Quickstart for Go-based Operators

This guide walks through an example of building a simple memcached-operator using tools and libraries provided by the Operator SDK.

Prerequisites

• Go through the installation guide.
• Make sure your user is authorized with cluster-admin permissions.
• An accessible image registry for various operator images (ex. hub.docker.com, quay.io) and be logged in to your command line environment.
  • example.com is used as the registry Docker Hub namespace in these examples. Replace it with another value if using a different registry or namespace.
  • Authentication and certificates if the registry is private or uses a custom CA.

Steps

1. Create a project directory for your project and initialize the project:

mkdir memcached-operator
cd memcached-operator
operator-sdk init --domain example.com --repo github.com/example/memcached-operator

Note If your local environment is Apple Silicon (darwin/arm64) use the go/v4 plugin which provides support for this platform by adding to the init subCommand the flag --plugins=go/v4

1. Create a simple Memcached API:

operator-sdk create api --group cache --version v1alpha1 --kind Memcached --resource --controller

1. Build and push your operator’s image:

make docker-build docker-push IMG="example.com/memcached-operator:v0.0.1"

OLM deployment

1. Install OLM:

operator-sdk olm install

1. Bundle your operator, then build and push the bundle image (defaults to example.com/memcached-operator-bundle:v0.0.1):

make bundle IMG="example.com/memcached-operator:v0.0.1"
make bundle-build bundle-push BUNDLE_IMG="example.com/memcached-operator-bundle:v0.0.1"

1. Run your bundle. If your bundle image is hosted in a registry that is private and/or has a custom CA, these configuration steps must be complete.

operator-sdk run bundle <some-registry>/memcached-operator-bundle:v0.0.1

1. Create a sample Memcached custom resource:

$ kubectl apply -f config/samples/cache_v1alpha1_memcached.yaml
memcached.cache.example.com/memcached-sample created

1. Uninstall the operator:

operator-sdk cleanup memcached-operator

Direct deployment

1. Deploy your operator:

make deploy IMG="example.com/memcached-operator:v0.0.1"

1. Create a sample Memcached custom resource:

$ kubectl apply -f config/samples/cache_v1alpha1_memcached.yaml
memcached.cache.example.com/memcached-sample created

1. Uninstall the operator:

make undeploy

Run locally (outside the cluster)

This is recommended ONLY for development purposes

1. Run the operator:

make install run

1. In a new terminal tab/window, create a sample Memcached custom resource:

$ kubectl apply -f config/samples/cache_v1alpha1_memcached.yaml
memcached.cache.example.com/memcached-sample created

1. Stop the operator by pressing ctrl+c in the terminal tab or window the operator is running in

Next Steps

Read the full tutorial for an in-depth walkthrough of building a Go operator.