Internal Image Registry

Background

I’ve been writing a lot of code lately, and to shorten the developer inner loop, I’ve been building locally too. That means I’ve been building images with Podman but I need a place to put them so I can deploy and test them. Quay.io is free and open to all, but I don’t want to clutter that space with my dev builds. What I like to do is use the OpenShift internal registry for development purposes, so I’ll demonstrate how to do that here.

Instructions

The first thing we need to do is expose the image registry by creating a Route. The Image Registry is managed by an Operator, so the only way to do that is to patch the ImageRegistry object’s configurations.

oc patch configs.imageregistry.operator.openshift.io/cluster --patch '{"spec":{"defaultRoute":true}}' --type=merge

Once that change has taken affect, a default-route will be created. You can use this snippet to log into the registry with Podman. This assumes you’re already logged in.

podman login $(oc get route default-route -o jsonpath='{.spec.host}' -n openshift-image-registry) -u $(oc whoami) -p $(oc whoami -t)

Note: If you’re planning on doing this for a non-human process, such as a pipeline - you’ll need to create a service account token

# This will give you a token that's valid for 1 year, but the default is 1 hour
oc create token builder --duration 525600m

Use this to grab the route’s hostname.

oc get route default-route -o jsonpath='{.spec.host}' -n openshift-image-registry

Assuming you’ve already built the image, use that hostname in the script above to retag your image.

podman tag <existing tag> <new tag>

Note that will looklike the following:

<route_output>/<namespace>/<image-name>:<version>

Now all you gotta do is podman push it!