In the rootless podman doc, it is stated that:
- Can not use overlayfs driver, but does support fuse-overlayfs
- Ubuntu supports non root overlay, but no other Linux distros do.
So overlayfs is not mountable in userspace in general, but ubuntu authorizes it, so it's not a technical difficulty (a setuid program could obviously do it).
- Why is
overlayfsin general not mountable from userspace?
- Why is not podman overriding this behavior to get an ubuntu-like behavior using a setuid program?