Problem with aufs/overlayfs on top of nfs4

[Christoph]

Hello,

on a server, I have several chroot directories with different Ubuntu LTS versions installed. Each of these directories is exported readonly as an NFSROOT for clients being booted by
PXE; on the clients, the initrd (created by dracut) "makes the root directory writable" by
using aufs on top of the readonly nfs import. This works for clients with Ubuntu LTS versions up to 18.04, but it does not work correctly anymore on an Ubuntu 20.04 client: New files and directories can be created directly in /, but in subdirectories like /usr, /var etc., I get an error "Operation not supported" when I try to create a new file or directory.

Because of that problem, I switched from aufs to overlayfs, but overlayfs has the same error.

Regards
  Christoph

[Ubuntu Foundations Team Bug Bot (crichton)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. It seems that your bug report is not filed about a specific source package though, rather it is just filed against Ubuntu in general. It is important that bug reports be filed about source packages so that people interested in the package can find the bugs about it. You can find some hints about determining what package your bug might be about at https://wiki.ubuntu.com/Bugs/FindRightPackage. You might also ask for help in the #ubuntu-bugs irc channel on Freenode.

To change the source package that this bug is filed about visit https://bugs.launchpad.net/ubuntu/+bug/1907552/+editstatus and add the package name in the text box next to the word Package.

[This is an automated message. I apologize if it reached you inappropriately; please just reply to this message indicating so.]

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This bug is missing log files that will aid in diagnosing the problem. While running an Ubuntu kernel (not a mainline or third-party kernel) please enter the following command in a terminal window:

apport-collect 1907552

and then change the status of the bug to 'Confirmed'.

If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'.

This change has been made by an automated script, maintained by the Ubuntu Kernel Team.

[Christoph (christoph-pleger-cs)]

As it is impossible to call apport-collect on the nfs client, I cannot add log files.