New to KubeDB? Please start here.
Restart Pgpool
KubeDB supports restarting the Pgpool via a PgpoolOpsRequest. 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/pgpool folder in GitHub repository kubedb/docs.
Prepare Postgres
Prepare a KubeDB Postgres cluster using this tutorial, or you can use any externally managed postgres but in that case you need to create an appbinding yourself. In this tutorial we will use 3 node Postgres cluster named ha-postgres.
Deploy Pgpool
In this section, we are going to deploy a Pgpool using KubeDB.
apiVersion: kubedb.com/v1alpha2
kind: Pgpool
metadata:
name: pgpool
namespace: demo
spec:
version: "4.4.5"
replicas: 1
postgresRef:
name: ha-postgres
namespace: demo
deletionPolicy: WipeOut
Let’s create the Pgpool CR we have shown above,
$ kubectl create -f https://github.com/kubedb/docs/raw/v2024.12.18/docs/examples/pgpool/restart/pgpool.yaml
pgpool.kubedb.com/pgpool created
Apply Restart opsRequest
apiVersion: ops.kubedb.com/v1alpha1
kind: PgpoolOpsRequest
metadata:
name: restart-pgpool
namespace: demo
spec:
type: Restart
databaseRef:
name: pgpool
timeout: 3m
apply: Always
spec.typespecifies the Type of the ops Requestspec.databaseRefholds the name of the Pgpool. The pgpool should be available in the same namespace as the opsRequest- The meaning of
spec.timeout&spec.applyfields will be found here
Let’s create the PgpoolOpsRequest CR we have shown above,
$ kubectl create -f https://github.com/kubedb/docs/raw/v2024.12.18/docs/examples/pgpool/restart/ops.yaml
pgpoolopsrequest.ops.kubedb.com/restart-pgpool created
Now the Ops-manager operator will restart the pods one by one.
$ kubectl get ppops -n demo
NAME TYPE STATUS AGE
restart-pgpool Restart Successful 79s
$ kubectl get ppops -n demo -oyaml restart-pgpool
apiVersion: ops.kubedb.com/v1alpha1
kind: PgpoolOpsRequest
metadata:
annotations:
kubectl.kubernetes.io/last-applied-configuration: |
{"apiVersion":"ops.kubedb.com/v1alpha1","kind":"PgpoolOpsRequest","metadata":{"annotations":{},"name":"restart-pgpool","namespace":"demo"},"spec":{"apply":"Always","databaseRef":{"name":"pgpool"},"timeout":"3m","type":"Restart"}}
creationTimestamp: "2024-07-18T06:49:50Z"
generation: 1
name: restart-pgpool
namespace: demo
resourceVersion: "94394"
uid: 8d3387fc-0c21-4e14-8bed-857a7cdf5423
spec:
apply: Always
databaseRef:
name: pgpool
timeout: 3m
type: Restart
status:
conditions:
- lastTransitionTime: "2024-07-18T06:49:50Z"
message: Pgpool ops-request has started to restart pgpool nodes
observedGeneration: 1
reason: Restart
status: "True"
type: Restart
- lastTransitionTime: "2024-07-18T06:49:53Z"
message: Successfully paused database
observedGeneration: 1
reason: DatabasePauseSucceeded
status: "True"
type: DatabasePauseSucceeded
- lastTransitionTime: "2024-07-18T06:50:38Z"
message: Successfully Restarted Pgpool nodes
observedGeneration: 1
reason: RestartNodes
status: "True"
type: RestartNodes
- lastTransitionTime: "2024-07-18T06:49:58Z"
message: get pod; ConditionStatus:True; PodName:pgpool-0
observedGeneration: 1
status: "True"
type: GetPod--pgpool-0
- lastTransitionTime: "2024-07-18T06:49:58Z"
message: evict pod; ConditionStatus:True; PodName:pgpool-0
observedGeneration: 1
status: "True"
type: EvictPod--pgpool-0
- lastTransitionTime: "2024-07-18T06:50:33Z"
message: check pod running; ConditionStatus:True; PodName:pgpool-0
observedGeneration: 1
status: "True"
type: CheckPodRunning--pgpool-0
- lastTransitionTime: "2024-07-18T06:50:38Z"
message: Controller has successfully restart the Pgpool replicas
observedGeneration: 1
reason: Successful
status: "True"
type: Successful
observedGeneration: 1
phase: Successful
Cleaning up
To clean up the Kubernetes resources created by this tutorial, run:
kubectl delete pgpoolopsrequest -n demo restart-pgpool
kubectl delete pgpool -n demo pgpool
kubectl delete ns demo
Next Steps
- Detail concepts of Pgpool object.
- Monitor your Pgpool database with KubeDB using out-of-the-box Prometheus operator.
- Monitor your Pgpool database with KubeDB using out-of-the-box builtin-Prometheus.
- Detail concepts of Pgpool object.
- Want to hack on KubeDB? Check our contribution guidelines.