Switch over a PostgreSQL cluster

You can initiate a switchover for a PostgreSQL Replication Cluster. 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 postgresql -o yaml
  >
   probes:
     roleProbe:
       failureThreshold: 2
       periodSeconds: 1
       timeoutSeconds: 1

Initiate the switchover

You can switch over a secondary Pod of a PostgreSQL PrimarySecondary cluster to the primary one, 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
    namespace: demo
  spec:
    clusterName: mycluster
    type: Switchover
    switchover:
    - componentName: postgresql
      instanceName: '*'
  >>

• Switchover with a specified new primary instance

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

Verify the switchover

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

kubectl get cluster mycluster -n demo

kubectl -n demo get po -L kubeblocks.io/role 

Handle an exception

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