Enable Persistence In EMQX Cluster

Task Target

Configure EMQX 4.x cluster persistence through persistent field.
Configure EMQX 5.x cluster Core node persistence through volumeClaimTemplates field.

Configure EMQX Cluster Persistence

The following is the relevant configuration of EMQX Custom Resource. You can choose the corresponding APIVersion according to the version of EMQX you want to deploy. For the specific compatibility relationship, please refer to EMQX Operator Compatibility:

apps.emqx.io/v2beta1 EMQX supports configuration of EMQX cluster Core node persistence through .spec.coreTemplate.spec.volumeClaimTemplates field. The semantics and configuration of .spec.coreTemplate.spec.volumeClaimTemplates field are consistent with PersistentVolumeClaimSpec of Kubernetes, and its configuration can refer to the document: PersistentVolumeClaimSpec.

When the user configures the .spec.coreTemplate.spec.volumeClaimTemplates field, EMQX Operator will mount the /opt/emqx/data directory in the EMQX container to StorageClass in the PV and PVC created, when the EMQX Pod is deleted, the PV and PVC will not be deleted, so as to achieve the purpose of saving EMQX runtime data. For more information about PV and PVC, refer to the document Persistent Volumes.

Save the following content as a YAML file and deploy it via the kubectl apply command

yaml

apiVersion: apps.emqx.io/v2beta1
kind: EMQX
metadata:
  name: emqx
spec:
  image: emqx:5.1
  coreTemplate:
    spec:
      volumeClaimTemplates:
        storageClassName: standard
        resources:
          requests:
            storage: 20Mi
        accessModes:
          - ReadWriteOnce
      replicas: 3
  listenersServiceTemplate:
    spec:
      type: LoadBalancer
  dashboardServiceTemplate:
    spec:
      type: LoadBalancer

storageClassName field indicates the name of the StorageClass. You can use the command kubectl get storageclass to get the StorageClass that already exists in the Kubernetes cluster, or you can create a StorageClass according to your own needs.

Wait for EMQX cluster to be ready, you can check the status of the EMQX cluster through kubectl get command, please make sure STATUS is Running, this may take some time
bash
```
$ kubectl get emqx emqx
NAME   IMAGE      STATUS    AGE
emqx   emqx:5.1   Running   10m
```
Obtain the Dashboard External IP of the EMQX cluster and access the EMQX console
EMQX Operator will create two EMQX Service resources, one is emqx-dashboard and the other is emqx-listeners, corresponding to EMQX console and EMQX listening port respectively.
bash
```
$ kubectl get svc emqx-dashboard -o json | jq '.status.loadBalancer.ingress[0].ip'

192.168.1.200
```
Access http://192.168.1.200:18083 through a browser, and use the default username and password admin/public to login EMQX console.

apps.emqx.io/v1beta4 EmqxEnterprise supports configuring EMQX cluster persistence through the .spec.persistent field. The semantics and configuration of the .spec.persistent field are consistent with PersistentVolumeClaimSpec of Kubernetes, and its configuration can refer to the document: PersistentVolumeClaimSpec.

When the user configures the .spec.persistent field, EMQX Operator will mount the /opt/emqx/data directory in the EMQX container to StorageClass in the PV and PVC created, when the EMQX Pod is deleted, the PV and PVC will not be deleted, so as to achieve the purpose of saving EMQX runtime data. For more information about PV and PVC, refer to the document Persistent Volumes.

Save the following content as a YAML file and deploy it via the kubectl apply command

yaml

apiVersion: apps.emqx.io/v1beta4
kind: EmqxEnterprise
metadata:
  name: emqx-ee
spec:
  persistent:
    metadata:
      name: emqx-ee
    spec:
      storageClassName: standard
      resources:
        requests:
          storage: 20Mi
      accessModes:
        - ReadWriteOnce
  template:
    spec:
      emqxContainer:
        image:
          repository: emqx/emqx-ee
          version: 4.4.14
  serviceTemplate:
    spec:
      type: LoadBalancer

The storageClassName field indicates the name of the StorageClass. You can use the command kubectl get storageclass to get the StorageClass that already exists in the Kubernetes cluster, or you can create a StorageClass according to your own needs.

Wait for the EMQX cluster to be ready, you can check the status of the EMQX cluster through kubectl get command, please make sure STATUS is Running, this may take some time
bash
```
$ kubectl get emqxenterprises
NAME      STATUS   AGE
emqx-ee   Running  8m33s
```
Obtain the External IP of EMQX cluster and access EMQX console
bash
```
$ kubectl get svc emqx-ee -o json | jq '.status.loadBalancer.ingress[0].ip'

192.168.1.200
```
Access http://192.168.1.200:18083 through a browser, and use the default username and password admin/public to login EMQX console.

Verify EMQX Cluster Persistence

TIP

The screenshots of the Dashboard below are from EMQX 5, EMQX 4 Dashboard also supports the corresponding function, please operate by yourself.

Verification scheme: 1) Passed in the old EMQX Dashboard creates a test rule; 2) Deletes the old cluster; 3) Recreates the EMQX cluster,and checks whether the previously created rule exists through the Dashboard.

Access EMQX Dashboard through browser to create test rules
bash
external_ip=$(kubectl get svc emqx-listeners -o json | jq '.status.loadBalancer.ingress[0].ip')
bash
external_ip=$(kubectl get svc emqx-ee -o json | jq '.status.loadBalancer.ingress[0].ip')
Login EMQX Dashboard by accessing http://${external_ip}:18083, and click Data Integration → Rules to enter the page for creating rules. Let’s first click the button to add an action Add a response action for this rule, and then click Create to generate a rule, as shown in the following figure:
When our rule is successfully created, a rule record will appear on the page with the rule ID: emqx-persistent-test, as shown in the figure below:
delete old EMQX cluster
Execute the following command to delete the EMQX cluster:
bash
```
$ kubectl delete -f emqx.yaml

emqx.apps.emqx.io "emqx" deleted
# emqxenterprise.apps.emqx.io "emqx" deleted
```
emqx-persistent.yaml is the YAML file used to deploy the EMQX cluster for the first time in this article, and this file does not need to be changed.
Recreate the EMQX cluster
Execute the following command to recreate the EMQX cluster:
bash
```
$ kubectl apply -f emqx.yaml

emqx.apps.emqx.io/emqx created
# emqxenterprise.apps.emqx.io/emqx created
```
Wait for the EMQX cluster to be ready, and then access the EMQX Dashboard through the browser to check whether the previously created rules exist, as shown in the following figure:
It can be seen from the figure that the rule emqx-persistent-test created in the old cluster still exists in the new cluster, which means that the persistence we configured is in effect.

Enable Persistence In EMQX Cluster ​

Task Target ​

Configure EMQX Cluster Persistence ​

Verify EMQX Cluster Persistence ​

Enable Persistence In EMQX Cluster

Task Target

Configure EMQX Cluster Persistence

Verify EMQX Cluster Persistence