Switch to centos:stream9-minimal

[austlane]

This PR switches the base image to centos:stream9-minimal which uses microdnf and does not bundle Python3.9, allowing us to ship a final image without Python 3.9 installed at all.

Also removes subversion, as it hard-depends upon python3.9, no love lost.

This is another take on #207 and #244
EDIT: Rebased after #207 was merged.

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Currently this PR relies upon ansible/ansible-builder#664 which enables dependency exclusions, allowing overrides of bindep.txt dependencies directly inherited from collections.

This PR will be marked as a Draft until ansible/ansible-builder#664 is merged.

EDIT: ansible/ansible-builder#664 has been merged. This PR is ready for review.

[austlane]

This package always links to python3.9 on el9. Replaced with alternatives commands below.

[austlane]

Requires ansible/ansible-builder#664

EDIT: ansible/ansible-builder#664 has been merged! 🎉

[TheRealHaoLiu]

@austlane this is awesome, is this PR ready?

[austlane]

@austlane this is awesome, is this PR ready?

This PR works as-is 👍 But I'd imagine it shouldn't be merged until ansible/ansible-builder#664 is merged into ansible-builder, depending directly on a PR seems hacky.
I'll rebase when it's merged and remove my changes to requirements.txt.

[TheRealHaoLiu]

any particular reason for switching from stream9 to stream9-minimal?

[austlane]

The stream9-minimal images do not include python at all out of the box, which allows us to avoid unnecessarily bundling two versions of python in awx-ee (3.9 + 3.11). That was the primary motivation.

[austlane]

I'll be rebasing this PR now that #207 has been merged 👍

I still think this approach is worth consideration to keep the EE light / avoid shipping two Pythons.

EDIT: Rebased :)