Manage Elasticsearch with KubeBlocks

Elasticsearch is a distributed, RESTful search and analytics engine that is capable of solving an ever-growing number of use cases. As the heart of the Elastic Stack, Elasticsearch stores your data centrally, allowing you to search it quickly, tune relevancy, perform sophisticated analytics, and easily scale.

KubeBlocks supports the management of Elasticsearch. This tutorial illustrates how to create and manage an Elasticsearch cluster by kbcli, kubectl or a YAML file. You can find the YAML examples and guides in the GitHub repository.

Before you start

• Install kbcli if you want to manage your Elasticsearch cluster with kbcli.

• Install KubeBlocks by kbcli or by Helm.

• Install and enable the elasticsearch Addon by kbcli or by Helm.

• To keep things isolated, create a separate namespace called demo throughout this tutorial.

  kubectl create namespace demo

Create a cluster

kbcli

Steps

1. Execute the following command to create an Elasticsearch cluster.

   kbcli cluster create elasticsearch mycluster -n demo

note

If you want to customize your cluster specifications, kbcli provides various options, such as setting cluster version, termination policy, CPU, and memory. You can view these options by adding --help or -h flag.

kbcli cluster create elasticsearch --help

kbcli cluster create elasticsearch -h

2. Check whether the cluster is created.

   kbcli cluster list
   >
   NAME        NAMESPACE   CLUSTER-DEFINITION   VERSION   TERMINATION-POLICY   STATUS     CREATED-TIME
   mycluster   demo                                       Delete               Creating   Sep 27,2024 11:42 UTC+0800  

3. Check the cluster details.

   kbcli cluster describe elasticsearch -n demo

kubectl

KubeBlocks implements a Cluster CRD to define a cluster. Here is an example of creating an Elasticsearch cluster.

cat <<EOF | kubectl apply -f -
apiVersion: apps.kubeblocks.io/v1alpha1
kind: Cluster
metadata:
  annotations:
    kubeblocks.io/extra-env: '{"mdit-roles":"master,data,ingest,transform","mode":"multi-node"}'
  labels:
    app.kubernetes.io/instance: mycluster
    app.kubernetes.io/version: 8.8.2
    helm.sh/chart: elasticsearch-cluster-0.9.0
  name: mycluster
  namespace: demo
spec:
  affinity:
    podAntiAffinity: Required
    tenancy: SharedNode
    topologyKeys:
    - kubernetes.io/hostname
  componentSpecs:
  - componentDef: elasticsearch-8
    disableExporter: true
    name: mdit
    replicas: 3
    resources:
      limits:
        cpu: "1"
        memory: 2Gi
      requests:
        cpu: "1"
        memory: 2Gi
    serviceAccountName: kb-mycluster
    serviceVersion: 8.8.2
    services: null
    volumeClaimTemplates:
    - name: data
      spec:
        accessModes:
        - ReadWriteOnce
        resources:
          requests:
            storage: 20Gi
  terminationPolicy: Delete
EOF

Field	Definition
spec.terminationPolicy	It is the policy of cluster termination. The default value is Delete. Valid values are DoNotTerminate, Delete, WipeOut. For the detailed definition, you can refer to Termination Policy.
spec.affinity	It defines a set of node affinity scheduling rules for the cluster's Pods. This field helps control the placement of Pods on nodes within the cluster.
spec.affinity.podAntiAffinity	It specifies the anti-affinity level of Pods within a component. It determines how pods should spread across nodes to improve availability and performance.
spec.affinity.topologyKeys	It represents the key of node labels used to define the topology domain for Pod anti-affinity and Pod spread constraints.
spec.tolerations	It is an array that specifies tolerations attached to the cluster's Pods, allowing them to be scheduled onto nodes with matching taints.
spec.componentSpecs	It is the list of components that define the cluster components. This field allows customized configuration of each component within a cluster.
spec.componentSpecs.componentDefRef	It is the name of the component definition that is defined in the cluster definition and you can get the component definition names with kubectl get clusterdefinition elasticsearch -o json \| jq '.spec.componentDefs[].name'.
spec.componentSpecs.name	It specifies the name of the component.
spec.componentSpecs.disableExporter	It defines whether the monitoring function is enabled.
spec.componentSpecs.replicas	It specifies the number of replicas of the component.
spec.componentSpecs.resources	It specifies the resource requirements of the component.

KubeBlocks operator watches for the Cluster CRD and creates the cluster and all dependent resources. You can get all the resources created by the cluster with kubectl get all,secret,rolebinding,serviceaccount -l app.kubernetes.io/instance=mycluster -n demo.

kubectl get all,secret,rolebinding,serviceaccount -l app.kubernetes.io/instance=mycluster -n demo

Run the following command to see the created Elasticsearch cluster object:

kubectl get cluster mycluster -n demo -o yaml

Connect to the Elasticsearch cluster

Elasticsearch provides the HTTP protocol for client access on port 9200. You can visit the cluster by the local host.

curl http://127.0.0.1:9200/_cat/nodes?v

Monitor the Elasticsearch cluster

The monitoring function of Elasticsearch is the same as other engines. For details, refer to the monitoring tutorial.

Scale

KubeBlocks supports horizontally and vertially scaling an Elasticsearch cluster.

Before you start

Check whether the cluster status is Running. Otherwise, the following operations may fail.

kbcli

kbcli cluster list mycluster -n demo
>
NAME        NAMESPACE   CLUSTER-DEFINITION   VERSION           TERMINATION-POLICY   STATUS    CREATED-TIME
mycluster   demo                                               Delete               Running   Sep 27,2024 11:42 UTC+0800

kubectl

kubectl get cluster mycluster -n demo
>
NAME        CLUSTER-DEFINITION   VERSION                  TERMINATION-POLICY   STATUS    AGE
mycluster                                                 Delete               Running   4m29s

Scale horizontally

Horizontal scaling changes the amount of pods. For example, you can scale out replicas from three to five.

From v0.9.0, besides replicas, KubeBlocks also supports scaling in and out instances, refer to the Horizontal Scale tutorial for more details and examples.

kbcli

1. Set the --replicas value according to your needs and perform the horizontal scaling.

   kbcli cluster hscale mycluster --replicas=2 --components=elasticsearch -n demo
   • --components describes the component name ready for horizontal scaling.
   • --replicas describes the replica amount of the specified components. Edit the amount based on your demands to scale in or out replicas.

   Please wait a few seconds until the scaling process is over.

2. Validate the horizontal scaling operation.

   • View the OpsRequest progress.

     KubeBlocks outputs a command automatically for you to view the OpsRequest progress. The output includes the status of this OpsRequest and Pods. When the status is Succeed, this OpsRequest is completed.

     kbcli cluster describe-ops mycluster-horizontalscaling-xpdwz -n demo

   • View the cluster satus.

     kbcli cluster list mycluster -n demo
     >
     NAME        NAMESPACE   CLUSTER-DEFINITION   VERSION           TERMINATION-POLICY   STATUS     CREATED-TIME
     mycluster   demo                                               Delete               Updating   Sep 27,2024 10:01 UTC+0800
     • STATUS=Updating: it means horizontal scaling is in progress.
     • STATUS=Running: it means horizontal scaling has been applied.

3. After the OpsRequest status is Succeed or the cluster status is Running again, check whether the corresponding resources change.

   kbcli cluster describe mycluster -n demo

OpsRequest

1. Apply an OpsRequest to a specified cluster. Configure the parameters according to your needs.

   The example below means adding two replicas.

   kubectl apply -f - <<EOF
   >
   apiVersion: apps.kubeblocks.io/v1alpha1
   kind: OpsRequest
   metadata:
     name: ops-horizontal-scaling
     namespace: demo
   spec:
     clusterName: mycluster
     type: HorizontalScaling
     horizontalScaling:
     - componentName: elasticsearch
       scaleOut:
         replicaChanges: 2
   EOF

   If you want to scale in replicas, replace scaleOut with scaleIn.

   The example below means deleting two replicas.

   kubectl apply -f - <<EOF
   >
   apiVersion: apps.kubeblocks.io/v1alpha1
   kind: OpsRequest
   metadata:
     name: ops-horizontal-scaling
     namespace: demo
   spec:
     clusterName: mycluster
     type: HorizontalScaling
     horizontalScaling:
     - componentName: elasticsearch
       scaleIn:
         replicaChanges: 2
   EOF

2. Check the operation status to validate the horizontal scaling.

   kubectl get ops -n demo
   >
   NAMESPACE   NAME                     TYPE                CLUSTER     STATUS    PROGRESS   AGE
   demo        ops-horizontal-scaling   HorizontalScaling   mycluster   Succeed   3/3        6m

   If an error occurs, you can troubleshoot with kubectl describe ops -n demo command to view the events of this operation.

3. Check whether the corresponding resources change.

   kubectl describe cluster mycluster -n demo

Edit cluster YAML file

1. Change the configuration of spec.componentSpecs.replicas in the YAML file. spec.componentSpecs.replicas stands for the pod amount and changing this value triggers a horizontal scaling of a cluster.

   kubectl edit cluster mycluster -n demo
   >
   apiVersion: apps.kubeblocks.io/v1alpha1
   kind: Cluster
   metadata:
     name: mycluster
     namespace: demo
   spec:
     componentSpecs:
     - name: mdit
       componentDefRef: elasticsearch
       replicas: 1 # Change the amount
       volumeClaimTemplates:
       - name: data
         spec:
           accessModes:
             - ReadWriteOnce
           resources:
             requests:
               storage: 1Gi
    terminationPolicy: Delete

2. Check whether the corresponding resources change.

   kubectl describe cluster mycluster -n demo

Scale vertically

kbcli

1. Set the --cpu and --memory values according to your needs and run the following command to perform vertical scaling.

   kbcli cluster vscale mycluster --cpu=2 --memory=3Gi --components=elasticsearch -n demo

   Please wait a few seconds until the scaling process is over.

2. Validate the vertical scaling operation.

   • View the OpsRequest progress.

     KubeBlocks outputs a command automatically for you to view the OpsRequest progress. The output includes the status of this OpsRequest and Pods. When the status is Succeed, this OpsRequest is completed.

     kbcli cluster describe-ops mycluster-verticalscaling-rpw2l -n demo

   • Check the cluster status.

     kbcli cluster list mycluster -n demo
     >
     NAME        NAMESPACE   CLUSTER-DEFINITION   VERSION           TERMINATION-POLICY   STATUS     CREATED-TIME
     mycluster   demo                                               Delete               Updating   Sep 27,2024 10:01 UTC+0800

     • STATUS=Updating: it means the vertical scaling is in progress.

     • STATUS=Running: it means the vertical scaling operation has been applied.

     • STATUS=Abnormal: it means the vertical scaling is abnormal. The reason may be that the number of the normal instances is less than that of the total instance or the leader instance is running properly while others are abnormal.

       To solve the problem, you can manually check whether this error is caused by insufficient resources. Then if AutoScaling is supported by the Kubernetes cluster, the system recovers when there are enough resources. Otherwise, you can create enough resources and troubleshoot with kubectl describe command.

3. After the OpsRequest status is Succeed or the cluster status is Running again, check whether the corresponding resources change.

   kbcli cluster describe mycluster -n demo

OpsRequest

1. Apply an OpsRequest to a specified cluster. Configure the parameters according to your needs.

   apiVersion: apps.kubeblocks.io/v1alpha1
   kind: OpsRequest
   metadata:
     name: elasticsearch-verticalscaling
     namespace: demo
   spec:
     clusterName: mycluster
     type: VerticalScaling
     verticalScaling:
     - componentName: mdit
       requests:
         cpu: '1'
         memory: '3Gi'
       limits:
         cpu: '1'
         memory: '3Gi'

2. Check the operation status to validate the horizontal scaling.

   kubectl get ops -n demo
   >
   NAMESPACE   NAME                     TYPE                CLUSTER     STATUS    PROGRESS   AGE
   demo        ops-horizontal-scaling   HorizontalScaling   mycluster   Succeed   3/3        6m

   If an error occurs, you can troubleshoot with kubectl describe ops -n demo command to view the events of this operation.

3. Check whether the corresponding resources change.

   kubectl describe cluster mycluster -n demo

Edit cluster YAML file

1. Change the configuration of spec.componentSpecs.resources in the YAML file. spec.componentSpecs.resources controls the requirement and limit of resources and changing them triggers a vertical scaling.

   kubectl edit cluster mycluster -n demo
   >
   apiVersion: apps.kubeblocks.io/v1alpha1
   kind: Cluster
   metadata:
     name: mycluster
     namespace: demo
   spec:
     terminationPolicy: Delete
     affinity:
       podAntiAffinity: Preferred
       topologyKeys:
       - kubernetes.io/hostname
       tenancy: SharedNode
     tolerations:
     - key: kb-data
       operator: Equal
       value: 'true'
       effect: NoSchedule
     componentSpecs:
     - name: mdit
       componentDef: elasticsearch
       serviceAccountName: null
       disableExporter: true
       replicas: 1
       resources:
         limits:
           cpu: '1'
           memory: 4Gi
         requests:
           cpu: '1'
           memory: 4Gi

2. Check whether the corresponding resources change.

   kubectl describe cluster mycluster -n demo

Volume Expansion

Before you start

Check whether the cluster status is Running. Otherwise, the following operations may fail.

kbcli

kbcli cluster list mycluster -n demo
>
NAME        NAMESPACE   CLUSTER-DEFINITION   VERSION           TERMINATION-POLICY   STATUS    CREATED-TIME
mycluster   demo                                               Delete               Running   Sep 27,2024 11:42 UTC+0800

kubectl

kubectl get cluster mycluster -n demo
>
NAME        CLUSTER-DEFINITION   VERSION                  TERMINATION-POLICY   STATUS    AGE
mycluster                                                 Delete               Running   4m29s

Steps

kbcli

1. Set the --storage value according to your need and run the command to expand the volume.

   kbcli cluster volume-expand mycluster --storage=40Gi --components=elasticsearch -t data -n demo

   The volume expansion may take a few minutes.

2. Validate the volume expansion operation.

   • View the OpsRequest progress.

     KubeBlocks outputs a command automatically for you to view the details of the OpsRequest progress. The output includes the status of this OpsRequest and PVC. When the status is Succeed, this OpsRequest is completed.

     kbcli cluster describe-ops mycluster-volumeexpansion-5pbd2 -n demo

   • View the cluster status.

     kbcli cluster list mycluster
     >
     NAME        NAMESPACE   CLUSTER-DEFINITION   VERSION           TERMINATION-POLICY   STATUS     CREATED-TIME
     mycluster   demo                                               Delete               Updating   Sep 27,2024 10:01 UTC+0800
     • STATUS=Updating: it means the volume expansion is in progress.
     • STATUS=Running: it means the volume expansion operation has been applied.

3. After the OpsRequest status is Succeed or the cluster status is Running again, check whether the corresponding resources change.

   kbcli cluster describe mycluster -n demo

OpsRequest

1. Change the value of storage according to your need and run the command below to expand the volume of a cluster.

   kubectl apply -f - <<EOF
   apiVersion: apps.kubeblocks.io/v1alpha1
   kind: OpsRequest
   metadata:
     name: ops-volume-expansion
     namespace: demo
   spec:
     clusterName: mycluster
     type: VolumeExpansion
     volumeExpansion:
     - componentName: elasticsearch
       volumeClaimTemplates:
       - name: data
         storage: "40Gi"
   EOF

2. Validate the volume expansion operation.

   kubectl get ops -n demo
   >
   NAMESPACE   NAME                   TYPE              CLUSTER     STATUS    PROGRESS   AGE
   demo        ops-volume-expansion   VolumeExpansion   mycluster   Succeed   3/3        6m

   If an error occurs, you can troubleshoot with kubectl describe ops -n demo command to view the events of this operation.

3. Check whether the corresponding cluster resources change.

   kubectl describe cluster mycluster -n demo

Edit cluster YAML file

1. Change the value of spec.componentSpecs.volumeClaimTemplates.spec.resources in the cluster YAML file.

   spec.componentSpecs.volumeClaimTemplates.spec.resources is the storage resource information of the pod and changing this value triggers the volume expansion of a cluster.

   kubectl edit cluster mycluster -n demo
   apiVersion: apps.kubeblocks.io/v1alpha1
   kind: Cluster
   metadata:
     name: mycluster
     namespace: demo
   spec:
     componentSpecs:
     - name: mdit
       componentDefRef: elasticsearch
       replicas: 2
       volumeClaimTemplates:
       - name: data
         spec:
           accessModes:
             - ReadWriteOnce
           resources:
             requests:
               storage: 40Gi # Change the volume storage size.
     terminationPolicy: Delete

2. Check whether the corresponding cluster resources change.

   kubectl describe cluster mycluster -n demo

Stop/Start a cluster

You can stop/start a cluster to save computing resources. When a cluster is stopped, the computing resources of this cluster are released, which means the pods of Kubernetes are released, but the storage resources are reserved. Start this cluster again if you want to restore the cluster resources from the original storage by snapshots.

Stop a cluster

1. Configure the name of your cluster and run the command below to stop this cluster.

   kbcli

   kbcli cluster stop mycluster -n demo

   OpsRequest

   Configure replicas as 0 to delete pods.

   kubectl apply -f - <<EOF
   apiVersion: apps.kubeblocks.io/v1alpha1
   kind: OpsRequest
   metadata:
     name: ops-stop
     namespace: demo
   spec:
     clusterName: mycluster
     type: Stop
   EOF

   Edit cluster YAML file

   Edit the cluster YAML file and configure replicas as 0 to delete pods.

   kubectl edit cluster mycluster -n demo
   >
   apiVersion: apps.kubeblocks.io/v1alpha1
   kind: Cluster
   metadata:
       name: mycluster
       namespace: demo
   spec:
     terminationPolicy: Delete
     componentSpecs:
     - name: mdit
       componentDefRef: elasticsearch
       disableExporter: true  
       replicas: 0
       volumeClaimTemplates:
       - name: data
         spec:
           storageClassName: standard
           accessModes:
             - ReadWriteOnce
           resources:
             requests:
               storage: 20Gi

2. Check the status of the cluster to see whether it is stopped.

   kbcli

   kbcli cluster list mycluster -n demo

   kubectl

   kubectl get cluster mycluster -n demo

Start a cluster

1. Configure the name of your cluster and run the command below to start this cluster.

   kbcli

   kbcli cluster start mycluster -n demo

   OpsRequest

   Run the command below to start a cluster.

   kubectl apply -f - <<EOF
   apiVersion: apps.kubeblocks.io/v1alpha1
   kind: OpsRequest
   metadata:
     name: ops-start
     namespace: demo
   spec:
     clusterName: mycluster
     type: Start
   EOF 

   Edit cluster YAML file

   Change replicas back to the original amount to start this cluster again.

   kubectl edit cluster mycluster -n demo
   >
   apiVersion: apps.kubeblocks.io/v1alpha1
   kind: Cluster
   metadata:
       name: mycluster
       namespace: demo
   spec:
     terminationPolicy: Delete
     componentSpecs:
     - name: mdit
       componentDefRef: elasticsearch
       disableExporter: true  
       replicas: 1
       volumeClaimTemplates:
       - name: data
         spec:
           storageClassName: standard
           accessModes:
             - ReadWriteOnce
           resources:
             requests:
               storage: 20Gi

2. Check the status of the cluster to see whether it is running again.

   kbcli

   kbcli cluster list mycluster -n demo

   kubectl

   kubectl get cluster mycluster -n demo

Restart

kbcli

1. Restart a cluster.

   Configure the values of components and ttlSecondsAfterSucceed and run the command below to restart a specified cluster.

   kbcli cluster restart mycluster -n demo --components="elasticsearch" --ttlSecondsAfterSucceed=30
   • components describes the component name that needs to be restarted.
   • ttlSecondsAfterSucceed describes the time to live of an OpsRequest job after the restarting succeeds.

2. Validate the restarting.

   Run the command below to check the cluster status to check the restarting status.

   kbcli cluster list mycluster -n demo
   >
   NAME            CLUSTER-DEFINITION          VERSION               TERMINATION-POLICY   STATUS    CREATED-TIME
   mycluster                                                         Delete               Running   Jul 05,2024 17:51 UTC+0800
   • STATUS=Updating: it means the cluster restart is in progress.
   • STATUS=Running: it means the cluster has been restarted.

OpsRequest

1. Restart a cluster.

   kubectl apply -f - <<EOF
   apiVersion: apps.kubeblocks.io/v1alpha1
   kind: OpsRequest
   metadata:
     name: ops-restart
     namespace: demo
   spec:
     clusterName: mycluster
     type: Restart 
     restart:
     - componentName: elasticsearch
   EOF

2. Check the pod and operation status to validate the restarting.

   kubectl get pod -n demo
   
   kubectl get ops ops-restart -n demo

   During the restarting process, there are two status types for pods.

   • STATUS=Terminating: it means the cluster restart is in progress.
   • STATUS=Running: it means the cluster has been restarted.

Delete a cluster

Termination policy

note

The termination policy determines how a cluster is deleted.

terminationPolicy	Deleting Operation
DoNotTerminate	DoNotTerminate blocks delete operation.
Halt	Halt deletes Cluster resources like Pods and Services but retains Persistent Volume Claims (PVCs), allowing for data preservation while stopping other operations. Halt policy is deprecated in v0.9.1 and will have same meaning as DoNotTerminate.
Delete	Delete extends the Halt policy by also removing PVCs, leading to a thorough cleanup while removing all persistent data.
WipeOut	WipeOut deletes all Cluster resources, including volume snapshots and backups in external storage. This results in complete data removal and should be used cautiously, especially in non-production environments, to avoid irreversible data loss.

To check the termination policy, execute the following command.

kbcli

kbcli cluster list mycluster -n demo
>
NAME        NAMESPACE   CLUSTER-DEFINITION   VERSION           TERMINATION-POLICY   STATUS    CREATED-TIME
mycluster   demo                                               Delete               Running   Sep 27,2024 11:42 UTC+0800

kubectl

kubectl get cluster mycluster -n demo
>
NAME     CLUSTER-DEFINITION   VERSION   TERMINATION-POLICY   STATUS     AGE
mydemo                                  Delete               Creating   27m

Steps

Run the command below to delete a specified cluster.

kbcli

kbcli cluster delete mycluster -n demo

kubectl

If you want to delete a cluster and its all related resources, you can modify the termination policy to WipeOut, then delete the cluster.

kubectl patch -n demo cluster mycluster -p '{"spec":{"terminationPolicy":"WipeOut"}}' --type="merge"

kubectl delete -n demo cluster mycluster