Push Custom Images to Openshift Local

This post describes the next step in our journey to deploy MTV (Migration Toolkit for Virtualization) on Openshift Local: deploying a custom image to Openshift Local without going through an external registry like quay.io


Set up an Openshift Local cluster and deploy MTV on it as described here (note that you should also make the PVs accessible to the pods for being able to start VMs).

Clone the repository of Forklift and make sure you are able to build the image of forklift-controller with make build-controller.

Expose the image-registry

Do the following steps that are taken from the Openshift documentation:

$ HOST=$(oc get route default-route -n openshift-image-registry --template='{{ .spec.host }}')
$ oc get secret -n openshift-ingress  router-certs-default -o go-template='{{index .data "tls.crt"}}' | base64 -d | sudo tee /etc/pki/ca-trust/source/anchors/${HOST}.crt  > /dev/null
$ sudo update-ca-trust enable
$ podman login -u kubeadmin -p $(oc whoami -t) $HOST

Note that the last step above is different than what is written in the above mentioned Openshift documentation, this command shouldn’t be executed with sudo.

Push an image to the exposed registry

Tag an image with $HOST as the registry and push it, for example:

$ podman tag <image-id> $HOST/openshift/forklift-controller:devel
$ podman push $HOST/openshift/forklift-controller:devel

Specifically, for forklift-controller this can be achieved with:

$ export IMG=$HOST/openshift/forklift-controller:devel
$ make push-controller

Redirect the pod to use the image from the cluster’s image registry

This part depends on the way the application is deployed, here I’ll describe a common practice for applications that are deployed using operators in which the image from the internal/cluster’s image registry is injected by the operator.

First, identify the ClusterServiceVersion instance in the relevant namespace (in my case it was called mtv-operator.v2.3.1 in the openshift-mtv namespace).

Then, edit it and specify the image that was pushed to the internal registry, in my case it was done by editing mtv-operator.v2.3.1:

$ oc edit csv -n openshift-mtv mtv-operator.v2.3.1

And setting the value of RELATED_IMAGE_CONTROLLER to: image-registry.openshift-image-registry.svc:5000/openshift/forklift-controller:devel

Finally, delete the pod, in my case forklift-controller, so another one would start with the new image from the internal registry.

Written on December 2, 2022