$ mkdir memcached-operator
To demonstrate the basics of setting up and running a Go-based Operator using tools and libraries provided by the Operator SDK, Operator developers can build an example Go-based Operator for Memcached, a distributed key-value store, and deploy it to a cluster.
The Red Hat-supported version of the Operator SDK CLI tool, including the related scaffolding and testing tools for Operator projects, is deprecated and is planned to be removed in a future release of OKD. Red Hat will provide bug fixes and support for this feature during the current release lifecycle, but this feature will no longer receive enhancements and will be removed from future OKD releases. The Red Hat-supported version of the Operator SDK is not recommended for creating new Operator projects. Operator authors with existing Operator projects can use the version of the Operator SDK CLI tool released with OKD 4.17 to maintain their projects and create Operator releases targeting newer versions of OKD. The following related base images for Operator projects are not deprecated. The runtime functionality and configuration APIs for these base images are still supported for bug fixes and for addressing CVEs.
For the most recent list of major functionality that has been deprecated or removed within OKD, refer to the Deprecated and removed features section of the OKD release notes. For information about the unsupported, community-maintained, version of the Operator SDK, see Operator SDK (Operator Framework). |
Operator SDK CLI installed
OpenShift CLI (oc
) 4.17+ installed
Go 1.21+
Logged into an OKD 4.17 cluster with oc
with an account that has cluster-admin
permissions
To allow the cluster to pull the image, the repository where you push your image must be set as public, or you must configure an image pull secret
You can build and deploy a simple Go-based Operator for Memcached by using the Operator SDK.
Create a project.
Create your project directory:
$ mkdir memcached-operator
Change into the project directory:
$ cd memcached-operator
Run the operator-sdk init
command
to initialize the project:
$ operator-sdk init \
--domain=example.com \
--repo=github.com/example-inc/memcached-operator
The command uses the Go plugin by default.
Create an API.
Create a simple Memcached API:
$ operator-sdk create api \
--resource=true \
--controller=true \
--group cache \
--version v1 \
--kind Memcached
Build and push the Operator image.
Use the default Makefile
targets to build and push your Operator. Set IMG
with a pull spec for your image that uses a registry you can push to:
$ make docker-build docker-push IMG=<registry>/<user>/<image_name>:<tag>
Run the Operator.
Install the CRD:
$ make install
Deploy the project to the cluster. Set IMG
to the image that you pushed:
$ make deploy IMG=<registry>/<user>/<image_name>:<tag>
Create a sample custom resource (CR).
Create a sample CR:
$ oc apply -f config/samples/cache_v1_memcached.yaml \
-n memcached-operator-system
Watch for the CR to reconcile the Operator:
$ oc logs deployment.apps/memcached-operator-controller-manager \
-c manager \
-n memcached-operator-system
Delete a CR.
Delete a CR by running the following command:
$ oc delete -f config/samples/cache_v1_memcached.yaml -n memcached-operator-system
Clean up.
Run the following command to clean up the resources that have been created as part of this procedure:
$ make undeploy
See Operator SDK tutorial for Go-based Operators for a more in-depth walkthrough on building a Go-based Operator.