/tmp read-only with stretch and FAI 5.1.2

[Thomas Lange]

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