Currently, the per-pool custom Dockerfiles do not trigger a build, requiring an empty MachineConfig update to be performed. Ideally, we should perform a build in response to that ConfigMap being changed.

A subproblem we'll need to solve as part of this is tagging. Currently, we tag the built image with the name of the rendered MachineConfig that we baked into the image. In this case, however, we probably don't want to do that. Instead, we might want to append the date and time of the build onto that instead. Although rpm-ostree uses only the SHA256 version of the image pullspec, we do not want those tags to clobber one another on their container image registry. I'm open to ideas around a better tagging convention.

Done When:

• Updating the on-cluster-custom-dockerfile ConfigMap will trigger a build to be performed.
• The built image is tagged with a unique tag that does not overwrite any other tag before being pushed to the specified container image registry.