Maybe this is a stupid question but I noticed on a new server (Ubuntu 22.04 / LXD 5.0) that the UIDs/GIDs of the container’s files (under /var/snap/lxd/common/lxd/storage-pools/default/containers/WHATEVER/rootfs are no longer “shifted”, e.g., rootfs/home/ubuntu is owned by UID 1000 instead of idmap.base + 1000, which is the case on my other server (Ubuntu 20.04 / LXD 4.0). I’ve been browsing the documentation but cannot find anything useful regarding this. Is this inteded and why was this changed? Just curious. Also: can this be reverted to the previous behavior?
Yes, whenever possible we avoid that expensive step.
In the past, you could opt-in to the shiftfs kernel module on Ubuntu systems to avoid the pre-startup shifting of the container. These days, we have a proper in-kernel solution called VFS idmap which is enabled by default on support filesystems.