NFS over Unionfs prevents updating existing files

The unionfs in hardy is an older 1.4 version, just used for basic unionfs and live-cd. If you want better unionfs, use aufs instead, which has support for NFS overlays.

13:58:20 < BenC> siretart: "crashed" is a loose word in this context, since unionfs didn't crash either
13:58:34 < BenC> siretart: what exactly happened when you tried to use unionfs (in what way did it fail)
13:58:45 < BenC> aufs I mean
13:59:21 < siretart> I have to admit that I can only tell from memory. I gave it a quick shot, and on the first glance, it looked
                     like aufs wouldn't work with NFS at all
13:59:29 < BenC> If we can give you an updated aufs to resolve this, we can do that...but updating unionfs to work with NFS is not
                 going to happen
13:59:42 < siretart> hm. I see
14:00:18 < BenC> siretart: how hard is it for you to download and build latest aufs with our kernel headers and test it for fai?
...
14:03:54 < siretart> ok. will try that. thanks!

A workaround would be to remove (at least) /etc/resolv.conf, /etc/syslog.conf and /etc/mtab from the nfsroot. Other files might have to be removed too depending on your setup.

This bug was fixed in the package fai - 3.2.4+svn4837-0ubuntu2

---------------
fai (3.2.4+svn4837-0ubuntu2) hardy; urgency=low

  * upload to hardy

fai (3.2.4+svn4837-0ubuntu2~ppa3) hardy; urgency=low

  * simple config GRUB/10-setup: add to kernel-img.conf postinst and postrm
    hook settings that run update-grub. Without them, grub's menu.lst is not
    updated on linux image installation/removal.

fai (3.2.4+svn4837-0ubuntu2~ppa2) hardy; urgency=low

  * don't install menu.lst and GRUB postinst script at all in the binary
    package by removing them in the clean rule of debian/rules
  * remove console-data support, show how to preseed console-setup in the
    example class GERMAN. (LP: #207756)

fai (3.2.4+svn4837-0ubuntu2~ppa1) hardy; urgency=low

  [ Christian Meier ]
  * bin/fai, lib/get-config-dir-nfs: always use -n option in romountopt to
    prevent accessing /etc/mtab in read-only environment
    (closes: LP: #207582)
  * fix grub example (closes LP: #187659)
    * remove menu.lst of examples
    * move the postinst script of menu.lst to
      examples/simple/scripts/GRUB/10-setup and modify it to let update-grub
      do the configuration of menu.lst
  * workaround for not correctly working unionfs over nfs
    * create nfshooks (/etc/fai/10-unionfs-workaround) that delete certain
      files in nfsroot that will be created automatically through fai scripts.
      (LP: #197006)
  * add ghostscript to build dependencies
  * don't fail build if there are no postinst scripts in the 'simple-example'
    configuration space

  [ Reinhard Tartler ]
  * add genisofs alternative to mkisofs in fai-server and fai-quickstart
    packages (LP: #156836)

 -- Reinhard Tartler <email address hidden> Tue, 01 Apr 2008 12:41:34 +0200