Chapter 8. AWS Local Zone or Wavelength Zone tasks

Procedure

1. To obtain the current MTU for the cluster network, enter the following command:

   $ oc describe network.config cluster

   Example output

   ...
   Status:
     Cluster Network:
       Cidr:               10.217.0.0/22
       Host Prefix:        23
     Cluster Network MTU:  1400
     Network Type:         OVNKubernetes
     Service Network:
       10.217.4.0/23
   ...

2. To begin the MTU migration, specify the migration configuration by entering the following command. The Machine Config Operator performs a rolling reboot of the nodes in the cluster in preparation for the MTU change.

   $ oc patch Network.operator.openshift.io cluster --type=merge --patch \
     '{"spec": { "migration": { "mtu": { "network": { "from": <overlay_from>, "to": <overlay_to> } , "machine": { "to" : <machine_to> } } } } }'

   where:

   <overlay_from>

   Specifies the current cluster network MTU value.

   <overlay_to>

   Specifies the target MTU for the cluster network. This value is set relative to the value of <machine_to>. For OVN-Kubernetes, this value must be 100 less than the value of <machine_to>.

   <machine_to>

   Specifies the MTU for the primary network interface on the underlying host network.

   Example that increases the cluster MTU

   $ oc patch Network.operator.openshift.io cluster --type=merge --patch \
     '{"spec": { "migration": { "mtu": { "network": { "from": 1400, "to": 9000 } , "machine": { "to" : 9100} } } } }'

3. As the Machine Config Operator updates machines in each machine config pool, it reboots each node one by one. You must wait until all the nodes are updated. Check the machine config pool status by entering the following command:

   $ oc get machineconfigpools

   A successfully updated node has the following status: UPDATED=true, UPDATING=false, DEGRADED=false.

   Note

   By default, the Machine Config Operator updates one machine per pool at a time, causing the total time the migration takes to increase with the size of the cluster.

4. Confirm the status of the new machine configuration on the hosts:

   1. To list the machine configuration state and the name of the applied machine configuration, enter the following command:

      $ oc describe node | egrep "hostname|machineconfig"

      Example output

      kubernetes.io/hostname=master-0
      machineconfiguration.openshift.io/currentConfig: rendered-master-c53e221d9d24e1c8bb6ee89dd3d8ad7b
      machineconfiguration.openshift.io/desiredConfig: rendered-master-c53e221d9d24e1c8bb6ee89dd3d8ad7b
      machineconfiguration.openshift.io/reason:
      machineconfiguration.openshift.io/state: Done

   2. Verify that the following statements are true:

      • The value of machineconfiguration.openshift.io/state field is Done.
      • The value of the machineconfiguration.openshift.io/currentConfig field is equal to the value of the machineconfiguration.openshift.io/desiredConfig field.

   3. To confirm that the machine config is correct, enter the following command:

      $ oc get machineconfig <config_name> -o yaml | grep ExecStart

      where <config_name> is the name of the machine config from the machineconfiguration.openshift.io/currentConfig field.

      The machine config must include the following update to the systemd configuration:

      ExecStart=/usr/local/bin/mtu-migration.sh

5. To finalize the MTU migration, enter the following command for the OVN-Kubernetes network plugin:

   $ oc patch Network.operator.openshift.io cluster --type=merge --patch \
     '{"spec": { "migration": null, "defaultNetwork":{ "ovnKubernetesConfig": { "mtu": <mtu> }}}}'

   where:

   <mtu>

   Specifies the new cluster network MTU that you specified with <overlay_to>.

6. After finalizing the MTU migration, each machine config pool node is rebooted one by one. You must wait until all the nodes are updated. Check the machine config pool status by entering the following command:

   $ oc get machineconfigpools

   A successfully updated node has the following status: UPDATED=true, UPDATING=false, DEGRADED=false.

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