Hi Jeff, hi Stephen, I found the problem. It's NFS v4 again. If I export my nfsroot via NFS v4 I also have the 'operation not supported' error message when doing a touch /tmp/test.
On your FAI install server you can add this line to the /etc/exports /srv/nfs4 1.2.3.4/25(fsid=0,ro,no_subtree_check) And create an empty /srv/nfs4 directory. Replace 1.2.3.4/25 with your network settings. fsid=0 will force to export this empty directory using NFS v4, and all other entries in /etc/exports with NFS v3. So, there seems to be a bug in overlayfs when using NFS v4. -- regards Thomas