New to KubeDB? Please start here.

Vertical Scale Standalone Redis

This guide will show you how to use KubeDB Enterprise operator to update the resources of a standalone Redis 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:

  • Redis
  • RedisOpsRequest
  • 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

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

Apply Vertical Scaling on Standalone

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

Prepare Redis Standalone Database

Now, we are going to deploy a Redis standalone database with version 6.2.14.

Deploy Redis standalone

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

apiVersion: kubedb.com/v1alpha2
kind: Redis
metadata:
  name: redis-quickstart
  namespace: demo
spec:
  version: 6.2.14
  storageType: Durable
  storage:
    storageClassName: "standard"
    accessModes:
    - ReadWriteOnce
    resources:
      requests:
        storage: 1Gi
  podTemplate:
    spec:
      resources:
        requests:
          cpu: "100m"
          memory: "100Mi"

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

$ kubectl create -f https://github.com/kubedb/docs/raw/v2024.1.26-rc.0/docs/examples/redis/scaling/vertical-scaling/rd-standalone.yaml
redis.kubedb.com/redis-quickstart created

Now, wait until rd-quickstart has status Ready. i.e. ,

$ kubectl get redis -n demo
NAME               VERSION    STATUS   AGE
redis-quickstart   6.2.14   Ready    2m30s

Let’s check the Pod containers resources,

$ kubectl get pod -n demo redis-quickstart-0 -o json | jq '.spec.containers[].resources'
{
  "limits": {
    "memory": "100Mi"
  },
  "requests": {
    "cpu": "100m",
    "memory": "100Mi"
  }
}

We can see from the above output that there are some default resources set by the operator. And the scheduler will choose the best suitable node to place the container of the Pod.

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

Vertical Scaling

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

Create RedisOpsRequest

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

apiVersion: ops.kubedb.com/v1alpha1
kind: RedisOpsRequest
metadata:
  name: redisopsstandalone
  namespace: demo
spec:
  type: VerticalScaling
  databaseRef:
    name: redis-quickstart
  verticalScaling:
    redis:
      resources:
        requests:
          memory: "300Mi"
          cpu: "200m"
        limits:
          memory: "800Mi"
          cpu: "500m"

Here,

• spec.databaseRef.name specifies that we are performing vertical scaling operation on redis-quickstart database.
• spec.type specifies that we are performing VerticalScaling on our database.
• spec.verticalScaling.redis specifies the desired resources after scaling.

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

$ kubectl apply -f https://github.com/kubedb/docs/raw/v2024.1.26-rc.0/docs/examples/redis/scaling/vertical-scaling/vertical-standalone.yaml
redisopsrequest.ops.kubedb.com/redisopsstandalone created

Verify Redis Standalone resources updated successfully

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

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

$ watch kubectl get redisopsrequest -n demo redisopsstandalone
NAME                 TYPE              STATUS       AGE
redisopsstandalone   VerticalScaling   Successful   26s

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

$ kubectl get pod -n demo redis-quickstart-0 -o json | jq '.spec.containers[].resources'
{
  "limits": {
    "cpu": "500m",
    "memory": "800Mi"
  },
  "requests": {
    "cpu": "200m",
    "memory": "300Mi"
  }
}

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

Cleaning up

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

$ kubectl patch -n demo rd/redis-quickstart -p '{"spec":{"terminationPolicy":"WipeOut"}}' --type="merge"
redis.kubedb.com/redis-quickstart patched

$ kubectl delete -n demo redis redis-quickstart
redis.kubedb.com "redis-quickstart" deleted

$ kubectl delete redisopsrequest -n demo redisopsstandalone
redisopsrequest.ops.kubedb.com "redisopsstandalone" deleted