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Vertical Scale Redis Cluster
This guide will show you how to use KubeDB Enterprise operator to update the resources of a Redis cluster database.
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
KubeDBCommunity and Enterprise 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/redis directory of kubedb/docs repository.
Apply Vertical Scaling on Cluster
Here, we are going to deploy a Redis cluster using a supported version by KubeDB operator. Then we are going to apply vertical scaling on it.
Prepare Redis Cluster Database
Now, we are going to deploy a Redis cluster database with version 5.0.3-v1.
Deploy Redis Cluster
In this section, we are going to deploy a Redis cluster 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-cluster
namespace: demo
spec:
version: 5.0.3-v1
mode: Cluster
cluster:
master: 3
replicas: 1
storageType: Durable
storage:
resources:
requests:
storage: 1Gi
storageClassName: "standard"
accessModes:
- ReadWriteOnce
terminationPolicy: WipeOut
Let’s create the Redis CR we have shown above,
$ kubectl create -f https://github.com/kubedb/docs/raw/v2021.04.16/docs/examples/redis/scaling/rd-cluster.yaml
redis.kubedb.com/redis-cluster created
Now, wait until rd-cluster has status Ready. i.e. ,
$ kubectl get redis -n demo
NAME VERSION STATUS AGE
redis-cluster 5.0.3-v1 Ready 2m30s
Let’s check the Pod containers resources,
$ kubectl get pod -n demo redis-cluster-shard0-0 -o json | jq '.spec.containers[].resources'
{
"limits": {
"cpu": "250m",
"memory": "512Mi"
},
"requests": {
"cpu": "100m",
"memory": "256Mi"
}
}
$ kubectl get pod -n demo redis-cluster-shard1-1 -o json | jq '.spec.containers[].resources'
{
"limits": {
"cpu": "250m",
"memory": "512Mi"
},
"requests": {
"cpu": "100m",
"memory": "256Mi"
}
}
We can see from the above output that there are some default resources set by the operator for pods across all shards. 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 cluster 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: redisops-vertical
namespace: demo
spec:
type: VerticalScaling
databaseRef:
name: redis-cluster
verticalScaling:
redis:
requests:
memory: "300Mi"
cpu: "200m"
limits:
memory: "800Mi"
cpu: "500m"
Here,
spec.databaseRef.namespecifies that we are performing vertical scaling operation onredis-clusterdatabase.spec.typespecifies that we are performingVerticalScalingon our database.spec.VerticalScaling.redisspecifies the desired resources after scaling.
Let’s create the RedisOpsRequest CR we have shown above,
$ kubectl apply -f https://github.com/kubedb/docs/raw/v2021.04.16/docs/examples/redis/scaling/vertical-cluster.yaml
redisopsrequest.ops.kubedb.com/redisops-vertical created
Verify Redis Cluster 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,
$ kubectl get redisopsrequest -n demo redisops-vertical -w
NAME TYPE STATUS AGE
redisops-vertical VerticalScaling Successful 2m11s
We can see from the above output that the RedisOpsRequest has succeeded. If we describe the RedisOpsRequest we will get an overview of the steps that were followed to scale the database.
kubectl describe redisopsrequest -n demo redisops-vertical
Name: redisops-vertical
Namespace: demo
Labels: <none>
Annotations: <none>
API Version: ops.kubedb.com/v1alpha1
Kind: RedisOpsRequest
Metadata:
Creation Timestamp: 2020-11-26T12:02:56Z
Generation: 1
Resource Version: 81466
Self Link: /apis/ops.kubedb.com/v1alpha1/namespaces/demo/redisopsrequests/redisops-vertical
UID: 53b77e5d-31f4-4a24-b282-a85e44420518
Spec:
Database Ref:
Name: redis-cluster
Type: VerticalScaling
Vertical Scaling:
Redis:
Limits:
Cpu: 500m
Memory: 800Mi
Requests:
Cpu: 200m
Memory: 300Mi
Status:
Conditions:
Last Transition Time: 2020-11-26T12:02:56Z
Message: RedisOpsRequest: demo/redisops-vertical is vertically scaling database
Observed Generation: 1
Reason: VerticalScaling
Status: True
Type: Progressing
Last Transition Time: 2020-11-26T12:02:56Z
Message: Successfully paused Redis: redis-cluster
Observed Generation: 1
Reason: PauseDatabase
Status: True
Type: PauseDatabase
Last Transition Time: 2020-11-26T12:02:56Z
Message: Successfully updated StatefulSets Resources
Observed Generation: 1
Reason: UpdateStatefulSetResources
Status: True
Type: UpdateStatefulSetResources
Last Transition Time: 2020-11-26T12:04:01Z
Message: Successfully Restarted Pods With Resources
Observed Generation: 1
Reason: RestartedPodsWithResources
Status: True
Type: RestartedPodsWithResources
Last Transition Time: 2020-11-26T12:04:02Z
Message: Vertical scaling have been done successfully
Observed Generation: 1
Reason: ScalingDone
Status: True
Type: ScalingDone
Last Transition Time: 2020-11-26T12:04:02Z
Message: Successfully resumed Redis: redis-cluster
Observed Generation: 1
Reason: ResumeDatabase
Status: True
Type: ResumeDatabase
Last Transition Time: 2020-11-26T12:04:02Z
Message: RedisOpsRequest: demo/redisops-vertical Successfully Vertically Scaled Database
Observed Generation: 1
Reason: VerticalScaling
Status: True
Type: Successful
Observed Generation: 1
Phase: Successful
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal PauseDatabase 3m44s KubeDB Enterprise Operator Pausing Redis demo/redis-cluster
Normal PauseDatabase 3m44s KubeDB Enterprise Operator Successfully paused Redis demo/redis-cluster
Normal Starting 3m44s KubeDB Enterprise Operator Updating Resources of StatefulSet: redis-cluster-shard0
Normal Starting 3m44s KubeDB Enterprise Operator Updating Resources of StatefulSet: redis-cluster-shard1
Normal Starting 3m44s KubeDB Enterprise Operator Updating Resources of StatefulSet: redis-cluster-shard2
Normal UpdateStatefulSetResources 3m44s KubeDB Enterprise Operator Successfully updated StatefulSets Resources
Normal RestartedPodsWithResources 2m38s KubeDB Enterprise Operator Successfully Restarted Pods With Resources
Normal ResumeDatabase 2m38s KubeDB Enterprise Operator Resuming Redis demo/redis-cluster
Normal ResumeDatabase 2m38s KubeDB Enterprise Operator Successfully resumed Redis demo/redis-cluster
Normal Successful 2m38s KubeDB Enterprise Operator Successfully Completed the OpsRequest
Now, we are going to verify from the Pod yaml whether the resources of the cluster database has updated to meet up the desired state, Let’s check,
$ kubectl get pod -n demo redis-cluster-shard0-0 -o json | jq '.spec.containers[].resources'
{
"limits": {
"cpu": "500m",
"memory": "800Mi"
},
"requests": {
"cpu": "200m",
"memory": "300Mi"
}
}
$ kubectl get pod -n demo redis-cluster-shard1-1 -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 cluster database.
Cleaning up
To clean up the kubernetes resources created by this turorial, run:
kubectl delete redis -n demo redis-cluster
kubectl delete redisopsrequest -n demo redisops-vertical