Support Kolla image tags overrides per environment

[grzegorzkoper]

No description provided.

[gemini-code-assist]

Code Review

This pull request introduces support for overriding Kolla image tags per environment, enhancing flexibility in deployment configurations. The changes involve updating documentation in etc/kayobe/kolla/globals.yml and tools/kolla-images.py to reflect this new capability. The Python script tools/kolla-images.py has been refactored to include new functions for reading, merging, and loading image tags from both a base file and an optional environment-specific override file. This refactoring improves modularity and robustness, with appropriate error handling for missing or invalid tag configurations. The overall change is a positive step towards more dynamic and environment-aware image tag management.

[Alex-Welsh]

I'll do a full review some other time, but I just want to mention:

1. This is a really nice feature
2. The Python component of SKC is starting to grow. I think that's a good thing. Ansible is great for some tasks but can become a complete mess when you try to do anything complicated. But we should think about python unit tests & linting
3. needs a reno

[jackhodgkiss]

Nice feature and could be useful in some instances.

Could it be made possible that this is toggleable and opt in.

I have it set within some deployments where the kolla-images-tags is pinned within deployment environments to avoid merges of SKC impacting what images are available. Though I could see these environments being impacted by this change unexpectedly.

[grzegorzkoper]

Nice feature and could be useful in some instances.

Could it be made possible that this is toggleable and opt in.

I have it set within some deployments where the kolla-images-tags is pinned within deployment environments to avoid merges of SKC impacting what images are available. Though I could see these environments being impacted by this change unexpectedly.

Previously the whole dict had to be overwritten in env files.Removing the main file and keeping only env overrides was also producing an error.It all felt inconsistent with how we handle other files in multi-env setups.
With this approach you can just remove the main file and keep your environment files intact.

I agree that this will impact merge behaviour one way or another, so made the change opt-in as requested.