FAI with nfsroot on stretch failing with read-only error at /tmp/fai

[Bill MacAllister]

On Wednesday, June 28, 2017 3:21:58 PM PDT, Nat Sincheler wrote:
> We are able to PXE boot and do an NFS mount, but we are getting 
> a "Read-only file system" error when FAI is trying to make the 
> directory /tmp/fai.
>
> We get to the point where we see this at the console:
>
> INIT: version 2.88 booting
> cat: /sys/class/net/eth0/name_assign_type: Invalid argument
> cat: /sys/class/net/eth0/name_assign_type: Invalid argument
> [    35.498423] dracut: Switching root
> mkdir: cannot create directory '/tmp/fai': Read-only file system
> chown: cannot access 'tmp/fai': No such file or directory
>
>
> A screen-shot of the console shows the error:
> https://drive.google.com/file/d/0B6Uk8YXuZvLJb1Q0eGNPVDBva3c/view?usp=sharing
>
>
> Any ideas?

Sounds like you have this problem describe by Thomas in a previous
response.

Bill


When using a 4.X kernel FAI uses overlayfs on top of the read-only
nfsroot for making it writeable. This works only when using NFS v3.
I'm pretty sure this must be fiexed in overlayfs.

If the install client mounts the nfsroot via NFSv4 (using NFS 4.2 with
the recent 4.9 kernel) the nfsroot will remain read-only and FAI
cannot proceed.

You can force NFS v3 on the server side by adding a line to
/etc/exports as described in
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=676883#10

Or you can add a nfs option into the pxelinux.cfg file when specifying
the mount address for the nfsroot:
root=1.2.3.4:/srv/fai/nfsroot:vers=3

If you want to experiment with different NFS v4 versions (using
minorversion) you can use something like this
root=1.2.3.4:/srv/fai/nfsroot:vers=4,minorversion=0

BTW, there's a new package aufs-dkms which includes aufs for 4.X
kernel. It did not test it yet. Maybe this is a solution for using
nfsroot via NFS v4 using a 4.X kernel.
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-- 
Bill