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Deploying a Couchbase Cluster Using the Operator

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      Prerequisites

      Before you attempt to deploy a Couchbase Server cluster with the Couchbase Autonomous Operator, ensure that you have done the following:

      • You have reviewed the prerequisites

      • You have deployed the admission controller and the Operator, and both are up and running

      • You have downloaded the Operator package

        The Operator package also contains YAML configuration files that will help you set up a Couchbase cluster.

      After you unpack the download, the resulting directory will be titled something like couchbase-autonomous-operator-kubernetes.x.x-linux_x86_64. Make sure to cd into this directory before you run the commands in this guide.

      Preparing the Couchbase Cluster Configuration

      To deploy a Couchbase Server cluster using the Operator, all you have to do is create a CouchbaseCluster configuration file that describes what you want the cluster to look like (e.g. number of nodes, types of services, system resources, etc), and then push that configuration file into Kubernetes. Like all Kubernetes configurations, a CouchbaseCluster is defined using either YAML or JSON (YAML is preferred by Kubernetes).

      The Operator package contains an example CouchbaseCluster configuration file (couchbase-cluster.yaml), also listed here:

      Example CouchbaseCluster Configuration for open source Kubernetes (couchbase-cluster.yaml)
      apiVersion: couchbase.com/v1
      kind: CouchbaseCluster
      metadata:
        name: cb-example
      spec:
        baseImage: couchbase/server
        version: enterprise-6.0.1
        authSecret: cb-example-auth
        exposeAdminConsole: true
        adminConsoleServices:
          - data
        cluster:
          dataServiceMemoryQuota: 256
          indexServiceMemoryQuota: 256
          searchServiceMemoryQuota: 256
          eventingServiceMemoryQuota: 256
          analyticsServiceMemoryQuota: 1024
          indexStorageSetting: memory_optimized
          autoFailoverTimeout: 120
          autoFailoverMaxCount: 3
          autoFailoverOnDataDiskIssues: true
          autoFailoverOnDataDiskIssuesTimePeriod: 120
          autoFailoverServerGroup: false
        buckets:
          - name: default
            type: couchbase
            memoryQuota: 128
            replicas: 1
            ioPriority: high
            evictionPolicy: fullEviction
            conflictResolution: seqno
            enableFlush: true
            enableIndexReplica: false
        servers:
          - size: 3
            name: all_services
            services:
              - data
              - index
              - query
              - search
              - eventing
              - analytics

      By taking a quick look at this configuration file, you can see that it defines a cluster by specifying the following:

      • Cluster name: cb-example (metadata.name)

      • Couchbase version: enterprise-6.0.1 (spec.version)

      • Buckets: 1 bucket named default (spec.buckets)

      • Size: 3 node cluster with all services on each node (spec.servers)

      • Secret: cb-example-auth (authSecret)

      You can use this example CouchbaseCluster configuration file "as-is" to test out how the Operator deploys a Couchbase Server cluster. However, to deploy a Couchbase cluster that is more specifically tailored to your development and production needs, you need to create your own custom configuration file that conforms to the CouchbaseCluster specification.

      Ensure that your Kubernetes environment has the appropriate resources for the Couchbase cluster that you’re trying to deploy.

      In the case of Minikube and Minishift, the default memory allocation is 2 GB. This is not sufficient for running a three-node Couchbase cluster like the one in the example configuration. If you’re using the example configuration for demo purposes, you should set the memory allocation to 4 GB at a minimum (8 GB recommended). You should also increase the CPU allocation if you experience poor performance.

      You can set the recommended memory and CPU allocation when you start Minikube or Minishift:

      minikube start --cpus 2 --memory 8192
      minishift start --cpus 2 --memory 8192

      About the authSecret Field

      One thing that’s important to note is the authSecret field. The Operator uses Kubernetes Secrets to create and manage the Couchbase super-user credentials. As a result, the authSecret field must refer to a secret that contains both a user name and a password field.

      For convenience, a sample secret is provided in the Operator package. When you push it to your Kubernetes cluster, the secret sets the user name to Administrator and the password to password.

      To push the secret into your Kubernetes cluster, run the following command:

      • Kubernetes

      • OpenShift

      kubectl create -f secret.yaml
      oc create -f secret.yaml

      Deploying the Couchbase Cluster

      The next step after creating the CouchbaseCluster configuration file is to push it to Kubernetes. To push the configuration, run the following command:

      • Kubernetes

      • OpenShift

      kubectl create -f couchbase-cluster.yaml
      oc create -f couchbase-cluster.yaml

      After receiving the configuration, the Operator automatically begins creating the cluster. The amount of time it takes to create the cluster depends on the configuration. You can track the progress of cluster creation using the kubectl describe command.

      Verifying the Deployment

      Once the cluster has been provisioned, you’ll see that various pods, a service, and a Couchbase cluster have been created. If you used the example configuration (which calls for a three-node cluster) you should see three pods created. The Operator also creates an internal headless service that can be used by applications deployed inside the same Kubernetes namespace to connect to the Couchbase cluster.

      Run the following command to see the newly created pods:

      • Kubernetes

      • OpenShift

      kubectl get pods
      oc get pods

      The output should look like:

      NAME                                  READY     STATUS    RESTARTS   AGE
      cb-example-0000                       1/1       Running   0          1m
      cb-example-0001                       1/1       Running   0          1m
      cb-example-0002                       1/1       Running   0          1m
      couchbase-operator-1917615544-pd4q6   1/1       Running   0          8m

      A CouchbaseCluster object is also created for the cluster and can be used to get health and status information about the cluster.