Migration process from system images

[mungo312]

According to the Documentation in the Readme, there is currently no supported path from the old(system) images to the new images.

We have several production clusters which need to be migrated, because recreate is not an option.
I understood that we need to migrate to the plugin based backup approach before switching the images. Are there any other reasons for the missing support ?

[dosubot]

Hi @mungo312! I'm Dosu and I’m helping the postgres-containers team.

Yes, there are reasons beyond just the backup plugin migration for the lack of a supported path from old (system) images to the new images. The new images use a different architecture: they drop the built-in Barman Cloud executables and require backup plugins for modularity and maintainability. But more importantly, there are broader architectural changes—such as differences in entrypoints, environment variable handling, and filesystem layout—that make direct migration unsupported and potentially unsafe. These changes mean that scripts, automations, or operational expectations tied to the old images may not work with the new ones, which is why switching images on an existing cluster is not supported README.md issue #169.

At this time, I couldn't find any documented workarounds or plans for a supported in-place migration path. The recommended approach is to use the new images and backup plugins for new clusters, while legacy system images remain available for existing clusters until their eventual deprecation.

To reply, just mention @dosu.

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[sxd]

Hi @mungo312

Sadly there's no straight migration path, but if you're already using the bookworm images in your system, switching to the plugin first, and then start using the new images should be really straight forward for you since there's no changes in the underlying libc, but as Dosu mentioned, this is not documented since there's a lot of things to cover in the time that are basically how PostgreSQL behaves with the change of the libc version.

The problem is the base images, the new ones use bookworm the old ones, you can use bullseye or bookworm, but creating a migration path for those images is kind of difficult, now it could work if you trigger a major upgrade with the new images, since that will trigger the required commands to adapt to the new version, that's something that can be tested and will be awesome if you can tested and help us to document that as a step by step, can you give us a hand with that?

Regards,