As a cluster administrator, you can rollback to the OpenShift SDN cluster default Container Network Interface (CNI) provider from the OVN-Kubernetes default CNI network provider if the migration to OVN-Kubernetes unsuccessful.

Rolling back the default CNI network provider to OpenShift SDN

As a cluster administrator, you can rollback your cluster to the OpenShift SDN default Container Network Interface (CNI) network provider. During the rollback, you must reboot every node in your cluster.

Only rollback to OpenShift SDN if the migration to OVN-Kubernetes is unsuccessful.

Prerequisites
  • Install the OpenShift Command-line Interface (CLI), commonly known as oc.

  • Access to the cluster as a user with the cluster-admin role.

  • A cluster installed on bare metal infrastructure configured with the OVN-Kubernetes default CNI network provider.

    1. To enable the migration, set an annotation on the Cluster Network Operator configuration object by entering the following command:

      $ oc annotate Network.operator.openshift.io cluster \
        'networkoperator.openshift.io/network-migration'=""
    2. To change the default CNI network provider, enter the following command:

      $ oc patch Network.config.openshift.io cluster \
        --type='merge' --patch '{ "spec": { "networkType": "OpenShiftSDN" } }'
    3. Optional: Use the backup of the cluster network configuration that you created before the migration to restore any customizations to the network configuration that you might have made. To restore the customizations, enter the following command to edit the Cluster Network Operator configuration:

      $ oc edit Network.config.openshift.io cluster
    4. To confirm that the migration disabled the OVN-Kubernetes default CNI network provider, enter the following command. It might take several moments for all the OVN-Kubernetes Pods to stop.

      $ oc get pod -n openshift-ovn-kubernetes --watch
    5. To complete the rollback, reboot each node in your cluster. For example, you could use a bash script similar to the following. The script assumes that you can connect to each host by using ssh and that you have configured sudo to not prompt for a password.

      #!/bin/bash
      
      for ip in $(oc get nodes  -o jsonpath='{.items[*].status.addresses[?(@.type=="InternalIP")].address}')
      do
         echo "reboot node $ip"
         ssh -o StrictHostKeyChecking=no core@$ip sudo shutdown -r -t 3
      done
    6. After the nodes in your cluster have rebooted, enter the following command to confirm that the default CNI network provider is OpenShift SDN. The value of status.networkType must be OpenShiftSDN.

      $ oc get network.config/cluster -o jsonpath='{.status.networkType}{"\n"}'
    7. To confirm that the OpenShift SDN Pods are in the READY state, enter the following command:

      $ oc get pod -n openshift-sdn --watch
    8. To remove the migration annotation from the Cluster Network Operator configuration object, enter the following command:

      $ oc annotate Network.operator.openshift.io cluster \
        networkoperator.openshift.io/network-migration-
    9. To remove the OVN-Kubernetes network provider namespace, enter the following command:

      $ oc delete namespace openshift-ovn-kubernetes