Have a plan for the transition from UBI9/8 images to C9S for ODH and RHEL for RHODS

[atheo89]

Due to a lot of missing packages on UBI-based images, it requires moving to CentOS Stream 9 base images on the upstream repo, and RHEL for the downstream.

Things to consider (so far):

• This differentiation in the base image between the two repositories may lead to use two different repositories. Let's think about how we may avoid double maintenance. (Maybe by using submodules)
• On downstream, we need to be registered on the subscription manager

[maroroman]

We had a conversation about this issue and identified a possible solution that would let us avoid having to maintain 2 repositories separately:

In the notebooks repo, for development purposes, there could be added an environment variable containing the base image chosen by the developer.
i.e. Instead of this:

# Build and push base-ubi8-python-3.8 image to the registry
.PHONY: base-ubi8-python-3.8
base-ubi8-python-3.8:
     $(call image,$@,base/ubi8-python-3.8)

We could use this:

# Build and push base image to the registry
.PHONY: base
base:
     $(call image,$@, ${BASE_IMAGE})

Where BASE_IMAGE=base/c9s-python-3.9 (or its equivalents chosen by the dev, like base/ubi9-python-3.9 for developing downstream)

And the rest of the images would use this base that has been set by the env var.

For CI purposes, a second PR would be created in https://github.com/openshift/release/blob/master/ci-operator/config/opendatahub-io/notebooks/opendatahub-io-notebooks-main.yaml

There, all UBI images would be deleted, and replaced by their C9S equivalents, i.e.:

  - context_dir: base/ubi9-python-3.9
    dockerfile_path: Dockerfile
    to: base-ubi9-python-3.9
  - context_dir: jupyter/minimal/ubi9-python-3.9
    dockerfile_path: Dockerfile
    from: base-ubi9-python-3.9
    to: jupyter-minimal-ubi9-python-3.9

Would be replaced with:

  - context_dir: base/c9s-python-3.9
    dockerfile_path: Dockerfile
    to: base-c9s-python-3.9
  - context_dir: jupyter/minimal/c9s-python-3.9
    dockerfile_path: Dockerfile
    from: base-c9s-python-3.9
    to: jupyter-minimal-c9s-python-3.9

The downstream CI would not require changes in this case.

cc @atheo89 @harshad16
Let me know what you think about this solution.

[harshad16]

Thanks for the possible solution for making the change.
Seems like a doable solution.

We should also evaluate the implication of making a change from centos and rhel
would like to cause any kinda concern downstream as well.

[harshad16]

Necessary image are split between UBI/Centos/RHEL.
Closing this issue as the requirements are fulfilled.