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update version of Pgpool

This guide will show you how to use KubeDB Ops-manager operator to update the version of Pgpool.

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.

  • Install KubeDB Provisioner and Ops-manager operator in your cluster following the steps here.

  • You should be familiar with the following KubeDB concepts:

To keep everything isolated, we are going to use a separate namespace called demo throughout this tutorial.

$ kubectl create ns demo
namespace/demo created

Note: YAML files used in this tutorial are stored in docs/examples/pgpool directory of kubedb/docs repository.

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.

Prepare Pgpool

Now, we are going to deploy a Pgpool =with version 4.4.5.

Deploy Pgpool:

In this section, we are going to deploy a Pgpool. Then, in the next section we will update the version using PgpoolOpsRequest CRD. Below is the YAML of the Pgpool CR that we are going to create,

apiVersion: kubedb.com/v1alpha2
kind: Pgpool
metadata:
  name: pp-update
  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/v2024.11.18/docs/examples/pgpool/update-version/pp-update.yaml
pgpool.kubedb.com/pp-update created

Now, wait until pp-update created has status Ready. i.e,

$ kubectl get pp -n demo
 NAME        TYPE                  VERSION   STATUS   AGE
 pp-update   kubedb.com/v1alpha2   4.4.5     Ready    26s

We are now ready to apply the PgpoolOpsRequest CR to update this Pgpool.

update Pgpool Version

Here, we are going to update Pgpool from 4.4.5 to 4.5.0.

Create PgpoolOpsRequest:

In order to update the Pgpool, we have to create a PgpoolOpsRequest CR with your desired version that is supported by KubeDB. Below is the YAML of the PgpoolOpsRequest CR that we are going to create,

apiVersion: ops.kubedb.com/v1alpha1
kind: PgpoolOpsRequest
metadata:
  name: pgpool-version-update
  namespace: demo
spec:
  type: UpdateVersion
  databaseRef:
    name: pp-update
  updateVersion:
    targetVersion: 4.5.0

Here,

  • spec.databaseRef.name specifies that we are performing operation on pp-update Pgpool.
  • spec.type specifies that we are going to perform UpdateVersion on our Pgpool.
  • spec.updateVersion.targetVersion specifies the expected version of the Pgpool 4.5.0.

Let’s create the PgpoolOpsRequest CR we have shown above,

$ kubectl apply -f https://github.com/kubedb/docs/raw/v2024.11.18/docs/examples/pgpool/update-version/ppops-update.yaml
pgpoolopsrequest.ops.kubedb.com/pgpool-version-update created

Verify Pgpool version updated successfully :

If everything goes well, KubeDB Ops-manager operator will update the image of Pgpool object and related PetSets and Pods.

Let’s wait for PgpoolOpsRequest to be Successful. Run the following command to watch PgpoolOpsRequest CR,

$ watch kubectl get pgpoolopsrequest -n demo
Every 2.0s: kubectl get pgpoolopsrequest -n demo
NAME                      TYPE                STATUS       AGE
pgpool-version-update     UpdateVersion       Successful   93s

We can see from the above output that the PgpoolOpsRequest has succeeded. If we describe the PgpoolOpsRequest we will get an overview of the steps that were followed to update the Pgpool.

$ kubectl describe pgpoolopsrequest -n demo pgpool-version-update
Name:         pgpool-version-update
Namespace:    demo
Labels:       <none>
Annotations:  <none>
API Version:  ops.kubedb.com/v1alpha1
Kind:         PgpoolOpsRequest
Metadata:
  Creation Timestamp:  2024-07-17T06:31:58Z
  Generation:          1
  Resource Version:    51165
  UID:                 1409aec6-3a25-4b2b-90fe-02e5d8b1e8c1
Spec:
  Apply:  IfReady
  Database Ref:
    Name:  pp-update
  Type:    UpdateVersion
  Update Version:
    Target Version:  4.5.0
Status:
  Conditions:
    Last Transition Time:  2024-07-17T06:31:58Z
    Message:               Pgpool ops-request has started to update version
    Observed Generation:   1
    Reason:                UpdateVersion
    Status:                True
    Type:                  UpdateVersion
    Last Transition Time:  2024-07-17T06:32:01Z
    Message:               Successfully paused database
    Observed Generation:   1
    Reason:                DatabasePauseSucceeded
    Status:                True
    Type:                  DatabasePauseSucceeded
    Last Transition Time:  2024-07-17T06:32:07Z
    Message:               successfully reconciled the Pgpool with updated version
    Observed Generation:   1
    Reason:                UpdatePetSets
    Status:                True
    Type:                  UpdatePetSets
    Last Transition Time:  2024-07-17T06:32:52Z
    Message:               Successfully Restarted Pgpool pods
    Observed Generation:   1
    Reason:                RestartPods
    Status:                True
    Type:                  RestartPods
    Last Transition Time:  2024-07-17T06:32:12Z
    Message:               get pod; ConditionStatus:True; PodName:pp-update-0
    Observed Generation:   1
    Status:                True
    Type:                  GetPod--pp-update-0
    Last Transition Time:  2024-07-17T06:32:12Z
    Message:               evict pod; ConditionStatus:True; PodName:pp-update-0
    Observed Generation:   1
    Status:                True
    Type:                  EvictPod--pp-update-0
    Last Transition Time:  2024-07-17T06:32:47Z
    Message:               check pod running; ConditionStatus:True; PodName:pp-update-0
    Observed Generation:   1
    Status:                True
    Type:                  CheckPodRunning--pp-update-0
    Last Transition Time:  2024-07-17T06:32:52Z
    Message:               Successfully updated Pgpool
    Observed Generation:   1
    Reason:                UpdateDatabase
    Status:                True
    Type:                  UpdateDatabase
    Last Transition Time:  2024-07-17T06:32:52Z
    Message:               Successfully updated Pgpool version
    Observed Generation:   1
    Reason:                Successful
    Status:                True
    Type:                  Successful
  Observed Generation:     1
  Phase:                   Successful
Events:
  Type     Reason                                                         Age    From                         Message
  ----     ------                                                         ----   ----                         -------
  Normal   Starting                                                       2m55s  KubeDB Ops-manager Operator  Start processing for PgpoolOpsRequest: demo/pgpool-version-update
  Normal   Starting                                                       2m55s  KubeDB Ops-manager Operator  Pausing Pgpool databse: demo/pp-update
  Normal   Successful                                                     2m55s  KubeDB Ops-manager Operator  Successfully paused Pgpool database: demo/pp-update for PgpoolOpsRequest: pgpool-version-update
  Normal   UpdatePetSets                                                  2m46s  KubeDB Ops-manager Operator  successfully reconciled the Pgpool with updated version
  Normal   get pod; ConditionStatus:True; PodName:pp-update-0             2m41s  KubeDB Ops-manager Operator  get pod; ConditionStatus:True; PodName:pp-update-0
  Normal   evict pod; ConditionStatus:True; PodName:pp-update-0           2m41s  KubeDB Ops-manager Operator  evict pod; ConditionStatus:True; PodName:pp-update-0
  Normal   check pod running; ConditionStatus:False; PodName:pp-update-0  2m36s  KubeDB Ops-manager Operator  check pod running; ConditionStatus:False; PodName:pp-update-0
  Normal   check pod running; ConditionStatus:True; PodName:pp-update-0   2m6s   KubeDB Ops-manager Operator  check pod running; ConditionStatus:True; PodName:pp-update-0
  Normal   RestartPods                                                    2m1s   KubeDB Ops-manager Operator  Successfully Restarted Pgpool pods
  Normal   Starting                                                       2m1s   KubeDB Ops-manager Operator  Resuming Pgpool database: demo/pp-update
  Normal   Successful                                                     2m1s   KubeDB Ops-manager Operator  Successfully resumed Pgpool database: demo/pp-update for PgpoolOpsRequest: pgpool-version-update

Now, we are going to verify whether the Pgpool and the related PetSets their Pods have the new version image. Let’s check,

$ kubectl get pp -n demo pp-update -o=jsonpath='{.spec.version}{"\n"}'                                                                                          
4.5.0

$ kubectl get petset -n demo pp-update -o=jsonpath='{.spec.template.spec.containers[0].image}{"\n"}'                                                               
mongo:4.0.5

$ kubectl get pods -n demo mg-standalone-0 -o=jsonpath='{.spec.containers[0].image}{"\n"}'                                                                           
ghcr.io/appscode-images/pgpool2:4.5.0@sha256:2697fcad9e11bdc704f6ae0fba85c4451c6b0243140aaaa33e719c3af548bda1

You can see from above, our Pgpool has been updated with the new version. So, the update process is successfully completed.

Cleaning Up

To clean up the Kubernetes resources created by this tutorial, run:

kubectl delete pp -n demo pp-update
kubectl delete pgpoolopsrequest -n demo pgpool-version-update