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Vertical Scale PerconaXtraDB Cluster

This guide will show you how to use KubeDB Enterprise operator to update the resources of a PerconaXtraDB cluster database.

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 Community and Enterprise operator in your cluster following the steps here.

• You should be familiar with the following KubeDB concepts:

  • PerconaXtraDB
  • Clustering
  • PerconaXtraDBOpsRequest
  • Vertical Scaling Overview

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

$ kubectl create ns demo
namespace/demo created

Apply Vertical Scaling on Cluster

Here, we are going to deploy a PerconaXtraDB cluster using a supported version by KubeDB operator. Then we are going to apply vertical scaling on it.

Prepare PerconaXtraDB Cluster

Now, we are going to deploy a PerconaXtraDB cluster database with version 8.0.26.

Vertical Scaling for PerconaXtraDB Standalone can be performed in the same way as PerconaXtraDB Cluster. Only remove the spec.replicas field from the below yaml to deploy a PerconaXtraDB Standalone.

Deploy PerconaXtraDB Cluster

In this section, we are going to deploy a PerconaXtraDB cluster database. Then, in the next section we will update the resources of the database using PerconaXtraDBOpsRequest CRD. Below is the YAML of the PerconaXtraDB CR that we are going to create,

apiVersion: kubedb.com/v1alpha2
kind: PerconaXtraDB
metadata:
  name: sample-pxc
  namespace: demo
spec:
  version: "8.0.26"
  replicas: 3
  storageType: Durable
  storage:
    storageClassName: "standard"
    accessModes:
    - ReadWriteOnce
    resources:
      requests:
        storage: 1Gi
  terminationPolicy: WipeOut

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

$ kubectl create -f https://github.com/kubedb/docs/raw/v2023.01.17/docs/guides/percona-xtradb/scaling/vertical-scaling/cluster/example/sample-pxc.yaml
perconaxtradb.kubedb.com/sample-pxc created

Now, wait until sample-pxc has status Ready. i.e,

$ kubectl get perconaxtradb -n demo
NAME             VERSION    STATUS     AGE
sample-pxc    8.0.26     Ready     3m46s

Let’s check the Pod containers resources,

$ kubectl get pod -n demo sample-pxc-0 -o json | jq '.spec.containers[].resources'
{
  "limits": {
    "cpu": "500m",
    "memory": "1Gi"
  },
  "requests": {
    "cpu": "500m",
    "memory": "1Gi"
  }
}

You can see the Pod has the default resources which is assigned by Kubedb operator.

We are now ready to apply the PerconaXtraDBOpsRequest CR to update the resources of this database.

Vertical Scaling

Here, we are going to update the resources of the database to meet the desired resources after scaling.

Create PerconaXtraDBOpsRequest

In order to update the resources of the database, we have to create a PerconaXtraDBOpsRequest CR with our desired resources. Below is the YAML of the PerconaXtraDBOpsRequest CR that we are going to create,

apiVersion: ops.kubedb.com/v1alpha1
kind: PerconaXtraDBOpsRequest
metadata:
  name: pxops-vscale
  namespace: demo
spec:
  type: VerticalScaling
  databaseRef:
    name: sample-pxc
  verticalScaling:
    perconaxtradb:
      requests:
        memory: "1.2Gi"
        cpu: "0.6"
      limits:
        memory: "1.2Gi"
        cpu: "0.6"

Here,

• spec.databaseRef.name specifies that we are performing vertical scaling operation on sample-pxc database.
• spec.type specifies that we are performing VerticalScaling on our database.
• spec.VerticalScaling.perconaxtradb specifies the desired resources after scaling.

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

$ kubectl apply -f https://github.com/kubedb/docs/raw/v2023.01.17/docs/guides/percona-xtradb/scaling/vertical-scaling/cluster/example/pxops-vscale.yaml
perconaxtradbopsrequest.ops.kubedb.com/pxops-vscale created

Verify PerconaXtraDB Cluster resources updated successfully

If everything goes well, KubeDB Enterprise operator will update the resources of PerconaXtraDB object and related StatefulSets and Pods.

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

$ kubectl get perconaxtradbopsrequest -n demo
Every 2.0s: kubectl get perconaxtradbopsrequest -n demo
NAME                     TYPE              STATUS       AGE
pxops-vscale        VerticalScaling      Successful    3m56s

We can see from the above output that the PerconaXtraDBOpsRequest has succeeded. Now, we are going to verify from one of the Pod yaml whether the resources of the database has updated to meet up the desired state, Let’s check,

$ kubectl get pod -n demo sample-pxc-0 -o json | jq '.spec.containers[].resources'
{
  "limits": {
    "cpu": "600m",
    "memory": "1288490188800m"
  },
  "requests": {
    "cpu": "600m",
    "memory": "1288490188800m"
  }
}

The above output verifies that we have successfully scaled up the resources of the PerconaXtraDB database.

Cleaning Up

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

$ kubectl delete perconaxtradb -n demo sample-pxc
$ kubectl delete perconaxtradbopsrequest -n demo pxops-vscale