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Restart Postgres
KubeDB supports restarting the Postgres database via a PostgresOpsRequest. Restarting is useful if some pods are got stuck in some phase, or they are not working correctly. This tutorial will show you how to use that.
Before You Begin
At first, you need to have a Kubernetes cluster, and the kubectl command-line tool must be configured to communicate with your cluster. If you do not already have a cluster, you can create one by using kind.
Now, install KubeDB cli on your workstation and KubeDB operator in your cluster following the steps here.
To keep things isolated, this tutorial uses a separate namespace called
demothroughout this tutorial.
$ kubectl create ns demo
namespace/demo created
Note: YAML files used in this tutorial are stored in docs/examples/postgres folder in GitHub repository kubedb/docs.
Deploy Postgres
In this section, we are going to deploy a Postgres database using KubeDB.
apiVersion: kubedb.com/v1
kind: Postgres
metadata:
name: ha-postgres
namespace: demo
spec:
replicas: 3
storageType: Durable
deletionPolicy: WipeOut
storage:
storageClassName: "standard"
accessModes:
- ReadWriteOnce
resources:
requests:
storage: 1Gi
version: "13.13"
Let’s create the Postgres CR we have shown above,
$ kubectl create -f https://github.com/kubedb/docs/raw/v2024.9.30/docs/examples/postgres/restart/postgres.yaml
postgres.kubedb.com/ha-postgres created
Apply Restart opsRequest
apiVersion: ops.kubedb.com/v1alpha1
kind: PostgresOpsRequest
metadata:
name: restart
namespace: demo
spec:
type: Restart
databaseRef:
name: ha-postgres
timeout: 3m
apply: Always
spec.typespecifies the Type of the ops Requestspec.databaseRefholds the name of the Postgres database. The db should be available in the same namespace as the opsRequest- The meaning of
spec.timeout&spec.applyfields can be found here
Note: The method of restarting the standalone & cluster mode db is exactly same as above. All you need, is to specify the corresponding Postgres name in
spec.databaseRef.namesection.
Let’s create the PostgresOpsRequest CR we have shown above,
$ kubectl create -f https://github.com/kubedb/docs/raw/v2024.9.30/docs/examples/postgres/restart/ops.yaml
postgresopsrequest.ops.kubedb.com/restart created
Now the Ops-manager operator will first restart the general secondary pods and lastly will restart the Primary pod of the database.
Note: This will not restart the arbiter pod if you have one. Arbiter pod doesn’t have any data related to your database. So you can ignore restarting this pod because no restart is necessary for arbiter pod but if you want so, just kubectl delete the arbiter pod (dbName-arbiter-0) in order to restart it.
$ kubectl get pgops -n demo restart
NAME TYPE STATUS AGE
restart Restart Successful 3m25s
$ kubectl get pgops -n demo restart -oyaml
apiVersion: ops.kubedb.com/v1alpha1
kind: PostgresOpsRequest
metadata:
annotations:
kubectl.kubernetes.io/last-applied-configuration: |
{"apiVersion":"ops.kubedb.com/v1alpha1","kind":"PostgresOpsRequest","metadata":{"annotations":{},"name":"restart","namespace":"demo"},"spec":{"apply":"Always","databaseRef":{"name":"ha-postgres"},"timeout":"3m","type":"Restart"}}
creationTimestamp: "2024-08-16T10:24:22Z"
generation: 1
name: restart
namespace: demo
resourceVersion: "568540"
uid: dc829c3c-81fb-4da3-b83d-a2c2f09fa73b
spec:
apply: Always
databaseRef:
name: ha-postgres
timeout: 3m
type: Restart
status:
conditions:
- lastTransitionTime: "2024-08-16T10:24:22Z"
message: Postgres ops request is restarting nodes
observedGeneration: 1
reason: Restart
status: "True"
type: Restart
- lastTransitionTime: "2024-08-16T10:24:22Z"
message: successfully resumed pg-coordinator
observedGeneration: 1
reason: ResumePGCoordinator
status: "True"
type: ResumePGCoordinator
- lastTransitionTime: "2024-08-16T10:26:11Z"
message: Successfully restarted all nodes
observedGeneration: 1
reason: RestartNodes
status: "True"
type: RestartNodes
- lastTransitionTime: "2024-08-16T10:24:31Z"
message: evict pod; ConditionStatus:True
observedGeneration: 1
status: "True"
type: EvictPod
- lastTransitionTime: "2024-08-16T10:24:31Z"
message: check pod ready; ConditionStatus:False; PodName:ha-postgres-1
observedGeneration: 1
status: "False"
type: CheckPodReady--ha-postgres-1
- lastTransitionTime: "2024-08-16T10:25:05Z"
message: check pod ready; ConditionStatus:True
observedGeneration: 1
status: "True"
type: CheckPodReady
- lastTransitionTime: "2024-08-16T10:25:05Z"
message: check replica func; ConditionStatus:False; PodName:ha-postgres-1
observedGeneration: 1
status: "False"
type: CheckReplicaFunc--ha-postgres-1
- lastTransitionTime: "2024-08-16T10:25:10Z"
message: check replica func; ConditionStatus:True
observedGeneration: 1
status: "True"
type: CheckReplicaFunc
- lastTransitionTime: "2024-08-16T10:25:10Z"
message: get primary; ConditionStatus:True
observedGeneration: 1
status: "True"
type: GetPrimary
- lastTransitionTime: "2024-08-16T10:25:11Z"
message: transfer leader; ConditionStatus:True
observedGeneration: 1
status: "True"
type: TransferLeader
- lastTransitionTime: "2024-08-16T10:25:16Z"
message: transfer leader for failover; ConditionStatus:True
observedGeneration: 1
status: "True"
type: TransferLeaderForFailover
- lastTransitionTime: "2024-08-16T10:25:16Z"
message: check is master; ConditionStatus:True
observedGeneration: 1
status: "True"
type: CheckIsMaster
- lastTransitionTime: "2024-08-16T10:25:16Z"
message: failover is done successfully
observedGeneration: 1
reason: FailoverDone
status: "True"
type: FailoverDone
- lastTransitionTime: "2024-08-16T10:25:16Z"
message: update ops request; ConditionStatus:True
observedGeneration: 1
status: "True"
type: UpdateOpsRequest
- lastTransitionTime: "2024-08-16T10:25:16Z"
message: check pod ready; ConditionStatus:False; PodName:ha-postgres-0
observedGeneration: 1
status: "False"
type: CheckPodReady--ha-postgres-0
- lastTransitionTime: "2024-08-16T10:26:00Z"
message: check replica func; ConditionStatus:False; PodName:ha-postgres-0
observedGeneration: 1
status: "False"
type: CheckReplicaFunc--ha-postgres-0
- lastTransitionTime: "2024-08-16T10:26:11Z"
message: Successfully completed the modification process.
observedGeneration: 1
reason: Successful
status: "True"
type: Successful
observedGeneration: 1
phase: Successful
Cleaning up
To cleanup the Kubernetes resources created by this tutorial, run:
kubectl delete postgresopsrequest -n demo restart
kubectl delete postgres -n demo ha-postgres
kubectl delete ns demo
Next Steps
- Learn about backup and restore PostgreSQL database using Stash.
- Learn about initializing PostgreSQL with Script.
- Learn about custom PostgresVersions.
- Want to setup PostgreSQL cluster? Check how to configure Highly Available PostgreSQL Cluster
- Monitor your PostgreSQL database with KubeDB using built-in Prometheus.
- Monitor your PostgreSQL database with KubeDB using Prometheus operator.
- Detail concepts of Postgres object.
- Use private Docker registry to deploy PostgreSQL with KubeDB.
- Want to hack on KubeDB? Check our contribution guidelines.