1. Documentation
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Creating applications from installed Operators

You can deploy applications on your OKD cluster from Operators that a cluster administrator installed. Use the Installed Operators page in the web console to create an application from an Operator custom resource (CR) API.

Additional resources

Creating an etcd cluster using an Operator

You can create an etcd cluster using the etcd Operator in the OKD web console. The Operator creates the pods, services, and other cluster resources for you.

Prerequisites

  • Access to an OKD 4.21 cluster.

  • The etcd Operator already installed cluster-wide by an administrator.

Procedure

  1. Create a new project in the OKD web console for this procedure. This example uses a project called my-etcd.

  2. Navigate to the Ecosystem → Installed Operators page.

    The Operators installed on the cluster by the cluster administrator and available for use are shown here as a list of cluster service versions (CSVs). Each CSV launches and manages the software provided by the Operator.

    You can get this list from the CLI by running the following command:

    $ oc get csv

  3. On the Installed Operators page, click the etcd Operator to view more details and available actions.

    As shown under Provided APIs, this Operator makes available three new resource types, including one for an etcd Cluster, the EtcdCluster resource.

    These objects work similarly to the built-in native Kubernetes ones, such as Deployment or ReplicaSet, but contain logic specific to managing etcd.

  4. Create a new etcd cluster:

    1. In the etcd Cluster API box, click Create instance.

    2. Optional: Modify the minimal starting template of an EtcdCluster object, such as the size of the cluster.

    3. Click Create to finalize. This triggers the Operator to start up the pods, services, and other components of the new etcd cluster.

  5. Click the example etcd cluster.

  6. Click the Resources tab.

    Your project contains several resources that the Operator created and configured.

  7. Verify that a Kubernetes service exists that allows you to access the database from other pods in your project.

  8. Optional: To grant another user permission to create Operator-managed applications in the project, add the edit role by running the following command:

    $ oc policy add-role-to-user edit <user> -n <target_project>

    Users with the edit role in a project can create, manage, and delete Operator-managed application instances, such as an etcd cluster.

Results

You have an etcd cluster that reacts to failures and rebalances data as pods become unhealthy or migrate between nodes in the cluster. Cluster administrators or developers with proper access can use the database with their applications.