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Vertical Scale Pgpool
This guide will show you how to use KubeDB Ops-manager operator to update the resources of a Pgpool.
Before You Begin
At first, you need to have a Kubernetes cluster, and the
kubectlcommand-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
KubeDBProvisioner and Ops-manager operator in your cluster following the steps here.You should be familiar with the following
KubeDBconcepts:
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.
Apply Vertical Scaling on Pgpool
Here, we are going to deploy a Pgpool using a supported version by KubeDB operator. Then we are going to apply vertical scaling on it.
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 4.5.0.
Deploy Pgpool
In this section, we are going to deploy a Pgpool. Then, in the next section we will update the resources 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-vertical
namespace: demo
spec:
version: "4.5.0"
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/v2024.8.21/docs/examples/pgpool/scaling/pp-vertical.yaml
pgpool.kubedb.com/pp-vertical created
Now, wait until pp-vertical has status Ready. i.e,
$ kubectl get pp -n demo
NAME TYPE VERSION STATUS AGE
pp-vertical kubedb.com/v1alpha2 4.5.0 Ready 17s
Let’s check the Pod containers resources,
$ kubectl get pod -n demo pp-vertical-0 -o json | jq '.spec.containers[].resources'
{
"limits": {
"cpu": "500m",
"memory": "1Gi"
},
"requests": {
"cpu": "500m",
"memory": "1Gi"
}
}
You can see the Pod has default resources which is assigned by the KubeDB operator.
We are now ready to apply the PgpoolOpsRequest CR to update the resources of this pgpool.
Vertical Scaling
Here, we are going to update the resources of the pgpool to meet the desired resources after scaling.
Create PgpoolOpsRequest
In order to update the resources of the pgpool, we have to create a PgpoolOpsRequest CR with our desired resources. Below is the YAML of the PgpoolOpsRequest CR that we are going to create,
apiVersion: ops.kubedb.com/v1alpha1
kind: PgpoolOpsRequest
metadata:
name: pgpool-scale-vertical
namespace: demo
spec:
type: VerticalScaling
databaseRef:
name: pp-vertical
verticalScaling:
node:
resources:
requests:
memory: "2Gi"
cpu: "1"
limits:
memory: "2Gi"
cpu: "1"
timeout: 5m
apply: IfReady
Here,
spec.databaseRef.namespecifies that we are performing vertical scaling operation onpp-verticalpgpool.spec.typespecifies that we are performingVerticalScalingon our database.spec.VerticalScaling.standalonespecifies the desired resources after scaling.- Have a look here on the respective sections to understand the
timeout&applyfields.
Let’s create the PgpoolOpsRequest CR we have shown above,
$ kubectl apply -f https://github.com/kubedb/docs/raw/v2024.8.21/docs/examples/pgpool/scaling/vertical-scaling/pp-vertical-ops.yaml
pgpoolopsrequest.ops.kubedb.com/pgpool-scale-vertical created
Verify Pgpool resources updated successfully
If everything goes well, KubeDB Ops-manager operator will update the resources of Pgpool object and related PetSet and Pods.
Let’s wait for PgpoolOpsRequest to be Successful. Run the following command to watch PgpoolOpsRequest CR,
$ kubectl get pgpoolopsrequest -n demo
Every 2.0s: kubectl get pgpoolopsrequest -n demo
NAME TYPE STATUS AGE
pgpool-scale-vertical VerticalScaling Successful 3m42s
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 scale the pgpool.
$ kubectl describe pgpoolopsrequest -n demo pgpool-scale-vertical
Name: pgpool-scale-vertical
Namespace: demo
Labels: <none>
Annotations: <none>
API Version: ops.kubedb.com/v1alpha1
Kind: PgpoolOpsRequest
Metadata:
Creation Timestamp: 2024-07-17T09:44:22Z
Generation: 1
Resource Version: 68270
UID: 62a105f7-e7b9-444e-9303-79818fccfdef
Spec:
Apply: IfReady
Database Ref:
Name: pp-vertical
Timeout: 5m
Type: VerticalScaling
Vertical Scaling:
Node:
Resources:
Limits:
Cpu: 1
Memory: 2Gi
Requests:
Cpu: 1
Memory: 2Gi
Status:
Conditions:
Last Transition Time: 2024-07-17T09:44:22Z
Message: Pgpool ops-request has started to vertically scaling the Pgpool nodes
Observed Generation: 1
Reason: VerticalScaling
Status: True
Type: VerticalScaling
Last Transition Time: 2024-07-17T09:44:25Z
Message: Successfully paused database
Observed Generation: 1
Reason: DatabasePauseSucceeded
Status: True
Type: DatabasePauseSucceeded
Last Transition Time: 2024-07-17T09:44:25Z
Message: Successfully updated PetSets Resources
Observed Generation: 1
Reason: UpdatePetSets
Status: True
Type: UpdatePetSets
Last Transition Time: 2024-07-17T09:45:10Z
Message: Successfully Restarted Pods With Resources
Observed Generation: 1
Reason: RestartPods
Status: True
Type: RestartPods
Last Transition Time: 2024-07-17T09:44:30Z
Message: get pod; ConditionStatus:True; PodName:pp-vertical-0
Observed Generation: 1
Status: True
Type: GetPod--pp-vertical-0
Last Transition Time: 2024-07-17T09:44:30Z
Message: evict pod; ConditionStatus:True; PodName:pp-vertical-0
Observed Generation: 1
Status: True
Type: EvictPod--pp-vertical-0
Last Transition Time: 2024-07-17T09:45:05Z
Message: check pod running; ConditionStatus:True; PodName:pp-vertical-0
Observed Generation: 1
Status: True
Type: CheckPodRunning--pp-vertical-0
Last Transition Time: 2024-07-17T09:45:10Z
Message: Successfully completed the vertical scaling for Pgpool
Observed Generation: 1
Reason: Successful
Status: True
Type: Successful
Observed Generation: 1
Phase: Successful
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Starting 4m16s KubeDB Ops-manager Operator Start processing for PgpoolOpsRequest: demo/pgpool-scale-vertical
Normal Starting 4m16s KubeDB Ops-manager Operator Pausing Pgpool databse: demo/pp-vertical
Normal Successful 4m16s KubeDB Ops-manager Operator Successfully paused Pgpool database: demo/pp-vertical for PgpoolOpsRequest: pgpool-scale-vertical
Normal UpdatePetSets 4m13s KubeDB Ops-manager Operator Successfully updated PetSets Resources
Warning get pod; ConditionStatus:True; PodName:pp-vertical-0 4m8s KubeDB Ops-manager Operator get pod; ConditionStatus:True; PodName:pp-vertical-0
Warning evict pod; ConditionStatus:True; PodName:pp-vertical-0 4m8s KubeDB Ops-manager Operator evict pod; ConditionStatus:True; PodName:pp-vertical-0
Warning check pod running; ConditionStatus:False; PodName:pp-vertical-0 4m3s KubeDB Ops-manager Operator check pod running; ConditionStatus:False; PodName:pp-vertical-0
Warning check pod running; ConditionStatus:True; PodName:pp-vertical-0 3m33s KubeDB Ops-manager Operator check pod running; ConditionStatus:True; PodName:pp-vertical-0
Normal RestartPods 3m28s KubeDB Ops-manager Operator Successfully Restarted Pods With Resources
Normal Starting 3m28s KubeDB Ops-manager Operator Resuming Pgpool database: demo/pp-vertical
Normal Successful 3m28s KubeDB Ops-manager Operator Successfully resumed Pgpool database: demo/pp-vertical for PgpoolOpsRequest: pgpool-scale-vertical
Now, we are going to verify from the Pod yaml whether the resources of the pgpool has updated to meet up the desired state, Let’s check,
$ kubectl get pod -n demo pp-vertical-0 -o json | jq '.spec.containers[].resources'
{
"limits": {
"cpu": "1",
"memory": "2Gi"
},
"requests": {
"cpu": "1",
"memory": "2Gi"
}
}
The above output verifies that we have successfully scaled up the resources of the Pgpool.
Cleaning Up
To clean up the Kubernetes resources created by this tutorial, run:
kubectl delete pp -n demo pp-vertical
kubectl delete pgpoolopsrequest -n demo pgpool-scale-vertical