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This artical explains how to set custom variables using the Kubernetes operator. custom variables are nothing but additional properties specified in HiveMQCluster specification.

With the help of operator.templateConfigMap and controllerTemplate we can set custom variables.

Let's take the example of setting custom annotations with help of a custom variable.

Instructions

1. Generate default operator templates for configMap using the following steps.

   • Code Block
     language bash
     $ helm template -s templates/hivemq-operator/operator-templates.yaml hivemq hivemq/hivemq-operator >> custom-template.yaml

2. Edit the custom-template.yaml to incorporate your changes which was generated by step 1

   • Code Block

     apiVersion: v1 kind: ConfigMap metadata: name: <your custom template name> data: cluster-daemon-set.yaml: |- ... cluster-deployment.yaml: |- apiVersion: apps/v1 kind: Deployment metadata: name: "{{ spec.name }}" namespace: "{{ spec.namespace }}" ... spec: minReadySeconds: 30 ... template: metadata: labels: app: "hivemq" hivemq-cluster: "{{ spec.name }}" hivemq.com/node-offline: "false" annotations: mycustomValue: "{{ spec.customProperties.myCustomProperty }}"

3. Apply the config map by using the following command

   • Code Block
     $ kubectl apply -f <your custom template yaml filename>

4. Set templateConfigMap config in values.yaml of Kubernetes operator

   • Code Block
     operator: deployCr: false templateConfigMap: <configmap name you created in step3 > ...

5. Execute helm upgrade / install the operator with the following command.

   • Code Block
     $ helm upgrade --install -f values.yaml <cluster name> hivemq/hivemq-operator

6. Add custom controller template in HiveMQ cluster yaml. This will refer to the custom template which was created and configured in step 1 and step 2 respectively.

   • Code Block
     apiVersion: hivemq.com/v1 kind: HiveMQCluster metadata: name: hivemq-cluster spec: controllerTemplate: "cluster-deployment.yaml" customProperties: myCustomProperty: "testvalue" ...

7. Deploy HiveMQ cluster with the following command

   • Code Block
     $ kubectl apply -f < hivemq cluster.yaml

8. You can check your changes are applied correctly or not by executing the following command

   • Code Block
     $ kubectl get pods $ kubectl describe pod <one of running pod name>

     
     The output of the describe command will include changes.
     Please refer following output as an example.

     Code Block
     Name: hivemq-cluster1123-6fd545799f-4xnc5 Namespace: XXXXX Priority: 0 Node: node11/10.2.1.218 Start Time: Mon, 31 May 2021 11:39:10 +0200 Labels: app=hivemq hivemq-cluster=hivemq-cluster1123 hivemq.com/node-offline=false pod-template-hash=6fd545799f Annotations: mycustomValue: test123 Status: Running ...

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