KubeBlocks
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Manage RabbitMQ with KubeBlocks
  1. Before you start
  2. Create a cluster
  3. Connect to the cluster
  4. Scale
    1. Scale vertically
      1. Steps
    2. Scale horizontally
      1. Steps
  5. Volume expansion
  6. Restart
  7. Stop/Start a cluster
    1. Stop a cluster
    2. Start a cluster
  8. Delete a cluster
    1. Termination policy
    2. Steps

Manage RabbitMQ with KubeBlocks

RabbitMQ is a reliable and mature messaging and streaming broker, which is easy to deploy on cloud environments, on-premises, and on your local machine.

KubeBlocks supports the management of RabbitMQ.

NOTE

Currently, KubeBlocks only supports managing RabbitMQ by kubectl.

Before you start

  • Install KubeBlocks.
  • Install and enable the rabbitmq addon.

Create a cluster

KubeBlocks implements a Cluster CRD to define a cluster. Here is an example of creating a RabbitMQ cluster with three replicas. Pods are distributed on different nodes by default. But if you only have one node for a cluster with three replicas, set spec.affinity.topologyKeys as null.

cat <<EOF | kubectl apply -f -
apiVersion: apps.kubeblocks.io/v1alpha1
kind: Cluster
metadata:
  name: mycluster
  namespace: demo
  labels:
    helm.sh/chart: rabbitmq-cluster-0.9.0
    app.kubernetes.io/version: "3.13.2"
    app.kubernetes.io/instance: mycluster
spec:
  terminationPolicy: Delete
  affinity:
    podAntiAffinity: Preferred
    topologyKeys:
      - kubernetes.io/hostname
  componentSpecs:
    - name: rabbitmq
      componentDef: rabbitmq
      serviceVersion: 3.13.2
      replicas: 3
      serviceAccountName: kb-mycluster
      resources:
        limits:
          cpu: "0.5"
          memory: "0.5Gi"
        requests:
          cpu: "0.5"
          memory: "0.5Gi"
      volumeClaimTemplates:
        - name: data # ref clusterDefinition components.containers.volumeMounts.name
          spec:
            accessModes:
              - ReadWriteOnce
            resources:
              requests:
                storage: 20Gi
      services:
EOF
FieldDefinition
spec.terminationPolicyIt 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.affinityIt 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.podAntiAffinityIt 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.topologyKeysIt represents the key of node labels used to define the topology domain for Pod anti-affinity and Pod spread constraints.
spec.componentSpecsIt is the list of components that define the cluster components. This field allows customized configuration of each component within a cluster.
spec.componentSpecs.componentDefRefIt 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 qdrant -o json | jq '.spec.componentDefs[].name'.
spec.componentSpecs.nameIt specifies the name of the component.
spec.componentSpecs.disableExporterIt defines whether the monitoring function is enabled.
spec.componentSpecs.replicasIt specifies the number of replicas of the component.
spec.componentSpecs.resourcesIt 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 RabbitMQ cluster object:

kubectl get cluster mycluster -n demo -o yaml

Connect to the cluster

Use the RabbitMQ tools to connect to and manage the RabbitMQ cluster.

Scale

Scale vertically

Before you start, check whether the cluster status is Running. Otherwise, the following operations may fail.

kubectl get cluster mycluster -n demo
>
NAME        CLUSTER-DEFINITION    VERSION        TERMINATION-POLICY     STATUS    AGE
mycluster                                        Delete                 Running   47m

Steps

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

    kubectl apply -f - <<EOF
apiVersion: apps.kubeblocks.io/v1alpha1
kind: OpsRequest
metadata:
  name: ops-vertical-scaling
  namespace: demo
spec:
  clusterName: mycluster
  type: VerticalScaling
  verticalScaling:
  - componentName: rabbitmq
    requests:
      memory: "2Gi"
      cpu: "1"
    limits:
      memory: "4Gi"
      cpu: "2"
EOF

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

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

    If an error occurs, you can troubleshoot it 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

  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.

    apiVersion: apps.kubeblocks.io/v1alpha1
kind: Cluster
metadata:
  name: mycluster
  namespace: demo
spec:
  componentSpecs:
  - name: rabbitmq
    componentDefRef: rabbitmq
    replicas: 3
    resources: # Change the values of resources
      requests:
        memory: "2Gi"
        cpu: "1"
      limits:
        memory: "4Gi"
        cpu: "2"
    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 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.

Before you start, check whether the cluster status is Running. Otherwise, the following operations may fail.

kubectl get cluster mycluster -n demo
>
NAME        CLUSTER-DEFINITION    VERSION        TERMINATION-POLICY     STATUS    AGE
mycluster                                        Delete                 Running   47m

Steps

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

    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: rabbitmq
    scaleIn:
      replicaChanges: 2
EOF

    If you want to scale in replicas, replace scaleOut with scaleIn and change the value in replicaChanges.

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

    kubectl get ops -n demo
>
NAME                     TYPE                CLUSTER     STATUS    PROGRESS   AGE
ops-horizontal-scaling   HorizontalScaling   mycluster   Succeed   2/2        6m

    If an error occurs, you can troubleshoot it 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

  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

    Edit the value of spec.componentSpecs.replicas.

    ...
spec:
  componentSpecs:
  - name: rabbitmq
    componentDefRef: rabbitmq
    replicas: 1 # Change this value
...

  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.

kubectl get cluster mycluster -n demo
>
NAME        CLUSTER-DEFINITION    VERSION        TERMINATION-POLICY     STATUS    AGE
mycluster                                        Delete                 Running   47m

  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: rabbitmq
    volumeClaimTemplates:
    - name: data
      storage: "40Gi"
EOF

  2. Validate the volume expansion operation.

    kubectl get ops -n demo
>
NAME                   TYPE              CLUSTER     STATUS    PROGRESS   AGE
ops-volume-expansion   VolumeExpansion   mycluster   Succeed   1/1        6m

    If an error occurs, you can troubleshoot it 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

  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

    Edit the value of spec.componentSpecs.volumeClaimTemplates.spec.resources.

    ...
spec:
  componentSpecs:
  - name: rabbitmq
    componentDefRef: rabbitmq
    replicas: 2
    volumeClaimTemplates:
    - name: data
      spec:
        accessModes:
          - ReadWriteOnce
        resources:
          requests:
            storage: 40Gi # Change the volume storage size
...

  2. Check whether the corresponding cluster resources change.

    kubectl describe cluster mycluster -n demo

Restart

  1. Restart a cluster.

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

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

    kubectl get pod -n demo

kubectl get ops -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.

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. You can start this cluster again by snapshots if you want to restore the cluster resources.

Stop a cluster

Run the command below to stop a cluster.

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

kubectl edit cluster mycluster -n demo

Configure replicas as 0 to delete pods.

kubectl edit cluster mycluster -n demo

Edit the value of replicas.

...
spec:
  terminationPolicy: Delete
  affinity:
    podAntiAffinity: Preferred
    topologyKeys:
      - kubernetes.io/hostname
  componentSpecs:
    - name: rabbitmq
      componentDef: rabbitmq
      serviceVersion: 3.13.2
      replicas: 0 # Change this value
...

Start a cluster

Run the command below to start a cluster.

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

kubectl edit cluster mycluster -n demo

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

kubectl edit cluster mycluster -n demo

Edit the value of replicas.

...
spec:
  terminationPolicy: Delete
  affinity:
    podAntiAffinity: Preferred
    topologyKeys:
      - kubernetes.io/hostname
  componentSpecs:
    - name: rabbitmq
      componentDef: rabbitmq
      serviceVersion: 3.13.2
      replicas: 3 # Change this value
...

Delete a cluster

Termination policy

NOTE

The termination policy determines how a cluster is deleted.

terminationPolicyDeleting Operation
DoNotTerminateDoNotTerminate blocks delete operation.
HaltHalt 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.
DeleteDelete extends the Halt policy by also removing PVCs, leading to a thorough cleanup while removing all persistent data.
WipeOutWipeOut 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.

kubectl get cluster mycluster -n demo
>
NAME        CLUSTER-DEFINITION    VERSION        TERMINATION-POLICY     STATUS    AGE
mycluster                                        Delete                 Running   55m

Steps

Run the command below to delete a specified cluster.

kubectl delete -n demo cluster mycluster

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

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