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Vertical Scale ZooKeeper Standalone
This guide will show you how to use KubeDB Ops-manager operator to update the resources of a ZooKeeper standalone 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
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/zookeeper directory of kubedb/docs repository.
Apply Vertical Scaling on Standalone
Here, we are going to deploy a ZooKeeper standalone using a supported version by KubeDB operator. Then we are going to apply vertical scaling on it.
Prepare ZooKeeper Standalone Database
Now, we are going to deploy a ZooKeeper standalone database with version 3.8.3.
Deploy ZooKeeper standalone
In this section, we are going to deploy a ZooKeeper standalone database. Then, in the next section we will update the resources of the database using ZooKeeperOpsRequest CRD. Below is the YAML of the ZooKeeper CR that we are going to create,
apiVersion: kubedb.com/v1alpha2
kind: ZooKeeper
metadata:
name: zk-quickstart
namespace: demo
spec:
version: "3.8.3"
adminServerPort: 8080
replicas: 3
storage:
resources:
requests:
storage: "1Gi"
storageClassName: "standard"
accessModes:
- ReadWriteOnce
deletionPolicy: "WipeOut"
Let’s create the ZooKeeper CR we have shown above,
$ kubectl create -f https://github.com/kubedb/docs/raw/v2025.3.20-rc.1/docs/examples/zookeeper/scaling/zookeeper.yaml
zookeeper.kubedb.com/zk-quickstart created
Now, wait until zk-quickstart has status Ready. i.e,
$ kubectl get zk -n demo
NAME VERSION STATUS AGE
zk-quickstart 3.8.3 Ready 5m56s
Let’s check the Pod containers resources,
$ kubectl get pod -n demo zk-quickstart-0 -o json | jq '.spec.containers[].resources'
{
"limits": {
"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 ZooKeeperOpsRequest 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 ZooKeeperOpsRequest
In order to update the resources of the database, we have to create a ZooKeeperOpsRequest CR with our desired resources. Below is the YAML of the ZooKeeperOpsRequest CR that we are going to create,
apiVersion: ops.kubedb.com/v1alpha1
kind: ZooKeeperOpsRequest
metadata:
name: vscale
namespace: demo
spec:
databaseRef:
name: zk-quickstart
type: VerticalScaling
verticalScaling:
node:
resources:
limits:
cpu: 1
memory: 2Gi
requests:
cpu: 1
memory: 2Gi
timeout: 5m
apply: IfReady
Here,
spec.databaseRef.namespecifies that we are performing vertical scaling operation onvscaledatabase.spec.typespecifies that we are performingVerticalScalingon our database.spec.VerticalScaling.nodespecifies the desired resources after scaling.- Have a look here on the respective sections to understand the
timeout&applyfields.
Let’s create the ZooKeeperOpsRequest CR we have shown above,
$ kubectl apply -f https://github.com/kubedb/docs/raw/v2025.3.20-rc.1/docs/examples/zookeeper/scaling/vertical-scaling/zk-vscale.yaml
zookeeperopsrequest.ops.kubedb.com/vscale created
Verify ZooKeeper Standalone resources updated successfully
If everything goes well, KubeDB Ops-manager operator will update the resources of ZooKeeper object and related Petsets and Pods.
Let’s wait for ZooKeeperOpsRequest to be Successful. Run the following command to watch ZooKeeperOpsRequest CR,
$ kubectl get zookeeperopsrequest -n demo
Every 2.0s: kubectl get zookeeperopsrequest -n demo
NAME TYPE STATUS AGE
vscale VerticalScaling Successful 108s
We can see from the above output that the ZooKeeperOpsRequest has succeeded. If we describe the ZooKeeperOpsRequest we will get an overview of the steps that were followed to scale the database.
$ kubectl describe zookeeperopsrequest -n demo vscale
Name: vscale
Namespace: demo
Labels: <none>
Annotations: <none>
API Version: ops.kubedb.com/v1alpha1
Kind: ZooKeeperOpsRequest
Metadata:
Creation Timestamp: 2024-10-24T11:21:28Z
Generation: 1
Resource Version: 1151711
UID: 53ba9aef-cfa6-40f1-a5a8-6055bafb0c7b
Spec:
Apply: IfReady
Database Ref:
Name: zk-quickstart
Timeout: 5m
Type: VerticalScaling
Vertical Scaling:
Node:
Resources:
Limits:
Cpu: 1
Memory: 2Gi
Requests:
Cpu: 1
Memory: 2Gi
Status:
Conditions:
Last Transition Time: 2024-10-24T11:21:28Z
Message: ZooKeeper ops-request has started to vertically scaling the ZooKeeper nodes
Observed Generation: 1
Reason: VerticalScaling
Status: True
Type: VerticalScaling
Last Transition Time: 2024-10-24T11:21:31Z
Message: Successfully updated PetSets Resources
Observed Generation: 1
Reason: UpdatePetSets
Status: True
Type: UpdatePetSets
Last Transition Time: 2024-10-24T11:21:31Z
Message: Successfully Restarted Pods With Resources
Observed Generation: 1
Reason: RestartPods
Status: False
Type: RestartPods
Last Transition Time: 2024-10-24T11:21:36Z
Message: get pod; ConditionStatus:True; PodName:zk-quickstart-0
Observed Generation: 1
Status: True
Type: GetPod--zk-quickstart-0
Last Transition Time: 2024-10-24T11:21:36Z
Message: evict pod; ConditionStatus:True; PodName:zk-quickstart-0
Observed Generation: 1
Status: True
Type: EvictPod--zk-quickstart-0
Last Transition Time: 2024-10-24T11:21:41Z
Message: running pod; ConditionStatus:False
Observed Generation: 1
Status: False
Type: RunningPod
Last Transition Time: 2024-10-24T11:22:16Z
Message: get pod; ConditionStatus:True; PodName:zk-quickstart-1
Observed Generation: 1
Status: True
Type: GetPod--zk-quickstart-1
Last Transition Time: 2024-10-24T11:22:16Z
Message: evict pod; ConditionStatus:True; PodName:zk-quickstart-1
Observed Generation: 1
Status: True
Type: EvictPod--zk-quickstart-1
Last Transition Time: 2024-10-24T11:22:56Z
Message: get pod; ConditionStatus:True; PodName:zk-quickstart-2
Observed Generation: 1
Status: True
Type: GetPod--zk-quickstart-2
Last Transition Time: 2024-10-24T11:22:56Z
Message: evict pod; ConditionStatus:True; PodName:zk-quickstart-2
Observed Generation: 1
Status: True
Type: EvictPod--zk-quickstart-2
Observed Generation: 1
Phase: Progressing
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Starting 3m24s KubeDB Ops-manager Operator Start processing for ZooKeeperOpsRequest: demo/vscale
Normal Starting 3m24s KubeDB Ops-manager Operator Pausing ZooKeeper database: demo/zk-quickstart
Normal Successful 3m24s KubeDB Ops-manager Operator Successfully paused ZooKeeper database: demo/zk-quickstart for ZooKeeperOpsRequest: vscale
Normal UpdatePetSets 3m21s KubeDB Ops-manager Operator Successfully updated PetSets Resources
Warning get pod; ConditionStatus:True; PodName:zk-quickstart-0 3m16s KubeDB Ops-manager Operator get pod; ConditionStatus:True; PodName:zk-quickstart-0
Warning evict pod; ConditionStatus:True; PodName:zk-quickstart-0 3m16s KubeDB Ops-manager Operator evict pod; ConditionStatus:True; PodName:zk-quickstart-0
Warning running pod; ConditionStatus:False 3m11s KubeDB Ops-manager Operator running pod; ConditionStatus:False
Warning get pod; ConditionStatus:True; PodName:zk-quickstart-1 2m36s KubeDB Ops-manager Operator get pod; ConditionStatus:True; PodName:zk-quickstart-1
Warning evict pod; ConditionStatus:True; PodName:zk-quickstart-1 2m36s KubeDB Ops-manager Operator evict pod; ConditionStatus:True; PodName:zk-quickstart-1
Warning get pod; ConditionStatus:True; PodName:zk-quickstart-2 116s KubeDB Ops-manager Operator get pod; ConditionStatus:True; PodName:zk-quickstart-2
Warning evict pod; ConditionStatus:True; PodName:zk-quickstart-2 116s KubeDB Ops-manager Operator evict pod; ConditionStatus:True; PodName:zk-quickstart-2
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 zk-quickstart-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 ZooKeeper standalone database.
Cleaning Up
To clean up the Kubernetes resources created by this tutorial, run:
kubectl delete zk -n demo zk-quickstart
kubectl delete zookeeperopsrequest -n demo vscale