Handling change in default user ID between the old and new image more gracefully

[brownleej]

trafficstars

The new unified image has a different default user ID than the old split image. This may cause problems in the transition, if the new user cannot access files written by the old user in the data directory. We should look for a way to handle this change gracefully, like inferring that the security context will change and doing a replacement as a result of that.

[johscheuer]

This is probably something we should be documenting as part of the "action required" items.

[johscheuer]

The fdb-kubernetes-monitor image will be based on the same image as the foundationdb image, so the default user ID should be the same: https://github.com/apple/foundationdb/blob/main/packaging/docker/Dockerfile#L119-L128. I'm going to close this issue. Feel free to reopen it if I missed something.