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New to KubeDB? Please start here.

Horizontal Scale Elasticsearch Combined Cluster

This guide will show you how to use KubeDB Ops-manager operator to scale the Elasticsearch combined cluster.

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 Provisioner and Ops-manager operator in your cluster following the steps here.

  • You should be familiar with the following KubeDB concepts:

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/Elasticsearch directory of kubedb/docs repository.

Apply Horizontal Scaling on Combined Cluster

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

Prepare Elasticsearch Combined cluster

Now, we are going to deploy a Elasticsearch combined cluster with version xpack-9.1.4.

Deploy Elasticsearch combined cluster

In this section, we are going to deploy a Elasticsearch combined cluster. Then, in the next section we will scale the cluster using ElasticsearchOpsRequest CRD. Below is the YAML of the Elasticsearch CR that we are going to create,

apiVersion: kubedb.com/v1
kind: Elasticsearch
metadata:
  name: es
  namespace: demo
spec:
  version: xpack-9.1.4
  enableSSL: true
  replicas: 2
  storageType: Durable
  storage:
    storageClassName: "standard"
    accessModes:
      - ReadWriteOnce
    resources:
      requests:
        storage: 1Gi
  deletionPolicy: WipeOut

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

$ kubectl create -f https://github.com/kubedb/docs/raw/v2025.10.17/docs/examples/overview/quickstart/elasticsearch/yamls/elasticsearch-v1.yaml
Elasticsearch.kubedb.com/es created

Now, wait until es has status Ready. i.e,

$ kubectl get es -n demo
NAME   VERSION       STATUS   AGE
es     xpack-9.1.4   Ready    3m53s

Let’s check the number of replicas has from Elasticsearch object, number of pods the petset have,

$ kubectl get elasticsearch -n demo es -o json | jq '.spec.replicas'
2
$ kubectl get petsets -n demo es -o json | jq '.spec.replicas'
2

We can see from both command that the cluster has 2 replicas.

Also, we can verify the replicas of the combined from an internal Elasticsearch command by exec into a replica.

Now lets check the number of replicas,

$ kubectl get all,secret,pvc -n demo -l 'app.kubernetes.io/instance=es'
NAME       READY   STATUS    RESTARTS   AGE
pod/es-0   1/1     Running   0          5m
pod/es-1   1/1     Running   0          4m54s

NAME                TYPE        CLUSTER-IP     EXTERNAL-IP   PORT(S)    AGE
service/es          ClusterIP   10.43.72.228   <none>        9200/TCP   5m5s
service/es-master   ClusterIP   None           <none>        9300/TCP   5m5s
service/es-pods     ClusterIP   None           <none>        9200/TCP   5m5s

NAME                                    TYPE                       VERSION   AGE
appbinding.appcatalog.appscode.com/es   kubedb.com/elasticsearch   9.1.4     5m2s

NAME                                    TYPE                       DATA   AGE
secret/es-apm-system-cred               kubernetes.io/basic-auth   2      5m4s
secret/es-auth                          kubernetes.io/basic-auth   2      5m8s
secret/es-beats-system-cred             kubernetes.io/basic-auth   2      5m4s
secret/es-ca-cert                       kubernetes.io/tls          2      5m9s
secret/es-client-cert                   kubernetes.io/tls          3      5m8s
secret/es-config                        Opaque                     1      5m8s
secret/es-http-cert                     kubernetes.io/tls          3      5m8s
secret/es-kibana-system-cred            kubernetes.io/basic-auth   2      5m4s
secret/es-logstash-system-cred          kubernetes.io/basic-auth   2      5m4s
secret/es-remote-monitoring-user-cred   kubernetes.io/basic-auth   2      5m4s
secret/es-transport-cert                kubernetes.io/tls          3      5m8s

NAME                              STATUS   VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS   VOLUMEATTRIBUTESCLASS   AGE
persistentvolumeclaim/data-es-0   Bound    pvc-7c8cc17d-7427-4411-9262-f213e826540b   1Gi        RWO            standard     <unset>                 5m5s
persistentvolumeclaim/data-es-1   Bound    pvc-f2cf7ac9-b0c2-4c44-93dc-476cc06c25b4   1Gi        RWO            standard     <unset>                 4m59s

We can see from the above output that the Elasticsearch has 2 nodes.

We are now ready to apply the ElasticsearchOpsRequest CR to scale this cluster.

Scale Up Replicas

Here, we are going to scale up the replicas of the combined cluster to meet the desired number of replicas after scaling.

Create ElasticsearchOpsRequest

In order to scale up the replicas of the combined cluster, we have to create a ElasticsearchOpsRequest CR with our desired replicas. Below is the YAML of the ElasticsearchOpsRequest CR that we are going to create,

apiVersion: ops.kubedb.com/v1alpha1
kind: ElasticsearchOpsRequest
metadata:
  name: esops-hscale-up-combined
  namespace: demo
spec:
  type: HorizontalScaling
  databaseRef:
    name: es
  horizontalScaling:
    node: 3

Here,

  • spec.databaseRef.name specifies that we are performing horizontal scaling operation on es cluster.
  • spec.type specifies that we are performing HorizontalScaling on Elasticsearch.
  • spec.horizontalScaling.node specifies the desired replicas after scaling.

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

$ kubectl apply -f https://github.com/kubedb/docs/raw/v2025.10.17/docs/examples/elasticsearch/scaling/horizontal/Elasticsearch-hscale-up-combined.yaml
Elasticsearchopsrequest.ops.kubedb.com/esops-hscale-up-combined created

Verify Combined cluster replicas scaled up successfully

If everything goes well, KubeDB Ops-manager operator will update the replicas of Elasticsearch object and related PetSets and Pods.

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

$ kubectl get Elasticsearchopsrequest -n demo
NAME          TYPE                STATUS       AGE
esops-hscale-up-combined   HorizontalScaling   Successful   2m42s

We can see from the above output that the ElasticsearchOpsRequest has succeeded. If we describe the ElasticsearchOpsRequest we will get an overview of the steps that were followed to scale the cluster.

$ kubectl describe Elasticsearchopsrequests -n demo esops-hscale-up-combined
Name:         esops-hscale-up-combined
Namespace:    demo
Labels:       <none>
Annotations:  <none>
API Version:  ops.kubedb.com/v1alpha1
Kind:         ElasticsearchOpsRequest
Metadata:
  Creation Timestamp:  2025-11-13T10:25:18Z
  Generation:          1
  Resource Version:    810747
  UID:                 29134aef-1379-4e4f-91c8-23b1cf74c784
Spec:
  Apply:  IfReady
  Database Ref:
    Name:  es
  Horizontal Scaling:
    Node:  3
  Type:    HorizontalScaling
Status:
  Conditions:
    Last Transition Time:  2025-11-13T10:25:58Z
    Message:               Elasticsearch ops request is horizontally scaling the nodes.
    Observed Generation:   1
    Reason:                HorizontalScale
    Status:                True
    Type:                  HorizontalScale
    Last Transition Time:  2025-11-13T10:26:06Z
    Message:               patch pet set; ConditionStatus:True
    Observed Generation:   1
    Status:                True
    Type:                  PatchPetSet
    Last Transition Time:  2025-11-13T10:26:26Z
    Message:               is node in cluster; ConditionStatus:True
    Observed Generation:   1
    Status:                True
    Type:                  IsNodeInCluster
    Last Transition Time:  2025-11-13T10:26:31Z
    Message:               ScaleUp es nodes
    Observed Generation:   1
    Reason:                HorizontalScaleCombinedNode
    Status:                True
    Type:                  HorizontalScaleCombinedNode
    Last Transition Time:  2025-11-13T10:26:36Z
    Message:               successfully updated Elasticsearch CR
    Observed Generation:   1
    Reason:                UpdateDatabase
    Status:                True
    Type:                  UpdateDatabase
    Last Transition Time:  2025-11-13T10:26:36Z
    Message:               Successfully Horizontally Scaled.
    Observed Generation:   1
    Reason:                Successful
    Status:                True
    Type:                  Successful
  Observed Generation:     1
  Phase:                   Successful
Events:
  Type     Reason                                     Age    From                         Message
  ----     ------                                     ----   ----                         -------
  Normal   PauseDatabase                              2m54s  KubeDB Ops-manager Operator  Pausing Elasticsearch demo/es
  Warning  patch pet set; ConditionStatus:True        2m46s  KubeDB Ops-manager Operator  patch pet set; ConditionStatus:True
  Warning  is node in cluster; ConditionStatus:False  2m41s  KubeDB Ops-manager Operator  is node in cluster; ConditionStatus:False
  Warning  is node in cluster; ConditionStatus:True   2m26s  KubeDB Ops-manager Operator  is node in cluster; ConditionStatus:True
  Normal   HorizontalScaleCombinedNode                2m21s  KubeDB Ops-manager Operator  ScaleUp es nodes
  Normal   UpdateDatabase                             2m16s  KubeDB Ops-manager Operator  successfully updated Elasticsearch CR
  Normal   ResumeDatabase                             2m16s  KubeDB Ops-manager Operator  Resuming Elasticsearch demo/es
  Normal   ResumeDatabase                             2m16s  KubeDB Ops-manager Operator  Successfully resumed Elasticsearch demo/es
  Normal   Successful                                 2m16s  KubeDB Ops-manager Operator  Successfully Horizontally Scaled Database
bonusree@bonusree-HP-ProBook-450-G4 ~>

Now, we are going to verify the number of replicas this cluster has from the Elasticsearch object, number of pods the petset have,

$ kubectl get Elasticsearch -n demo es -o json | jq '.spec.replicas'
3

$ kubectl get petset -n demo es -o json | jq '.spec.replicas'
3

From all the above outputs we can see that the brokers of the combined Elasticsearch is 3. That means we have successfully scaled up the replicas of the Elasticsearch combined cluster.

Scale Down Replicas

Here, we are going to scale down the replicas of the Elasticsearch combined cluster to meet the desired number of replicas after scaling.

Create ElasticsearchOpsRequest

In order to scale down the replicas of the Elasticsearch combined cluster, we have to create a ElasticsearchOpsRequest CR with our desired replicas. Below is the YAML of the ElasticsearchOpsRequest CR that we are going to create,

apiVersion: ops.kubedb.com/v1alpha1
kind: ElasticsearchOpsRequest
metadata:
  name: esops-hscale-down-combined
  namespace: demo
spec:
  type: HorizontalScaling
  databaseRef:
    name: es
  horizontalScaling:
    node: 2

Here,

  • spec.databaseRef.name specifies that we are performing horizontal scaling down operation on es cluster.
  • spec.type specifies that we are performing HorizontalScaling on Elasticsearch.
  • spec.horizontalScaling.node specifies the desired replicas after scaling.

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

$ kubectl apply -f https://github.com/kubedb/docs/raw/v2025.10.17/docs/examples/elasticsearch/scaling/horizontal/Elasticsearch-hscale-down-combined.yaml
Elasticsearchopsrequest.ops.kubedb.com/esops-hscale-down-combined created

Verify Combined cluster replicas scaled down successfully

If everything goes well, KubeDB Ops-manager operator will update the replicas of Elasticsearch object and related PetSets and Pods.

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

$ kubectl get Elasticsearchopsrequest -n demo
NAME                         TYPE                STATUS       AGE
esops-hscale-down-combined   HorizontalScaling   Successful   76s

We can see from the above output that the ElasticsearchOpsRequest has succeeded. If we describe the ElasticsearchOpsRequest we will get an overview of the steps that were followed to scale the cluster.

$  kubectl describe Elasticsearchopsrequests -n demo esops-hscale-down-combined
Name:         esops-hscale-down-combined
Namespace:    demo
Labels:       <none>
Annotations:  <none>
API Version:  ops.kubedb.com/v1alpha1
Kind:         ElasticsearchOpsRequest
Metadata:
  Creation Timestamp:  2025-11-13T10:46:22Z
  Generation:          1
  Resource Version:    811301
  UID:                 558530d7-5d02-4757-b459-476129b411d6
Spec:
  Apply:  IfReady
  Database Ref:
    Name:  es
  Horizontal Scaling:
    Node:  2
  Type:    HorizontalScaling
Status:
  Conditions:
    Last Transition Time:  2025-11-13T10:46:22Z
    Message:               Elasticsearch ops request is horizontally scaling the nodes.
    Observed Generation:   1
    Reason:                HorizontalScale
    Status:                True
    Type:                  HorizontalScale
    Last Transition Time:  2025-11-13T10:46:30Z
    Message:               create es client; ConditionStatus:True
    Observed Generation:   1
    Status:                True
    Type:                  CreateEsClient
    Last Transition Time:  2025-11-13T10:46:30Z
    Message:               get voting config exclusion; ConditionStatus:True
    Observed Generation:   1
    Status:                True
    Type:                  GetVotingConfigExclusion
    Last Transition Time:  2025-11-13T10:46:31Z
    Message:               exclude node allocation; ConditionStatus:True
    Observed Generation:   1
    Status:                True
    Type:                  ExcludeNodeAllocation
    Last Transition Time:  2025-11-13T10:46:31Z
    Message:               get used data nodes; ConditionStatus:True
    Observed Generation:   1
    Status:                True
    Type:                  GetUsedDataNodes
    Last Transition Time:  2025-11-13T10:46:31Z
    Message:               move data; ConditionStatus:True
    Observed Generation:   1
    Status:                True
    Type:                  MoveData
    Last Transition Time:  2025-11-13T10:46:31Z
    Message:               patch pet set; ConditionStatus:True
    Observed Generation:   1
    Status:                True
    Type:                  PatchPetSet
    Last Transition Time:  2025-11-13T10:46:35Z
    Message:               get pod; ConditionStatus:True
    Observed Generation:   1
    Status:                True
    Type:                  GetPod
    Last Transition Time:  2025-11-13T10:46:35Z
    Message:               delete pvc; ConditionStatus:True
    Observed Generation:   1
    Status:                True
    Type:                  DeletePvc
    Last Transition Time:  2025-11-13T10:46:40Z
    Message:               get pvc; ConditionStatus:True
    Observed Generation:   1
    Status:                True
    Type:                  GetPvc
    Last Transition Time:  2025-11-13T10:46:45Z
    Message:               delete voting config exclusion; ConditionStatus:True
    Observed Generation:   1
    Status:                True
    Type:                  DeleteVotingConfigExclusion
    Last Transition Time:  2025-11-13T10:46:45Z
    Message:               delete node allocation exclusion; ConditionStatus:True
    Observed Generation:   1
    Status:                True
    Type:                  DeleteNodeAllocationExclusion
    Last Transition Time:  2025-11-13T10:46:45Z
    Message:               ScaleDown es nodes
    Observed Generation:   1
    Reason:                HorizontalScaleCombinedNode
    Status:                True
    Type:                  HorizontalScaleCombinedNode
    Last Transition Time:  2025-11-13T10:46:51Z
    Message:               successfully updated Elasticsearch CR
    Observed Generation:   1
    Reason:                UpdateDatabase
    Status:                True
    Type:                  UpdateDatabase
    Last Transition Time:  2025-11-13T10:46:51Z
    Message:               Successfully Horizontally Scaled.
    Observed Generation:   1
    Reason:                Successful
    Status:                True
    Type:                  Successful
  Observed Generation:     1
  Phase:                   Successful
Events:
  Type     Reason                                                  Age   From                         Message
  ----     ------                                                  ----  ----                         -------
  Normal   PauseDatabase                                           112s  KubeDB Ops-manager Operator  Pausing Elasticsearch demo/es
  Warning  create es client; ConditionStatus:True                  104s  KubeDB Ops-manager Operator  create es client; ConditionStatus:True
  Warning  get voting config exclusion; ConditionStatus:True       104s  KubeDB Ops-manager Operator  get voting config exclusion; ConditionStatus:True
  Warning  exclude node allocation; ConditionStatus:True           103s  KubeDB Ops-manager Operator  exclude node allocation; ConditionStatus:True
  Warning  get used data nodes; ConditionStatus:True               103s  KubeDB Ops-manager Operator  get used data nodes; ConditionStatus:True
  Warning  move data; ConditionStatus:True                         103s  KubeDB Ops-manager Operator  move data; ConditionStatus:True
  Warning  patch pet set; ConditionStatus:True                     103s  KubeDB Ops-manager Operator  patch pet set; ConditionStatus:True
  Warning  get pod; ConditionStatus:True                           99s   KubeDB Ops-manager Operator  get pod; ConditionStatus:True
  Warning  delete pvc; ConditionStatus:True                        99s   KubeDB Ops-manager Operator  delete pvc; ConditionStatus:True
  Warning  get pvc; ConditionStatus:False                          99s   KubeDB Ops-manager Operator  get pvc; ConditionStatus:False
  Warning  get pod; ConditionStatus:True                           94s   KubeDB Ops-manager Operator  get pod; ConditionStatus:True
  Warning  delete pvc; ConditionStatus:True                        94s   KubeDB Ops-manager Operator  delete pvc; ConditionStatus:True
  Warning  get pvc; ConditionStatus:True                           94s   KubeDB Ops-manager Operator  get pvc; ConditionStatus:True
  Warning  create es client; ConditionStatus:True                  89s   KubeDB Ops-manager Operator  create es client; ConditionStatus:True
  Warning  delete voting config exclusion; ConditionStatus:True    89s   KubeDB Ops-manager Operator  delete voting config exclusion; ConditionStatus:True
  Warning  delete node allocation exclusion; ConditionStatus:True  89s   KubeDB Ops-manager Operator  delete node allocation exclusion; ConditionStatus:True
  Normal   HorizontalScaleCombinedNode                             89s   KubeDB Ops-manager Operator  ScaleDown es nodes
  Normal   UpdateDatabase                                          83s   KubeDB Ops-manager Operator  successfully updated Elasticsearch CR
  Normal   ResumeDatabase                                          83s   KubeDB Ops-manager Operator  Resuming Elasticsearch demo/es
  Normal   ResumeDatabase                                          83s   KubeDB Ops-manager Operator  Successfully resumed Elasticsearch demo/es
  Normal   Successful                                              83s   KubeDB Ops-manager Operator  Successfully Horizontally Scaled Database

Now, we are going to verify the number of replicas this cluster has from the Elasticsearch object, number of pods the petset have,

$ kubectl get Elasticsearch -n demo es -o json | jq '.spec.replicas' 
2

$ kubectl get petset -n demo es -o json | jq '.spec.replicas'
2

From all the above outputs we can see that the replicas of the combined cluster is 2. That means we have successfully scaled down the replicas of the Elasticsearch combined cluster.

Cleaning Up

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

kubectl delete es -n demo es
kubectl delete Elasticsearchopsrequest -n demo esops-hscale-up-combined esops-hscale-down-combined
kubectl delete ns demo

Next Steps

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