Switch over a MongoDB cluster

You can initiate a switchover for a MongoDB ReplicaSet. Then KubeBlocks modifies the instance roles.

Before you start

• Make sure the cluster is running normally.

• Check whether the following role probe parameters exist to verify whether the role probe is enabled.

  kubectl get cd mongodb -o yaml
  >
  probes:
    roleProbe:
      failureThreshold: 3
      periodSeconds: 2
      timeoutSeconds: 2

Initiate the switchover

You can switch over a secondary of a MongoDB ReplicaSet to the primary role, and the former primary instance to a secondary.

• Switchover with no primary instance specified

  kbcli cluster promote mycluster

• Switchover with a specified new primary instance

  kbcli cluster promote mycluster --instance='mycluster-mongodb-2'

• If there are multiple components, you can use --components to specify a component.

  kbcli cluster promote mycluster --instance='mycluster-mongodb-2' --components='mongodb'

Verify the switchover

Check the instance status to verify whether the switchover is performed successfully.

kbcli cluster list-instances

Handle an exception

If an error occurs, refer to Handle an exaception to troubleshoot the operation.