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Version: release-0.9

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.

The value of instanceName decides whether a new primary instance is specified for the switchover.

  • Switchover with no specified primary instance

    kubectl apply -f -<<EOF
    apiVersion: apps.kubeblocks.io/v1alpha1
    kind: OpsRequest
    metadata:
      name: mycluster-switchover-jhkgl
      namespace: demo
    spec:
      clusterRef: mycluster
      type: Switchover
      switchover:
      - componentName: mongodb
        instanceName: '*'
    >>

  • Switchover with a specified new primary instance

    kubectl apply -f -<<EOF
    apiVersion: apps.kubeblocks.io/v1alpha1
    kind: OpsRequest
    metadata:
      name: mycluster-switchover-jhkgl
      namespace: demo
    spec:
      clusterRef: mycluster
      type: Switchover
      switchover:
      - componentName: mongodb
        instanceName: 'mycluster-mongodb-2'
    >>

Verify the switchover​

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

kubectl get pods -n demo

Handle an exception​

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