1-hl7m7-worker-b-tgq49   Ready    worker   17m   v1.26.0

Procedure

1. Create a deployment resource YAML file for an example application to be deployed in the edge worker node that operates in a Local Zone subnet. Ensure that you specify the correct tolerations that match the taints for the edge worker node.

   Example of a configured deployment resource for an edge worker node that operates in a Local Zone subnet

   kind: Namespace
   apiVersion: v1
   metadata:
     name: <local_zone_application_namespace>
   ---
   kind: PersistentVolumeClaim
   apiVersion: v1
   metadata:
     name: <pvc_name>
     namespace: <local_zone_application_namespace>
   spec:
     accessModes:
       - ReadWriteOnce
     resources:
       requests:
         storage: 10Gi
     storageClassName: gp2-csi 1
     volumeMode: Filesystem
   ---
   apiVersion: apps/v1
   kind: Deployment 2
   metadata:
     name: <local_zone_application> 3
     namespace: <local_zone_application_namespace> 4
   spec:
     selector:
       matchLabels:
         app: <local_zone_application>
     replicas: 1
     template:
       metadata:
         labels:
           app: <local_zone_application>
           zone-group: ${ZONE_GROUP_NAME} 5
       spec:
         securityContext:
           seccompProfile:
             type: RuntimeDefault
         nodeSelector: 6
           machine.openshift.io/zone-group: ${ZONE_GROUP_NAME}
         tolerations: 7
         - key: "node-role.kubernetes.io/edge"
           operator: "Equal"
           value: ""
           effect: "NoSchedule"
         containers:
           - image: openshift/origin-node
             command:
              - "/bin/socat"
             args:
               - TCP4-LISTEN:8080,reuseaddr,fork
               - EXEC:'/bin/bash -c \"printf \\\"HTTP/1.0 200 OK\r\n\r\n\\\"; sed -e \\\"/^\r/q\\\"\"'
             imagePullPolicy: Always
             name: echoserver
             ports:
               - containerPort: 8080
             volumeMounts:
               - mountPath: "/mnt/storage"
                 name: data
         volumes:
         - name: data
           persistentVolumeClaim:
             claimName: <pvc_name>

   1

   storageClassName: For the Local Zone configuration, you must specify gp2-csi.

   2

   kind: Defines the deployment resource.

   3

   name: Specifies the name of your Local Zone application. For example, local-zone-demo-app-nyc-1.

   4

   namespace: Defines the namespace for the AWS Local Zone where you want to run the user workload. For example: local-zone-app-nyc-1a.

   5

   zone-group: Defines the group to where a zone belongs. For example, us-east-1-iah-1.

   6

   nodeSelector: Targets edge worker nodes that match the specified labels.

   7

   tolerations: Sets the values that match with the taints defined on the MachineSet manifest for the Local Zone node.

2. Create a service resource YAML file for the node. This resource exposes a pod from a targeted edge worker node to services that run inside your Local Zone network.

   Example of a configured service resource for an edge worker node that operates in a Local Zone subnet

   apiVersion: v1
   kind: Service 1
   metadata:
     name:  <local_zone_application>
     namespace: <local_zone_application_namespace>
   spec:
     ports:
       - port: 80
         targetPort: 8080
         protocol: TCP
     type: NodePort
     selector: 2
       app: <local_zone_application>

   1

   kind: Defines the service resource.

   2

   selector: Specifies the label type applied to managed pods.

1. Move to the medium worker latency profile:

   1. Edit the node.config object:

      $ oc edit nodes.config/cluster

   2. Add spec.workerLatencyProfile: MediumUpdateAverageReaction:

      Example node.config object

      apiVersion: config.openshift.io/v1
      kind: Node
      metadata:
        annotations:
          include.release.openshift.io/ibm-cloud-managed: "true"
          include.release.openshift.io/self-managed-high-availability: "true"
          include.release.openshift.io/single-node-developer: "true"
          release.openshift.io/create-only: "true"
        creationTimestamp: "2022-07-08T16:02:51Z"
        generation: 1
        name: cluster
        ownerReferences:
        - apiVersion: config.openshift.io/v1
          kind: ClusterVersion
          name: version
          uid: 36282574-bf9f-409e-a6cd-3032939293eb
        resourceVersion: "1865"
        uid: 0c0f7a4c-4307-4187-b591-6155695ac85b
      spec:
        workerLatencyProfile: MediumUpdateAverageReaction 1
      
      # ...

      1

      Specifies the medium worker latency policy.

      Scheduling on each worker node is disabled as the change is being applied.

2. Optional: Move to the low worker latency profile:

   1. Edit the node.config object:

      $ oc edit nodes.config/cluster

   2. Change the spec.workerLatencyProfile value to LowUpdateSlowReaction:

      Example node.config object

      apiVersion: config.openshift.io/v1
      kind: Node
      metadata:
        annotations:
          include.release.openshift.io/ibm-cloud-managed: "true"
          include.release.openshift.io/self-managed-high-availability: "true"
          include.release.openshift.io/single-node-developer: "true"
          release.openshift.io/create-only: "true"
        creationTimestamp: "2022-07-08T16:02:51Z"
        generation: 1
        name: cluster
        ownerReferences:
        - apiVersion: config.openshift.io/v1
          kind: ClusterVersion
          name: version
          uid: 36282574-bf9f-409e-a6cd-3032939293eb
        resourceVersion: "1865"
        uid: 0c0f7a4c-4307-4187-b591-6155695ac85b
      spec:
        workerLatencyProfile: LowUpdateSlowReaction 1
      
      # ...

      1

      Specifies use of the low worker latency policy.

Procedure

1. Create a new YAML file that contains the compute machine set custom resource (CR) sample and is named <file_name>.yaml.

   Ensure that you set the <clusterID> and <role> parameter values.

2. Optional: If you are not sure which value to set for a specific field, you can check an existing compute machine set from your cluster.

   1. To list the compute machine sets in your cluster, run the following command:

      $ oc get machinesets -n openshift-machine-api

      Example output

      NAME                                DESIRED   CURRENT   READY   AVAILABLE   AGE
      agl030519-vplxk-worker-us-east-1a   1         1         1       1           55m
      agl030519-vplxk-worker-us-east-1b   1         1         1       1           55m
      agl030519-vplxk-worker-us-east-1c   1         1         1       1           55m
      agl030519-vplxk-worker-us-east-1d   0         0                             55m
      agl030519-vplxk-worker-us-east-1e   0         0                             55m
      agl030519-vplxk-worker-us-east-1f   0         0                             55m

   2. To view values of a specific compute machine set custom resource (CR), run the following command:

      $ oc get machineset <machineset_name> \
        -n openshift-machine-api -o yaml

      Example output

      apiVersion: machine.openshift.io/v1beta1
      kind: MachineSet
      metadata:
        labels:
          machine.openshift.io/cluster-api-cluster: <infrastructure_id> 1
        name: <infrastructure_id>-<role> 2
        namespace: openshift-machine-api
      spec:
        replicas: 1
        selector:
          matchLabels:
            machine.openshift.io/cluster-api-cluster: <infrastructure_id>
            machine.openshift.io/cluster-api-machineset: <infrastructure_id>-<role>
        template:
          metadata:
            labels:
              machine.openshift.io/cluster-api-cluster: <infrastructure_id>
              machine.openshift.io/cluster-api-machine-role: <role>
              machine.openshift.io/cluster-api-machine-type: <role>
              machine.openshift.io/cluster-api-machineset: <infrastructure_id>-<role>
          spec:
            providerSpec: 3
              ...

      1

      The cluster infrastructure ID.

      2

      A default node label.

      Note

      For clusters that have user-provisioned infrastructure, a compute machine set can only create worker and infra type machines.

      3

      The values in the <providerSpec> section of the compute machine set CR are platform-specific. For more information about <providerSpec> parameters in the CR, see the sample compute machine set CR configuration for your provider.

3. Create a MachineSet CR by running the following command:

   $ oc create -f <file_name>.yaml

Procedure

1. Add a label to the worker node that you want to act as application node:

   $ oc label node <node-name> node-role.kubernetes.io/app=""

2. Add a label to the worker nodes that you want to act as infrastructure nodes:

   $ oc label node <node-name> node-role.kubernetes.io/infra=""

3. Check to see if applicable nodes now have the infra role and app roles:

   $ oc get nodes

4. Create a default cluster-wide node selector. The default node selector is applied to pods created in all namespaces. This creates an intersection with any existing node selectors on a pod, which additionally constrains the pod’s selector.

   Important

   If the default node selector key conflicts with the key of a pod’s label, then the default node selector is not applied.

   However, do not set a default node selector that might cause a pod to become unschedulable. For example, setting the default node selector to a specific node role, such as node-role.kubernetes.io/infra="", when a pod’s label is set to a different node role, such as node-role.kubernetes.io/master="", can cause the pod to become unschedulable. For this reason, use caution when setting the default node selector to specific node roles.

   You can alternatively use a project node selector to avoid cluster-wide node selector key conflicts.

   1. Edit the Scheduler object:

      $ oc edit scheduler cluster

   2. Add the defaultNodeSelector field with the appropriate node selector:

      apiVersion: config.openshift.io/v1
      kind: Scheduler
      metadata:
        name: cluster
      spec:
        defaultNodeSelector: node-role.kubernetes.io/infra="" 1
      # ...

      1

      This example node selector deploys pods on infrastructure nodes by default.

   3. Save the file to apply the changes.

Procedure

1. Add a label to the node you want to assign as the infra node with a specific label:

   $ oc label node <node_name> <label>

   $ oc label node ci-ln-n8mqwr2-f76d1-xscn2-worker-c-6fmtx node-role.kubernetes.io/infra=

2. Create a machine config pool that contains both the worker role and your custom role as machine config selector:

   $ cat infra.mcp.yaml

   Example output

   apiVersion: machineconfiguration.openshift.io/v1
   kind: MachineConfigPool
   metadata:
     name: infra
   spec:
     machineConfigSelector:
       matchExpressions:
         - {key: machineconfiguration.openshift.io/role, operator: In, values: [worker,infra]} 1
     nodeSelector:
       matchLabels:
         node-role.kubernetes.io/infra: "" 2

   1

   Add the worker role and your custom role.

   2

   Add the label you added to the node as a nodeSelector.

   Note

   Custom machine config pools inherit machine configs from the worker pool. Custom pools use any machine config targeted for the worker pool, but add the ability to also deploy changes that are targeted at only the custom pool. Because a custom pool inherits resources from the worker pool, any change to the worker pool also affects the custom pool.

3. After you have the YAML file, you can create the machine config pool:

   $ oc create -f infra.mcp.yaml

4. Check the machine configs to ensure that the infrastructure configuration rendered successfully:

   $ oc get machineconfig

   Example output

   NAME                                                        GENERATEDBYCONTROLLER                      IGNITIONVERSION   CREATED
   00-master                                                   365c1cfd14de5b0e3b85e0fc815b0060f36ab955   3.2.0             31d
   00-worker                                                   365c1cfd14de5b0e3b85e0fc815b0060f36ab955   3.2.0             31d
   01-master-container-runtime                                 365c1cfd14de5b0e3b85e0fc815b0060f36ab955   3.2.0             31d
   01-master-kubelet                                           365c1cfd14de5b0e3b85e0fc815b0060f36ab955   3.2.0             31d
   01-worker-container-runtime                                 365c1cfd14de5b0e3b85e0fc815b0060f36ab955   3.2.0             31d
   01-worker-kubelet                                           365c1cfd14de5b0e3b85e0fc815b0060f36ab955   3.2.0             31d
   99-master-1ae2a1e0-a115-11e9-8f14-005056899d54-registries   365c1cfd14de5b0e3b85e0fc815b0060f36ab955   3.2.0             31d
   99-master-ssh                                                                                          3.2.0             31d
   99-worker-1ae64748-a115-11e9-8f14-005056899d54-registries   365c1cfd14de5b0e3b85e0fc815b0060f36ab955   3.2.0             31d
   99-worker-ssh                                                                                          3.2.0             31d
   rendered-infra-4e48906dca84ee702959c71a53ee80e7             365c1cfd14de5b0e3b85e0fc815b0060f36ab955   3.2.0             23m
   rendered-master-072d4b2da7f88162636902b074e9e28e            5b6fb8349a29735e48446d435962dec4547d3090   3.2.0             31d
   rendered-master-3e88ec72aed3886dec061df60d16d1af            02c07496ba0417b3e12b78fb32baf6293d314f79   3.2.0             31d
   rendered-master-419bee7de96134963a15fdf9dd473b25            365c1cfd14de5b0e3b85e0fc815b0060f36ab955   3.2.0             17d
   rendered-master-53f5c91c7661708adce18739cc0f40fb            365c1cfd14de5b0e3b85e0fc815b0060f36ab955   3.2.0             13d
   rendered-master-a6a357ec18e5bce7f5ac426fc7c5ffcd            365c1cfd14de5b0e3b85e0fc815b0060f36ab955   3.2.0             7d3h
   rendered-master-dc7f874ec77fc4b969674204332da037            5b6fb8349a29735e48446d435962dec4547d3090   3.2.0             31d
   rendered-worker-1a75960c52ad18ff5dfa6674eb7e533d            5b6fb8349a29735e48446d435962dec4547d3090   3.2.0             31d
   rendered-worker-2640531be11ba43c61d72e82dc634ce6            5b6fb8349a29735e48446d435962dec4547d3090   3.2.0             31d
   rendered-worker-4e48906dca84ee702959c71a53ee80e7            365c1cfd14de5b0e3b85e0fc815b0060f36ab955   3.2.0             7d3h
   rendered-worker-4f110718fe88e5f349987854a1147755            365c1cfd14de5b0e3b85e0fc815b0060f36ab955   3.2.0             17d
   rendered-worker-afc758e194d6188677eb837842d3b379            02c07496ba0417b3e12b78fb32baf6293d314f79   3.2.0             31d
   rendered-worker-daa08cc1e8f5fcdeba24de60cd955cc3            365c1cfd14de5b0e3b85e0fc815b0060f36ab955   3.2.0             13d

   You should see a new machine config, with the rendered-infra-* prefix.

5. Optional: To deploy changes to a custom pool, create a machine config that uses the custom pool name as the label, such as infra. Note that this is not required and only shown for instructional purposes. In this manner, you can apply any custom configurations specific to only your infra nodes.

   Note

   After you create the new machine config pool, the MCO generates a new rendered config for that pool, and associated nodes of that pool reboot to apply the new configuration.

   1. Create a machine config:

      $ cat infra.mc.yaml

      Example output

      apiVersion: machineconfiguration.openshift.io/v1
      kind: MachineConfig
      metadata:
        name: 51-infra
        labels:
          machineconfiguration.openshift.io/role: infra 1
      spec:
        config:
          ignition:
            version: 3.2.0
          storage:
            files:
            - path: /etc/infratest
              mode: 0644
              contents:
                source: data:,infra

      1

      Add the label you added to the node as a nodeSelector.

   2. Apply the machine config to the infra-labeled nodes:

      $ oc create -f infra.mc.yaml

6. Confirm that your new machine config pool is available:

   $ oc get mcp

   Example output

   NAME     CONFIG                                             UPDATED   UPDATING   DEGRADED   MACHINECOUNT   READYMACHINECOUNT   UPDATEDMACHINECOUNT   DEGRADEDMACHINECOUNT   AGE
   infra    rendered-infra-60e35c2e99f42d976e084fa94da4d0fc    True      False      False      1              1                   1                     0                      4m20s
   master   rendered-master-9360fdb895d4c131c7c4bebbae099c90   True      False      False      3              3                   3                     0                      91m
   worker   rendered-worker-60e35c2e99f42d976e084fa94da4d0fc   True      False      False      2              2                   2                     0                      91m

   In this example, a worker node was changed to an infra node.

Procedure

1. Add a taint to the infra node to prevent scheduling user workloads on it:

   1. Determine if the node has the taint:

      $ oc describe nodes <node_name>

      Sample output

      oc describe node ci-ln-iyhx092-f76d1-nvdfm-worker-b-wln2l
      Name:               ci-ln-iyhx092-f76d1-nvdfm-worker-b-wln2l
      Roles:              worker
       ...
      Taints:             node-role.kubernetes.io/infra:NoSchedule
       ...

      This example shows that the node has a taint. You can proceed with adding a toleration to your pod in the next step.

   2. If you have not configured a taint to prevent scheduling user workloads on it:

      $ oc adm taint nodes <node_name> <key>=<value>:<effect>

      For example:

      $ oc adm taint nodes node1 node-role.kubernetes.io/infra=reserved:NoSchedule

      Tip

      You can alternatively apply the following YAML to add the taint:

      kind: Node
      apiVersion: v1
      metadata:
        name: <node_name>
        labels:
          ...
      spec:
        taints:
          - key: node-role.kubernetes.io/infra
            effect: NoSchedule
            value: reserved
        ...

      This example places a taint on node1 that has key node-role.kubernetes.io/infra and taint effect NoSchedule. Nodes with the NoSchedule effect schedule only pods that tolerate the taint, but allow existing pods to remain scheduled on the node.

      Note

      If a descheduler is used, pods violating node taints could be evicted from the cluster.

   3. Add the taint with NoExecute Effect along with the above taint with NoSchedule Effect:

      $ oc adm taint nodes <node_name> <key>=<value>:<effect>

      For example:

      $ oc adm taint nodes node1 node-role.kubernetes.io/infra=reserved:NoExecute

      Tip

      You can alternatively apply the following YAML to add the taint:

      kind: Node
      apiVersion: v1
      metadata:
        name: <node_name>
        labels:
          ...
      spec:
        taints:
          - key: node-role.kubernetes.io/infra
            effect: NoExecute
            value: reserved
        ...

      This example places a taint on node1 that has the key node-role.kubernetes.io/infra and taint effect NoExecute. Nodes with the NoExecute effect schedule only pods that tolerate the taint. The effect will remove any existing pods from the node that do not have a matching toleration.

2. Add tolerations for the pod configurations you want to schedule on the infra node, like router, registry, and monitoring workloads. Add the following code to the Pod object specification:

   tolerations:
     - effect: NoSchedule 1
       key: node-role.kubernetes.io/infra 2
       value: reserved 3
     - effect: NoExecute 4
       key: node-role.kubernetes.io/infra 5
       operator: Exists 6
       value: reserved 7

   1

   Specify the effect that you added to the node.

   2

   Specify the key that you added to the node.

   3

   Specify the value of the key-value pair taint that you added to the node.

   4

   Specify the effect that you added to the node.

   5

   Specify the key that you added to the node.

   6

   Specify the Exists Operator to require a taint with the key node-role.kubernetes.io/infra to be present on the node.

   7

   Specify the value of the key-value pair taint that you added to the node.

   This toleration matches the taint created by the oc adm taint command. A pod with this toleration can be scheduled onto the infra node.

   Note

   Moving pods for an Operator installed via OLM to an infra node is not always possible. The capability to move Operator pods depends on the configuration of each Operator.

3. Schedule the pod to the infra node using a scheduler. See the documentation for Controlling pod placement onto nodes for details.

Procedure

1. View the IngressController custom resource for the router Operator:

   $ oc get ingresscontroller default -n openshift-ingress-operator -o yaml

   The command output resembles the following text:

   apiVersion: operator.openshift.io/v1
   kind: IngressController
   metadata:
     creationTimestamp: 2019-04-18T12:35:39Z
     finalizers:
     - ingresscontroller.operator.openshift.io/finalizer-ingresscontroller
     generation: 1
     name: default
     namespace: openshift-ingress-operator
     resourceVersion: "11341"
     selfLink: /apis/operator.openshift.io/v1/namespaces/openshift-ingress-operator/ingresscontrollers/default
     uid: 79509e05-61d6-11e9-bc55-02ce4781844a
   spec: {}
   status:
     availableReplicas: 2
     conditions:
     - lastTransitionTime: 2019-04-18T12:36:15Z
       status: "True"
       type: Available
     domain: apps.<cluster>.example.com
     endpointPublishingStrategy:
       type: LoadBalancerService
     selector: ingresscontroller.operator.openshift.io/deployment-ingresscontroller=default

2. Edit the ingresscontroller resource and change the nodeSelector to use the infra label:

   $ oc edit ingresscontroller default -n openshift-ingress-operator

     spec:
       nodePlacement:
         nodeSelector: 1
           matchLabels:
             node-role.kubernetes.io/infra: ""
         tolerations:
         - effect: NoSchedule
           key: node-role.kubernetes.io/infra
           value: reserved
         - effect: NoExecute
           key: node-role.kubernetes.io/infra
           value: reserved

   1

   Add a nodeSelector parameter with the appropriate value to the component you want to move. You can use a nodeSelector in the format shown or use <key>: <value> pairs, based on the value specified for the node. If you added a taint to the infrastructure node, also add a matching toleration.

3. Confirm that the router pod is running on the infra node.

   1. View the list of router pods and note the node name of the running pod:

      $ oc get pod -n openshift-ingress -o wide

      Example output

      NAME                              READY     STATUS        RESTARTS   AGE       IP           NODE                           NOMINATED NODE   READINESS GATES
      router-default-86798b4b5d-bdlvd   1/1      Running       0          28s       10.130.2.4   ip-10-0-217-226.ec2.internal   <none>           <none>
      router-default-955d875f4-255g8    0/1      Terminating   0          19h       10.129.2.4   ip-10-0-148-172.ec2.internal   <none>           <none>

      In this example, the running pod is on the ip-10-0-217-226.ec2.internal node.

   2. View the node status of the running pod:

      $ oc get node <node_name> 1

      1

      Specify the <node_name> that you obtained from the pod list.

      Example output

      NAME                          STATUS  ROLES         AGE   VERSION
      ip-10-0-217-226.ec2.internal  Ready   infra,worker  17h   v1.26.0

      Because the role list includes infra, the pod is running on the correct node.

Procedure

1. View the config/instance object:

   $ oc get configs.imageregistry.operator.openshift.io/cluster -o yaml

   Example output

   apiVersion: imageregistry.operator.openshift.io/v1
   kind: Config
   metadata:
     creationTimestamp: 2019-02-05T13:52:05Z
     finalizers:
     - imageregistry.operator.openshift.io/finalizer
     generation: 1
     name: cluster
     resourceVersion: "56174"
     selfLink: /apis/imageregistry.operator.openshift.io/v1/configs/cluster
     uid: 36fd3724-294d-11e9-a524-12ffeee2931b
   spec:
     httpSecret: d9a012ccd117b1e6616ceccb2c3bb66a5fed1b5e481623
     logging: 2
     managementState: Managed
     proxy: {}
     replicas: 1
     requests:
       read: {}
       write: {}
     storage:
       s3:
         bucket: image-registry-us-east-1-c92e88cad85b48ec8b312344dff03c82-392c
         region: us-east-1
   status:
   ...

2. Edit the config/instance object:

   $ oc edit configs.imageregistry.operator.openshift.io/cluster

   spec:
     affinity:
       podAntiAffinity:
         preferredDuringSchedulingIgnoredDuringExecution:
         - podAffinityTerm:
             namespaces:
             - openshift-image-registry
             topologyKey: kubernetes.io/hostname
           weight: 100
     logLevel: Normal
     managementState: Managed
     nodeSelector: 1
       node-role.kubernetes.io/infra: ""
     tolerations:
     - effect: NoSchedule
       key: node-role.kubernetes.io/infra
       value: reserved
     - effect: NoExecute
       key: node-role.kubernetes.io/infra
       value: reserved

   1

   Add a nodeSelector parameter with the appropriate value to the component you want to move. You can use a nodeSelector in the format shown or use <key>: <value> pairs, based on the value specified for the node. If you added a taint to the infrasructure node, also add a matching toleration.

3. Verify the registry pod has been moved to the infrastructure node.

   1. Run the following command to identify the node where the registry pod is located:

      $ oc get pods -o wide -n openshift-image-registry

   2. Confirm the node has the label you specified:

      $ oc describe node <node_name>

      Review the command output and confirm that node-role.kubernetes.io/infra is in the LABELS list.

Procedure

1. Edit the cluster-monitoring-config config map and change the nodeSelector to use the infra label:

   $ oc edit configmap cluster-monitoring-config -n openshift-monitoring

   apiVersion: v1
   kind: ConfigMap
   metadata:
     name: cluster-monitoring-config
     namespace: openshift-monitoring
   data:
     config.yaml: |+
       alertmanagerMain:
         nodeSelector: 1
           node-role.kubernetes.io/infra: ""
         tolerations:
         - key: node-role.kubernetes.io/infra
           value: reserved
           effect: NoSchedule
         - key: node-role.kubernetes.io/infra
           value: reserved
           effect: NoExecute
       prometheusK8s:
         nodeSelector:
           node-role.kubernetes.io/infra: ""
         tolerations:
         - key: node-role.kubernetes.io/infra
           value: reserved
           effect: NoSchedule
         - key: node-role.kubernetes.io/infra
           value: reserved
           effect: NoExecute
       prometheusOperator:
         nodeSelector:
           node-role.kubernetes.io/infra: ""
         tolerations:
         - key: node-role.kubernetes.io/infra
           value: reserved
           effect: NoSchedule
         - key: node-role.kubernetes.io/infra
           value: reserved
           effect: NoExecute
       k8sPrometheusAdapter:
         nodeSelector:
           node-role.kubernetes.io/infra: ""
         tolerations:
         - key: node-role.kubernetes.io/infra
           value: reserved
           effect: NoSchedule
         - key: node-role.kubernetes.io/infra
           value: reserved
           effect: NoExecute
       kubeStateMetrics:
         nodeSelector:
           node-role.kubernetes.io/infra: ""
         tolerations:
         - key: node-role.kubernetes.io/infra
           value: reserved
           effect: NoSchedule
         - key: node-role.kubernetes.io/infra
           value: reserved
           effect: NoExecute
       telemeterClient:
         nodeSelector:
           node-role.kubernetes.io/infra: ""
         tolerations:
         - key: node-role.kubernetes.io/infra
           value: reserved
           effect: NoSchedule
         - key: node-role.kubernetes.io/infra
           value: reserved
           effect: NoExecute
       openshiftStateMetrics:
         nodeSelector:
           node-role.kubernetes.io/infra: ""
         tolerations:
         - key: node-role.kubernetes.io/infra
           value: reserved
           effect: NoSchedule
         - key: node-role.kubernetes.io/infra
           value: reserved
           effect: NoExecute
       thanosQuerier:
         nodeSelector:
           node-role.kubernetes.io/infra: ""
         tolerations:
         - key: node-role.kubernetes.io/infra
           value: reserved
           effect: NoSchedule
         - key: node-role.kubernetes.io/infra
           value: reserved
           effect: NoExecute

   1

   Add a nodeSelector parameter with the appropriate value to the component you want to move. You can use a nodeSelector in the format shown or use <key>: <value> pairs, based on the value specified for the node. If you added a taint to the infrasructure node, also add a matching toleration.

2. Watch the monitoring pods move to the new machines:

   $ watch 'oc get pod -n openshift-monitoring -o wide'

3. If a component has not moved to the infra node, delete the pod with this component:

   $ oc delete pod -n openshift-monitoring <pod>

   The component from the deleted pod is re-created on the infra node.

1. In the OpenShift Container Platform web console, switch to the Administration → Custom Resource Definitions page.
2. On the Custom Resource Definitions page, click FeatureGate.
3. On the Custom Resource Definition Details page, click the Instances tab.
4. Click the cluster feature gate, then click the YAML tab.

5. Edit the cluster instance to add specific feature sets:

   Warning

   Enabling the TechPreviewNoUpgrade feature set on your cluster cannot be undone and prevents minor version updates. You should not enable this feature set on production clusters.

   Sample Feature Gate custom resource

   apiVersion: config.openshift.io/v1
   kind: FeatureGate
   metadata:
     name: cluster 1
   # ...
   spec:
     featureSet: TechPreviewNoUpgrade 2

   1

   The name of the FeatureGate CR must be cluster.

   2

   Add the feature set that you want to enable:

   • TechPreviewNoUpgrade enables specific Technology Preview features.

   After you save the changes, new machine configs are created, the machine config pools are updated, and scheduling on each node is disabled while the change is being applied.

1. From the Administrator perspective in the web console, navigate to Compute → Nodes.
2. Select a node.
3. In the Node details page, click Terminal.

4. In the terminal window, change your root directory to /host:

   sh-4.2# chroot /host

5. View the kubelet.conf file:

   sh-4.2# cat /etc/kubernetes/kubelet.conf

   Sample output

   # ...
   featureGates:
     InsightsOperatorPullingSCA: true,
     LegacyNodeRoleBehavior: false
   # ...

   The features that are listed as true are enabled on your cluster.

   Note

   The features listed vary depending upon the OpenShift Container Platform version.

1. Edit the FeatureGate CR named cluster:

   $ oc edit featuregate cluster

   Warning

   Enabling the TechPreviewNoUpgrade feature set on your cluster cannot be undone and prevents minor version updates. You should not enable this feature set on production clusters.

   Sample FeatureGate custom resource

   apiVersion: config.openshift.io/v1
   kind: FeatureGate
   metadata:
     name: cluster 1
   # ...
   spec:
     featureSet: TechPreviewNoUpgrade 2

   1

   The name of the FeatureGate CR must be cluster.

   2

   Add the feature set that you want to enable:

   • TechPreviewNoUpgrade enables specific Technology Preview features.

   After you save the changes, new machine configs are created, the machine config pools are updated, and scheduling on each node is disabled while the change is being applied.

1. From the Administrator perspective in the web console, navigate to Compute → Nodes.
2. Select a node.
3. In the Node details page, click Terminal.

4. In the terminal window, change your root directory to /host:

   sh-4.2# chroot /host

5. View the kubelet.conf file:

   sh-4.2# cat /etc/kubernetes/kubelet.conf

   Sample output

   # ...
   featureGates:
     InsightsOperatorPullingSCA: true,
     LegacyNodeRoleBehavior: false
   # ...

   The features that are listed as true are enabled on your cluster.

   Note

   The features listed vary depending upon the OpenShift Container Platform version.

Procedure

1. Modify the APIServer object:

   $ oc edit apiserver

2. Set the spec.encryption.type field to aesgcm or aescbc:

   spec:
     encryption:
       type: aesgcm 1

   1

   Set to aesgcm for AES-GCM encryption or aescbc for AES-CBC encryption.

3. Save the file to apply the changes.

   The encryption process starts. It can take 20 minutes or longer for this process to complete, depending on the size of the etcd database.

4. Verify that etcd encryption was successful.

   1. Review the Encrypted status condition for the OpenShift API server to verify that its resources were successfully encrypted:

      $ oc get openshiftapiserver -o=jsonpath='{range .items[0].status.conditions[?(@.type=="Encrypted")]}{.reason}{"\n"}{.message}{"\n"}'

      The output shows EncryptionCompleted upon successful encryption:

      EncryptionCompleted
      All resources encrypted: routes.route.openshift.io

      If the output shows EncryptionInProgress, encryption is still in progress. Wait a few minutes and try again.

   2. Review the Encrypted status condition for the Kubernetes API server to verify that its resources were successfully encrypted:

      $ oc get kubeapiserver -o=jsonpath='{range .items[0].status.conditions[?(@.type=="Encrypted")]}{.reason}{"\n"}{.message}{"\n"}'

      The output shows EncryptionCompleted upon successful encryption:

      EncryptionCompleted
      All resources encrypted: secrets, configmaps

      If the output shows EncryptionInProgress, encryption is still in progress. Wait a few minutes and try again.

   3. Review the Encrypted status condition for the OpenShift OAuth API server to verify that its resources were successfully encrypted:

      $ oc get authentication.operator.openshift.io -o=jsonpath='{range .items[0].status.conditions[?(@.type=="Encrypted")]}{.reason}{"\n"}{.message}{"\n"}'

      The output shows EncryptionCompleted upon successful encryption:

      EncryptionCompleted
      All resources encrypted: oauthaccesstokens.oauth.openshift.io, oauthauthorizetokens.oauth.openshift.io

      If the output shows EncryptionInProgress, encryption is still in progress. Wait a few minutes and try again.

Procedure

1. Modify the APIServer object:

   $ oc edit apiserver

2. Set the encryption field type to identity:

   spec:
     encryption:
       type: identity 1

   1

   The identity type is the default value and means that no encryption is performed.

3. Save the file to apply the changes.

   The decryption process starts. It can take 20 minutes or longer for this process to complete, depending on the size of your cluster.

4. Verify that etcd decryption was successful.

   1. Review the Encrypted status condition for the OpenShift API server to verify that its resources were successfully decrypted:

      $ oc get openshiftapiserver -o=jsonpath='{range .items[0].status.conditions[?(@.type=="Encrypted")]}{.reason}{"\n"}{.message}{"\n"}'

      The output shows DecryptionCompleted upon successful decryption:

      DecryptionCompleted
      Encryption mode set to identity and everything is decrypted

      If the output shows DecryptionInProgress, decryption is still in progress. Wait a few minutes and try again.

   2. Review the Encrypted status condition for the Kubernetes API server to verify that its resources were successfully decrypted:

      $ oc get kubeapiserver -o=jsonpath='{range .items[0].status.conditions[?(@.type=="Encrypted")]}{.reason}{"\n"}{.message}{"\n"}'

      The output shows DecryptionCompleted upon successful decryption:

      DecryptionCompleted
      Encryption mode set to identity and everything is decrypted

      If the output shows DecryptionInProgress, decryption is still in progress. Wait a few minutes and try again.

   3. Review the Encrypted status condition for the OpenShift OAuth API server to verify that its resources were successfully decrypted:

      $ oc get authentication.operator.openshift.io -o=jsonpath='{range .items[0].status.conditions[?(@.type=="Encrypted")]}{.reason}{"\n"}{.message}{"\n"}'

      The output shows DecryptionCompleted upon successful decryption:

      DecryptionCompleted
      Encryption mode set to identity and everything is decrypted

      If the output shows DecryptionInProgress, decryption is still in progress. Wait a few minutes and try again.

Procedure

1. Start a debug session as root for a control plane node:

   $ oc debug --as-root node/<node_name>

2. Change your root directory to /host in the debug shell:

   sh-4.4# chroot /host

3. If the cluster-wide proxy is enabled, export the NO_PROXY, HTTP_PROXY, and HTTPS_PROXY environment variables by running the following commands:

   $ export HTTP_PROXY=http://<your_proxy.example.com>:8080

   $ export HTTPS_PROXY=https://<your_proxy.example.com>:8080

   $ export NO_PROXY=<example.com>

4. Run the cluster-backup.sh script in the debug shell and pass in the location to save the backup to.

   Tip

   The cluster-backup.sh script is maintained as a component of the etcd Cluster Operator and is a wrapper around the etcdctl snapshot save command.

   sh-4.4# /usr/local/bin/cluster-backup.sh /home/core/assets/backup

   Example script output

   found latest kube-apiserver: /etc/kubernetes/static-pod-resources/kube-apiserver-pod-6
   found latest kube-controller-manager: /etc/kubernetes/static-pod-resources/kube-controller-manager-pod-7
   found latest kube-scheduler: /etc/kubernetes/static-pod-resources/kube-scheduler-pod-6
   found latest etcd: /etc/kubernetes/static-pod-resources/etcd-pod-3
   ede95fe6b88b87ba86a03c15e669fb4aa5bf0991c180d3c6895ce72eaade54a1
   etcdctl version: 3.4.14
   API version: 3.4
   {"level":"info","ts":1624647639.0188997,"caller":"snapshot/v3_snapshot.go:119","msg":"created temporary db file","path":"/home/core/assets/backup/snapshot_2021-06-25_190035.db.part"}
   {"level":"info","ts":"2021-06-25T19:00:39.030Z","caller":"clientv3/maintenance.go:200","msg":"opened snapshot stream; downloading"}
   {"level":"info","ts":1624647639.0301006,"caller":"snapshot/v3_snapshot.go:127","msg":"fetching snapshot","endpoint":"https://10.0.0.5:2379"}
   {"level":"info","ts":"2021-06-25T19:00:40.215Z","caller":"clientv3/maintenance.go:208","msg":"completed snapshot read; closing"}
   {"level":"info","ts":1624647640.6032252,"caller":"snapshot/v3_snapshot.go:142","msg":"fetched snapshot","endpoint":"https://10.0.0.5:2379","size":"114 MB","took":1.584090459}
   {"level":"info","ts":1624647640.6047094,"caller":"snapshot/v3_snapshot.go:152","msg":"saved","path":"/home/core/assets/backup/snapshot_2021-06-25_190035.db"}
   Snapshot saved at /home/core/assets/backup/snapshot_2021-06-25_190035.db
   {"hash":3866667823,"revision":31407,"totalKey":12828,"totalSize":114446336}
   snapshot db and kube resources are successfully saved to /home/core/assets/backup

   In this example, two files are created in the /home/core/assets/backup/ directory on the control plane host:

   • snapshot_<datetimestamp>.db: This file is the etcd snapshot. The cluster-backup.sh script confirms its validity.

   • static_kuberesources_<datetimestamp>.tar.gz: This file contains the resources for the static pods. If etcd encryption is enabled, it also contains the encryption keys for the etcd snapshot.

     Note

     If etcd encryption is enabled, it is recommended to store this second file separately from the etcd snapshot for security reasons. However, this file is required to restore from the etcd snapshot.

     Keep in mind that etcd encryption only encrypts values, not keys. This means that resource types, namespaces, and object names are unencrypted.

Procedure

1. Select a control plane host to use as the recovery host. This is the host that you will run the restore operation on.

2. Establish SSH connectivity to each of the control plane nodes, including the recovery host.

   The Kubernetes API server becomes inaccessible after the restore process starts, so you cannot access the control plane nodes. For this reason, it is recommended to establish SSH connectivity to each control plane host in a separate terminal.

   Important

   If you do not complete this step, you will not be able to access the control plane hosts to complete the restore procedure, and you will be unable to recover your cluster from this state.

3. Copy the etcd backup directory to the recovery control plane host.

   This procedure assumes that you copied the backup directory containing the etcd snapshot and the resources for the static pods to the /home/core/ directory of your recovery control plane host.

4. Stop the static pods on any other control plane nodes.

   Note

   You do not need to stop the static pods on the recovery host.

   1. Access a control plane host that is not the recovery host.

   2. Move the existing etcd pod file out of the kubelet manifest directory:

      $ sudo mv -v /etc/kubernetes/manifests/etcd-pod.yaml /tmp

   3. Verify that the etcd pods are stopped.

      $ sudo crictl ps | grep etcd | egrep -v "operator|etcd-guard"

      The output of this command should be empty. If it is not empty, wait a few minutes and check again.

   4. Move the existing Kubernetes API server pod file out of the kubelet manifest directory:

      $ sudo mv -v /etc/kubernetes/manifests/kube-apiserver-pod.yaml /tmp

   5. Verify that the Kubernetes API server pods are stopped.

      $ sudo crictl ps | grep kube-apiserver | egrep -v "operator|guard"

      The output of this command should be empty. If it is not empty, wait a few minutes and check again.

   6. Move the etcd data directory to a different location:

      $ sudo mv -v /var/lib/etcd/ /tmp

   7. If the /etc/kubernetes/manifests/keepalived.yaml file exists and the node is deleted, follow these steps:

      1. Move the /etc/kubernetes/manifests/keepalived.yaml file out of the kubelet manifest directory:

         $ sudo mv -v /etc/kubernetes/manifests/keepalived.yaml /tmp

      2. Verify that any containers managed by the keepalived daemon are stopped:

         $ sudo crictl ps --name keepalived

         The output of this command should be empty. If it is not empty, wait a few minutes and check again.

      3. Check if the control plane has any Virtual IPs (VIPs) assigned to it:

         $ ip -o address | egrep '<api_vip>|<ingress_vip>'

      4. For each reported VIP, run the following command to remove it:

         $ sudo ip address del <reported_vip> dev <reported_vip_device>

   8. Repeat this step on each of the other control plane hosts that is not the recovery host.
5. Access the recovery control plane host.

6. If the keepalived daemon is in use, verify that the recovery control plane node owns the VIP:

   $ ip -o address | grep <api_vip>

   The address of the VIP is highlighted in the output if it exists. This command returns an empty string if the VIP is not set or configured incorrectly.

7. If the cluster-wide proxy is enabled, be sure that you have exported the NO_PROXY, HTTP_PROXY, and HTTPS_PROXY environment variables.

   Tip

   You can check whether the proxy is enabled by reviewing the output of oc get proxy cluster -o yaml. The proxy is enabled if the httpProxy, httpsProxy, and noProxy fields have values set.

8. Run the restore script on the recovery control plane host and pass in the path to the etcd backup directory:

   $ sudo -E /usr/local/bin/cluster-restore.sh /home/core/assets/backup

   Example script output

   ...stopping kube-scheduler-pod.yaml
   ...stopping kube-controller-manager-pod.yaml
   ...stopping etcd-pod.yaml
   ...stopping kube-apiserver-pod.yaml
   Waiting for container etcd to stop
   .complete
   Waiting for container etcdctl to stop
   .............................complete
   Waiting for container etcd-metrics to stop
   complete
   Waiting for container kube-controller-manager to stop
   complete
   Waiting for container kube-apiserver to stop
   ..........................................................................................complete
   Waiting for container kube-scheduler to stop
   complete
   Moving etcd data-dir /var/lib/etcd/member to /var/lib/etcd-backup
   starting restore-etcd static pod
   starting kube-apiserver-pod.yaml
   static-pod-resources/kube-apiserver-pod-7/kube-apiserver-pod.yaml
   starting kube-controller-manager-pod.yaml
   static-pod-resources/kube-controller-manager-pod-7/kube-controller-manager-pod.yaml
   starting kube-scheduler-pod.yaml
   static-pod-resources/kube-scheduler-pod-8/kube-scheduler-pod.yaml

   Note

   The restore process can cause nodes to enter the NotReady state if the node certificates were updated after the last etcd backup.

9. Check the nodes to ensure they are in the Ready state.

   1. Run the following command:

      $ oc get nodes -w

      Sample output

      NAME                STATUS  ROLES          AGE     VERSION
      host-172-25-75-28   Ready   master         3d20h   v1.26.0
      host-172-25-75-38   Ready   infra,worker   3d20h   v1.26.0
      host-172-25-75-40   Ready   master         3d20h   v1.26.0
      host-172-25-75-65   Ready   master         3d20h   v1.26.0
      host-172-25-75-74   Ready   infra,worker   3d20h   v1.26.0
      host-172-25-75-79   Ready   worker         3d20h   v1.26.0
      host-172-25-75-86   Ready   worker         3d20h   v1.26.0
      host-172-25-75-98   Ready   infra,worker   3d20h   v1.26.0

      It can take several minutes for all nodes to report their state.

   2. If any nodes are in the NotReady state, log in to the nodes and remove all of the PEM files from the /var/lib/kubelet/pki directory on each node. You can SSH into the nodes or use the terminal window in the web console.

      $  ssh -i <ssh-key-path> core@<master-hostname>

      Sample pki directory

      sh-4.4# pwd
      /var/lib/kubelet/pki
      sh-4.4# ls
      kubelet-client-2022-04-28-11-24-09.pem  kubelet-server-2022-04-28-11-24-15.pem
      kubelet-client-current.pem              kubelet-server-current.pem

10. Restart the kubelet service on all control plane hosts.

    1. From the recovery host, run the following command:

       $ sudo systemctl restart kubelet.service

    2. Repeat this step on all other control plane hosts.

11. Approve the pending CSRs:

    Note

    Clusters with no worker nodes, such as single-node clusters or clusters consisting of three schedulable control plane nodes, will not have any pending CSRs to approve. You can skip all the commands listed in this step.

    1. Get the list of current CSRs:

       $ oc get csr

       Example output

       NAME        AGE    SIGNERNAME                                    REQUESTOR                                                                   CONDITION
       csr-2s94x   8m3s   kubernetes.io/kubelet-serving                 system:node:<node_name>                                                     Pending 1
       csr-4bd6t   8m3s   kubernetes.io/kubelet-serving                 system:node:<node_name>                                                     Pending 2
       csr-4hl85   13m    kubernetes.io/kube-apiserver-client-kubelet   system:serviceaccount:openshift-machine-config-operator:node-bootstrapper   Pending 3
       csr-zhhhp   3m8s   kubernetes.io/kube-apiserver-client-kubelet   system:serviceaccount:openshift-machine-config-operator:node-bootstrapper   Pending 4
       ...

       1 1 2

       A pending kubelet service CSR (for user-provisioned installations).

       3 4

       A pending node-bootstrapper CSR.

    2. Review the details of a CSR to verify that it is valid:

       $ oc describe csr <csr_name> 1

       1

       <csr_name> is the name of a CSR from the list of current CSRs.

    3. Approve each valid node-bootstrapper CSR:

       $ oc adm certificate approve <csr_name>

    4. For user-provisioned installations, approve each valid kubelet service CSR:

       $ oc adm certificate approve <csr_name>

12. Verify that the single member control plane has started successfully.

    1. From the recovery host, verify that the etcd container is running.

       $ sudo crictl ps | grep etcd | egrep -v "operator|etcd-guard"

       Example output

       3ad41b7908e32       36f86e2eeaaffe662df0d21041eb22b8198e0e58abeeae8c743c3e6e977e8009                                                         About a minute ago   Running             etcd                                          0                   7c05f8af362f0

    2. From the recovery host, verify that the etcd pod is running.

       $ oc -n openshift-etcd get pods -l k8s-app=etcd

       Example output

       NAME                                             READY   STATUS      RESTARTS   AGE
       etcd-ip-10-0-143-125.ec2.internal                1/1     Running     1          2m47s

       If the status is Pending, or the output lists more than one running etcd pod, wait a few minutes and check again.

13. If you are using the OVNKubernetes network plugin, delete the node objects that are associated with control plane hosts that are not the recovery control plane host.

    $ oc delete node <non-recovery-controlplane-host-1> <non-recovery-controlplane-host-2>

14. Verify that the Cluster Network Operator (CNO) redeploys the OVN-Kubernetes control plane and that it no longer references the non-recovery controller IP addresses. To verify this result, regularly check the output of the following command. Wait until it returns an empty result before you proceed to restart the Open Virtual Network (OVN) Kubernetes pods on all of the hosts in the next step.

    $ oc -n openshift-ovn-kubernetes get ds/ovnkube-master -o yaml | grep -E '<non-recovery_controller_ip_1>|<non-recovery_controller_ip_2>'

    Note

    It can take at least 5-10 minutes for the OVN-Kubernetes control plane to be redeployed and the previous command to return empty output.

15. If you are using the OVN-Kubernetes network plugin, restart the Open Virtual Network (OVN) Kubernetes pods on all of the hosts.

    Note

    Validating and mutating admission webhooks can reject pods. If you add any additional webhooks with the failurePolicy set to Fail, then they can reject pods and the restoration process can fail. You can avoid this by saving and deleting webhooks while restoring the cluster state. After the cluster state is restored successfully, you can enable the webhooks again.

    Alternatively, you can temporarily set the failurePolicy to Ignore while restoring the cluster state. After the cluster state is restored successfully, you can set the failurePolicy to Fail.

    1. Remove the northbound database (nbdb) and southbound database (sbdb). Access the recovery host and the remaining control plane nodes by using Secure Shell (SSH) and run the following command:

       $ sudo rm -f /var/lib/ovn/etc/*.db

    2. Delete all OVN-Kubernetes control plane pods by running the following command:

       $ oc delete pods -l app=ovnkube-master -n openshift-ovn-kubernetes

    3. Ensure that any OVN-Kubernetes control plane pods are deployed again and are in a Running state by running the following command:

       $ oc get pods -l app=ovnkube-master -n openshift-ovn-kubernetes

       Example output

       NAME                   READY   STATUS    RESTARTS   AGE
       ovnkube-master-nb24h   4/4     Running   0          48s

    4. Delete all ovnkube-node pods by running the following command:

       $ oc get pods -n openshift-ovn-kubernetes -o name | grep ovnkube-node | while read p ; do oc delete $p -n openshift-ovn-kubernetes ; done

    5. Ensure that all the ovnkube-node pods are deployed again and are in a Running state by running the following command:

       $ oc get  pods -n openshift-ovn-kubernetes | grep ovnkube-node

16. Delete and re-create other non-recovery, control plane machines, one by one. After the machines are re-created, a new revision is forced and etcd automatically scales up.

    • If you use a user-provisioned bare metal installation, you can re-create a control plane machine by using the same method that you used to originally create it. For more information, see "Installing a user-provisioned cluster on bare metal".

      Warning

      Do not delete and re-create the machine for the recovery host.

    • If you are running installer-provisioned infrastructure, or you used the Machine API to create your machines, follow these steps:

      Warning

      Do not delete and re-create the machine for the recovery host.

      For bare metal installations on installer-provisioned infrastructure, control plane machines are not re-created. For more information, see "Replacing a bare-metal control plane node".

      1. Obtain the machine for one of the lost control plane hosts.

         In a terminal that has access to the cluster as a cluster-admin user, run the following command:

         $ oc get machines -n openshift-machine-api -o wide

         Example output:

         NAME                                        PHASE     TYPE        REGION      ZONE         AGE     NODE                           PROVIDERID                              STATE
         clustername-8qw5l-master-0                  Running   m4.xlarge   us-east-1   us-east-1a   3h37m   ip-10-0-131-183.ec2.internal   aws:///us-east-1a/i-0ec2782f8287dfb7e   stopped 1
         clustername-8qw5l-master-1                  Running   m4.xlarge   us-east-1   us-east-1b   3h37m   ip-10-0-143-125.ec2.internal   aws:///us-east-1b/i-096c349b700a19631   running
         clustername-8qw5l-master-2                  Running   m4.xlarge   us-east-1   us-east-1c   3h37m   ip-10-0-154-194.ec2.internal    aws:///us-east-1c/i-02626f1dba9ed5bba  running
         clustername-8qw5l-worker-us-east-1a-wbtgd   Running   m4.large    us-east-1   us-east-1a   3h28m   ip-10-0-129-226.ec2.internal   aws:///us-east-1a/i-010ef6279b4662ced   running
         clustername-8qw5l-worker-us-east-1b-lrdxb   Running   m4.large    us-east-1   us-east-1b   3h28m   ip-10-0-144-248.ec2.internal   aws:///us-east-1b/i-0cb45ac45a166173b   running
         clustername-8qw5l-worker-us-east-1c-pkg26   Running   m4.large    us-east-1   us-east-1c   3h28m   ip-10-0-170-181.ec2.internal   aws:///us-east-1c/i-06861c00007751b0a   running

         1

         This is the control plane machine for the lost control plane host, ip-10-0-131-183.ec2.internal.

      2. Delete the machine of the lost control plane host by running:

         $ oc delete machine -n openshift-machine-api clustername-8qw5l-master-0 1

         1

         Specify the name of the control plane machine for the lost control plane host.

         A new machine is automatically provisioned after deleting the machine of the lost control plane host.

      3. Verify that a new machine has been created by running:

         $ oc get machines -n openshift-machine-api -o wide

         Example output:

         NAME                                        PHASE          TYPE        REGION      ZONE         AGE     NODE                           PROVIDERID                              STATE
         clustername-8qw5l-master-1                  Running        m4.xlarge   us-east-1   us-east-1b   3h37m   ip-10-0-143-125.ec2.internal   aws:///us-east-1b/i-096c349b700a19631   running
         clustername-8qw5l-master-2                  Running        m4.xlarge   us-east-1   us-east-1c   3h37m   ip-10-0-154-194.ec2.internal    aws:///us-east-1c/i-02626f1dba9ed5bba  running
         clustername-8qw5l-master-3                  Provisioning   m4.xlarge   us-east-1   us-east-1a   85s     ip-10-0-173-171.ec2.internal    aws:///us-east-1a/i-015b0888fe17bc2c8  running 1
         clustername-8qw5l-worker-us-east-1a-wbtgd   Running        m4.large    us-east-1   us-east-1a   3h28m   ip-10-0-129-226.ec2.internal   aws:///us-east-1a/i-010ef6279b4662ced   running
         clustername-8qw5l-worker-us-east-1b-lrdxb   Running        m4.large    us-east-1   us-east-1b   3h28m   ip-10-0-144-248.ec2.internal   aws:///us-east-1b/i-0cb45ac45a166173b   running
         clustername-8qw5l-worker-us-east-1c-pkg26   Running        m4.large    us-east-1   us-east-1c   3h28m   ip-10-0-170-181.ec2.internal   aws:///us-east-1c/i-06861c00007751b0a   running

         1

         The new machine, clustername-8qw5l-master-3 is being created and is ready after the phase changes from Provisioning to Running.

         It might take a few minutes for the new machine to be created. The etcd cluster Operator will automatically sync when the machine or node returns to a healthy state.

      4. Repeat these steps for each lost control plane host that is not the recovery host.

17. Turn off the quorum guard by entering the following command:

    $ oc patch etcd/cluster --type=merge -p '{"spec": {"unsupportedConfigOverrides": {"useUnsupportedUnsafeNonHANonProductionUnstableEtcd": true}}}'

    This command ensures that you can successfully re-create secrets and roll out the static pods.

18. In a separate terminal window within the recovery host, export the recovery kubeconfig file by running the following command:

    $ export KUBECONFIG=/etc/kubernetes/static-pod-resources/kube-apiserver-certs/secrets/node-kubeconfigs/localhost-recovery.kubeconfig

19. Force etcd redeployment.

    In the same terminal window where you exported the recovery kubeconfig file, run the following command:

    $ oc patch etcd cluster -p='{"spec": {"forceRedeploymentReason": "recovery-'"$( date --rfc-3339=ns )"'"}}' --type=merge 1

    1

    The forceRedeploymentReason value must be unique, which is why a timestamp is appended.

    When the etcd cluster Operator performs a redeployment, the existing nodes are started with new pods similar to the initial bootstrap scale up.

20. Turn the quorum guard back on by entering the following command:

    $ oc patch etcd/cluster --type=merge -p '{"spec": {"unsupportedConfigOverrides": null}}'

21. You can verify that the unsupportedConfigOverrides section is removed from the object by entering this command:

    $ oc get etcd/cluster -oyaml

22. Verify all nodes are updated to the latest revision.

    In a terminal that has access to the cluster as a cluster-admin user, run the following command:

    $ oc get etcd -o=jsonpath='{range .items[0].status.conditions[?(@.type=="NodeInstallerProgressing")]}{.reason}{"\n"}{.message}{"\n"}'

    Review the NodeInstallerProgressing status condition for etcd to verify that all nodes are at the latest revision. The output shows AllNodesAtLatestRevision upon successful update:

    AllNodesAtLatestRevision
    3 nodes are at revision 7 1

    1

    In this example, the latest revision number is 7.

    If the output includes multiple revision numbers, such as 2 nodes are at revision 6; 1 nodes are at revision 7, this means that the update is still in progress. Wait a few minutes and try again.

23. After etcd is redeployed, force new rollouts for the control plane. The Kubernetes API server will reinstall itself on the other nodes because the kubelet is connected to API servers using an internal load balancer.

    In a terminal that has access to the cluster as a cluster-admin user, run the following commands.

    1. Force a new rollout for the Kubernetes API server:

       $ oc patch kubeapiserver cluster -p='{"spec": {"forceRedeploymentReason": "recovery-'"$( date --rfc-3339=ns )"'"}}' --type=merge

       Verify all nodes are updated to the latest revision.

       $ oc get kubeapiserver -o=jsonpath='{range .items[0].status.conditions[?(@.type=="NodeInstallerProgressing")]}{.reason}{"\n"}{.message}{"\n"}'

       Review the NodeInstallerProgressing status condition to verify that all nodes are at the latest revision. The output shows AllNodesAtLatestRevision upon successful update:

       AllNodesAtLatestRevision
       3 nodes are at revision 7 1

       1

       In this example, the latest revision number is 7.

       If the output includes multiple revision numbers, such as 2 nodes are at revision 6; 1 nodes are at revision 7, this means that the update is still in progress. Wait a few minutes and try again.

    2. Force a new rollout for the Kubernetes controller manager:

       $ oc patch kubecontrollermanager cluster -p='{"spec": {"forceRedeploymentReason": "recovery-'"$( date --rfc-3339=ns )"'"}}' --type=merge

       Verify all nodes are updated to the latest revision.

       $ oc get kubecontrollermanager -o=jsonpath='{range .items[0].status.conditions[?(@.type=="NodeInstallerProgressing")]}{.reason}{"\n"}{.message}{"\n"}'

       Review the NodeInstallerProgressing status condition to verify that all nodes are at the latest revision. The output shows AllNodesAtLatestRevision upon successful update:

       AllNodesAtLatestRevision
       3 nodes are at revision 7 1

       1

       In this example, the latest revision number is 7.

       If the output includes multiple revision numbers, such as 2 nodes are at revision 6; 1 nodes are at revision 7, this means that the update is still in progress. Wait a few minutes and try again.

    3. Force a new rollout for the Kubernetes scheduler:

       $ oc patch kubescheduler cluster -p='{"spec": {"forceRedeploymentReason": "recovery-'"$( date --rfc-3339=ns )"'"}}' --type=merge

       Verify all nodes are updated to the latest revision.

       $ oc get kubescheduler -o=jsonpath='{range .items[0].status.conditions[?(@.type=="NodeInstallerProgressing")]}{.reason}{"\n"}{.message}{"\n"}'

       Review the NodeInstallerProgressing status condition to verify that all nodes are at the latest revision. The output shows AllNodesAtLatestRevision upon successful update:

       AllNodesAtLatestRevision
       3 nodes are at revision 7 1

       1

       In this example, the latest revision number is 7.

       If the output includes multiple revision numbers, such as 2 nodes are at revision 6; 1 nodes are at revision 7, this means that the update is still in progress. Wait a few minutes and try again.

24. Verify that all control plane hosts have started and joined the cluster.

    In a terminal that has access to the cluster as a cluster-admin user, run the following command:

    $ oc -n openshift-etcd get pods -l k8s-app=etcd

    Example output

    etcd-ip-10-0-143-125.ec2.internal                2/2     Running     0          9h
    etcd-ip-10-0-154-194.ec2.internal                2/2     Running     0          9h
    etcd-ip-10-0-173-171.ec2.internal                2/2     Running     0          9h

1. Create a YAML file with the an object definition similar to the following:

   apiVersion: policy/v1 1
   kind: PodDisruptionBudget
   metadata:
     name: my-pdb
   spec:
     minAvailable: 2  2
     selector:  3
       matchLabels:
         name: my-pod

   1

   PodDisruptionBudget is part of the policy/v1 API group.

   2

   The minimum number of pods that must be available simultaneously. This can be either an integer or a string specifying a percentage, for example, 20%.

   3

   A label query over a set of resources. The result of matchLabels and matchExpressions are logically conjoined. Leave this parameter blank, for example selector {}, to select all pods in the project.

   Or:

   apiVersion: policy/v1 1
   kind: PodDisruptionBudget
   metadata:
     name: my-pdb
   spec:
     maxUnavailable: 25% 2
     selector: 3
       matchLabels:
         name: my-pod

   1

   PodDisruptionBudget is part of the policy/v1 API group.

   2

   The maximum number of pods that can be unavailable simultaneously. This can be either an integer or a string specifying a percentage, for example, 20%.

   3

   A label query over a set of resources. The result of matchLabels and matchExpressions are logically conjoined. Leave this parameter blank, for example selector {}, to select all pods in the project.

2. Run the following command to add the object to project:

   $ oc create -f </path/to/file> -n <project_name>

Procedure

1. Create a YAML file that defines a PodDisruptionBudget object and specify the unhealthy pod eviction policy:

   Example pod-disruption-budget.yaml file

   apiVersion: policy/v1
   kind: PodDisruptionBudget
   metadata:
     name: my-pdb
   spec:
     minAvailable: 2
     selector:
       matchLabels:
         name: my-pod
     unhealthyPodEvictionPolicy: AlwaysAllow 1

   1

   Choose either IfHealthyBudget or AlwaysAllow as the unhealthy pod eviction policy. The default is IfHealthyBudget when the unhealthyPodEvictionPolicy field is empty.

2. Create the PodDisruptionBudget object by running the following command:

   $ oc create -f pod-disruption-budget.yaml

Procedure

1. In the Administrator perspective of the web console, navigate to Workloads → Secrets.

2. In the table on the Secrets page, find the root secret for your cloud provider.

   Platform	Secret name
   AWS	aws-creds
   Azure	azure-credentials
   GCP	gcp-credentials
   RHOSP	openstack-credentials
   RHV	ovirt-credentials
   VMware vSphere	vsphere-creds

3. Click the Options menu in the same row as the secret and select Edit Secret.
4. Record the contents of the Value field or fields. You can use this information to verify that the value is different after updating the credentials.
5. Update the text in the Value field or fields with the new authentication information for your cloud provider, and then click Save.

6. If you are updating the credentials for a vSphere cluster that does not have the vSphere CSI Driver Operator enabled, you must force a rollout of the Kubernetes controller manager to apply the updated credentials.

   Note

   If the vSphere CSI Driver Operator is enabled, this step is not required.

   To apply the updated vSphere credentials, log in to the OpenShift Container Platform CLI as a user with the cluster-admin role and run the following command:

   $ oc patch kubecontrollermanager cluster \
     -p='{"spec": {"forceRedeploymentReason": "recovery-'"$( date )"'"}}' \
     --type=merge

   While the credentials are rolling out, the status of the Kubernetes Controller Manager Operator reports Progressing=true. To view the status, run the following command:

   $ oc get co kube-controller-manager

7. If the CCO for your cluster is configured to use mint mode, delete each component secret that is referenced by the individual CredentialsRequest objects.

   1. Log in to the OpenShift Container Platform CLI as a user with the cluster-admin role.

   2. Get the names and namespaces of all referenced component secrets:

      $ oc -n openshift-cloud-credential-operator get CredentialsRequest \
        -o json | jq -r '.items[] | select (.spec.providerSpec.kind=="<provider_spec>") | .spec.secretRef'

      where <provider_spec> is the corresponding value for your cloud provider:

      • AWS: AWSProviderSpec
      • GCP: GCPProviderSpec

      Partial example output for AWS

      {
        "name": "ebs-cloud-credentials",
        "namespace": "openshift-cluster-csi-drivers"
      }
      {
        "name": "cloud-credential-operator-iam-ro-creds",
        "namespace": "openshift-cloud-credential-operator"
      }

   3. Delete each of the referenced component secrets:

      $ oc delete secret <secret_name> \1
        -n <secret_namespace> 2

      1

      Specify the name of a secret.

      2

      Specify the namespace that contains the secret.

      Example deletion of an AWS secret

      $ oc delete secret ebs-cloud-credentials -n openshift-cluster-csi-drivers

      You do not need to manually delete the credentials from your provider console. Deleting the referenced component secrets will cause the CCO to delete the existing credentials from the platform and create new ones.

1. In the Administrator perspective of the web console, navigate to Workloads → Secrets.
2. Verify that the contents of the Value field or fields have changed.

Procedure

1. In the Administrator perspective of the web console, navigate to Workloads → Secrets.

2. In the table on the Secrets page, find the root secret for your cloud provider.

   Platform	Secret name
   AWS	aws-creds
   GCP	gcp-credentials

3. Click the Options menu in the same row as the secret and select Delete Secret.

Procedure

1. Ensure that the kubeconfig file for the cluster and the installation program that you used to install the cluster are on the RHEL 8 machine. One way to accomplish this is to use the same machine that you used to install the cluster.
2. Configure the machine to access all of the RHEL hosts that you plan to use as compute machines. You can use any method that your company allows, including a bastion with an SSH proxy or a VPN.

3. Configure a user on the machine that you run the playbook on that has SSH access to all of the RHEL hosts.

   Important

   If you use SSH key-based authentication, you must manage the key with an SSH agent.

4. If you have not already done so, register the machine with RHSM and attach a pool with an OpenShift subscription to it:

   1. Register the machine with RHSM:

      # subscription-manager register --username=<user_name> --password=<password>

   2. Pull the latest subscription data from RHSM:

      # subscription-manager refresh

   3. List the available subscriptions:

      # subscription-manager list --available --matches '*OpenShift*'

   4. In the output for the previous command, find the pool ID for an OpenShift Container Platform subscription and attach it:

      # subscription-manager attach --pool=<pool_id>

5. Enable the repositories required by OpenShift Container Platform 4.13:

   # subscription-manager repos \
       --enable="rhel-8-for-x86_64-baseos-rpms" \
       --enable="rhel-8-for-x86_64-appstream-rpms" \
       --enable="rhocp-4.13-for-rhel-8-x86_64-rpms"

6. Install the required packages, including openshift-ansible:

   # yum install openshift-ansible openshift-clients jq

   The openshift-ansible package provides installation program utilities and pulls in other packages that you require to add a RHEL compute node to your cluster, such as Ansible, playbooks, and related configuration files. The openshift-clients provides the oc CLI, and the jq package improves the display of JSON output on your command line.

1. On each host, register with RHSM:

   # subscription-manager register --username=<user_name> --password=<password>

2. Pull the latest subscription data from RHSM:

   # subscription-manager refresh

3. List the available subscriptions:

   # subscription-manager list --available --matches '*OpenShift*'

4. In the output for the previous command, find the pool ID for an OpenShift Container Platform subscription and attach it:

   # subscription-manager attach --pool=<pool_id>

5. Disable all yum repositories:

   1. Disable all the enabled RHSM repositories:

      # subscription-manager repos --disable="*"

   2. List the remaining yum repositories and note their names under repo id, if any:

      # yum repolist

   3. Use yum-config-manager to disable the remaining yum repositories:

      # yum-config-manager --disable <repo_id>

      Alternatively, disable all repositories:

      # yum-config-manager --disable \*

      Note that this might take a few minutes if you have a large number of available repositories

6. Enable only the repositories required by OpenShift Container Platform 4.13:

   # subscription-manager repos \
       --enable="rhel-8-for-x86_64-baseos-rpms" \
       --enable="rhel-8-for-x86_64-appstream-rpms" \
       --enable="rhocp-4.13-for-rhel-8-x86_64-rpms" \
       --enable="fast-datapath-for-rhel-8-x86_64-rpms"

7. Stop and disable firewalld on the host:

   # systemctl disable --now firewalld.service

   Note

   You must not enable firewalld later. If you do, you cannot access OpenShift Container Platform logs on the worker.

1. Create an Ansible inventory file that is named /<path>/inventory/hosts that defines your compute machine hosts and required variables:

   [all:vars]
   ansible_user=root 1
   #ansible_become=True 2
   
   openshift_kubeconfig_path="~/.kube/config" 3
   
   [new_workers] 4
   mycluster-rhel8-0.example.com
   mycluster-rhel8-1.example.com

   1

   Specify the user name that runs the Ansible tasks on the remote compute machines.

   2

   If you do not specify root for the ansible_user, you must set ansible_become to True and assign the user sudo permissions.

   3

   Specify the path and file name of the kubeconfig file for your cluster.

   4

   List each RHEL machine to add to your cluster. You must provide the fully-qualified domain name for each host. This name is the hostname that the cluster uses to access the machine, so set the correct public or private name to access the machine.

2. Navigate to the Ansible playbook directory:

   $ cd /usr/share/ansible/openshift-ansible

3. Run the playbook:

   $ ansible-playbook -i /<path>/inventory/hosts playbooks/scaleup.yml 1

   1

   For <path>, specify the path to the Ansible inventory file that you created.

Procedure

1. View the list of machines and record the node names of the RHCOS compute machines:

   $ oc get nodes -o wide

2. For each RHCOS compute machine, delete the node:

   1. Mark the node as unschedulable by running the oc adm cordon command:

      $ oc adm cordon <node_name> 1

      1

      Specify the node name of one of the RHCOS compute machines.

   2. Drain all the pods from the node:

      $ oc adm drain <node_name> --force --delete-emptydir-data --ignore-daemonsets 1

      1

      Specify the node name of the RHCOS compute machine that you isolated.

   3. Delete the node:

      $ oc delete nodes <node_name> 1

      1

      Specify the node name of the RHCOS compute machine that you drained.

3. Review the list of compute machines to ensure that only the RHEL nodes remain:

   $ oc get nodes -o wide

4. Remove the RHCOS machines from the load balancer for your cluster’s compute machines. You can delete the virtual machines or reimage the physical hardware for the RHCOS compute machines.

Procedure

1. Extract the Ignition config file from the cluster by running the following command:

   $ oc extract -n openshift-machine-api secret/worker-user-data-managed --keys=userData --to=- > worker.ign

2. Upload the worker.ign Ignition config file you exported from your cluster to your HTTP server. Note the URLs of these files.

3. You can validate that the ignition files are available on the URLs. The following example gets the Ignition config files for the compute node:

   $ curl -k http://<HTTP_server>/worker.ign

4. You can access the ISO image for booting your new machine by running to following command:

   RHCOS_VHD_ORIGIN_URL=$(oc -n openshift-machine-config-operator get configmap/coreos-bootimages -o jsonpath='{.data.stream}' | jq -r '.architectures.<architecture>.artifacts.metal.formats.iso.disk.location')

5. Use the ISO file to install RHCOS on more compute machines. Use the same method that you used when you created machines before you installed the cluster:

   • Burn the ISO image to a disk and boot it directly.
   • Use ISO redirection with a LOM interface.

6. Boot the RHCOS ISO image without specifying any options, or interrupting the live boot sequence. Wait for the installer to boot into a shell prompt in the RHCOS live environment.

   Note

   You can interrupt the RHCOS installation boot process to add kernel arguments. However, for this ISO procedure you must use the coreos-installer command as outlined in the following steps, instead of adding kernel arguments.

7. Run the coreos-installer command and specify the options that meet your installation requirements. At a minimum, you must specify the URL that points to the Ignition config file for the node type, and the device that you are installing to:

   $ sudo coreos-installer install --ignition-url=http://<HTTP_server>/<node_type>.ign <device> --ignition-hash=sha512-<digest> 12

   1

   You must run the coreos-installer command by using sudo, because the core user does not have the required root privileges to perform the installation.

   2

   The --ignition-hash option is required when the Ignition config file is obtained through an HTTP URL to validate the authenticity of the Ignition config file on the cluster node. <digest> is the Ignition config file SHA512 digest obtained in a preceding step.

   Note

   If you want to provide your Ignition config files through an HTTPS server that uses TLS, you can add the internal certificate authority (CA) to the system trust store before running coreos-installer.

   The following example initializes a bootstrap node installation to the /dev/sda device. The Ignition config file for the bootstrap node is obtained from an HTTP web server with the IP address 192.168.1.2:

   $ sudo coreos-installer install --ignition-url=http://192.168.1.2:80/installation_directory/bootstrap.ign /dev/sda --ignition-hash=sha512-a5a2d43879223273c9b60af66b44202a1d1248fc01cf156c46d4a79f552b6bad47bc8cc78ddf0116e80c59d2ea9e32ba53bc807afbca581aa059311def2c3e3b

8. Monitor the progress of the RHCOS installation on the console of the machine.

   Important

   Ensure that the installation is successful on each node before commencing with the OpenShift Container Platform installation. Observing the installation process can also help to determine the cause of RHCOS installation issues that might arise.

9. Continue to create more compute machines for your cluster.

Procedure

1. Confirm that your PXE or iPXE installation for the RHCOS images is correct.

   • For PXE:

     DEFAULT pxeboot
     TIMEOUT 20
     PROMPT 0
     LABEL pxeboot
         KERNEL http://<HTTP_server>/rhcos-<version>-live-kernel-<architecture> 1
         APPEND initrd=http://<HTTP_server>/rhcos-<version>-live-initramfs.<architecture>.img coreos.inst.install_dev=/dev/sda coreos.inst.ignition_url=http://<HTTP_server>/worker.ign coreos.live.rootfs_url=http://<HTTP_server>/rhcos-<version>-live-rootfs.<architecture>.img 2

     1

     Specify the location of the live kernel file that you uploaded to your HTTP server.

     2

     Specify locations of the RHCOS files that you uploaded to your HTTP server. The initrd parameter value is the location of the live initramfs file, the coreos.inst.ignition_url parameter value is the location of the worker Ignition config file, and the coreos.live.rootfs_url parameter value is the location of the live rootfs file. The coreos.inst.ignition_url and coreos.live.rootfs_url parameters only support HTTP and HTTPS.

     Note

     This configuration does not enable serial console access on machines with a graphical console. To configure a different console, add one or more console= arguments to the APPEND line. For example, add console=tty0 console=ttyS0 to set the first PC serial port as the primary console and the graphical console as a secondary console. For more information, see How does one set up a serial terminal and/or console in Red Hat Enterprise Linux?.

   • For iPXE (x86_64 + aarch64):

     kernel http://<HTTP_server>/rhcos-<version>-live-kernel-<architecture> initrd=main coreos.live.rootfs_url=http://<HTTP_server>/rhcos-<version>-live-rootfs.<architecture>.img coreos.inst.install_dev=/dev/sda coreos.inst.ignition_url=http://<HTTP_server>/worker.ign 1 2
     initrd --name main http://<HTTP_server>/rhcos-<version>-live-initramfs.<architecture>.img 3
     boot

     1

     Specify the locations of the RHCOS files that you uploaded to your HTTP server. The kernel parameter value is the location of the kernel file, the initrd=main argument is needed for booting on UEFI systems, the coreos.live.rootfs_url parameter value is the location of the rootfs file, and the coreos.inst.ignition_url parameter value is the location of the worker Ignition config file.

     2

     If you use multiple NICs, specify a single interface in the ip option. For example, to use DHCP on a NIC that is named eno1, set ip=eno1:dhcp.

     3

     Specify the location of the initramfs file that you uploaded to your HTTP server.

     Note

     This configuration does not enable serial console access on machines with a graphical console To configure a different console, add one or more console= arguments to the kernel line. For example, add console=tty0 console=ttyS0 to set the first PC serial port as the primary console and the graphical console as a secondary console. For more information, see How does one set up a serial terminal and/or console in Red Hat Enterprise Linux? and "Enabling the serial console for PXE and ISO installation" in the "Advanced RHCOS installation configuration" section.

     Note

     To network boot the CoreOS kernel on aarch64 architecture, you need to use a version of iPXE build with the IMAGE_GZIP option enabled. See IMAGE_GZIP option in iPXE.

   • For PXE (with UEFI and GRUB as second stage) on aarch64:

     menuentry 'Install CoreOS' {
         linux rhcos-<version>-live-kernel-<architecture>  coreos.live.rootfs_url=http://<HTTP_server>/rhcos-<version>-live-rootfs.<architecture>.img coreos.inst.install_dev=/dev/sda coreos.inst.ignition_url=http://<HTTP_server>/worker.ign 1 2
         initrd rhcos-<version>-live-initramfs.<architecture>.img 3
     }

     1

     Specify the locations of the RHCOS files that you uploaded to your HTTP/TFTP server. The kernel parameter value is the location of the kernel file on your TFTP server. The coreos.live.rootfs_url parameter value is the location of the rootfs file, and the coreos.inst.ignition_url parameter value is the location of the worker Ignition config file on your HTTP Server.

     2

     If you use multiple NICs, specify a single interface in the ip option. For example, to use DHCP on a NIC that is named eno1, set ip=eno1:dhcp.

     3

     Specify the location of the initramfs file that you uploaded to your TFTP server.

2. Use the PXE or iPXE infrastructure to create the required compute machines for your cluster.