Bump - anyone :)
Please note - I'm not requesting anyone fix a deeply obscure problem.
I'm a sysadmin - I'd just be really grateful for some pointers to help
me continue debugging this myself...
Ta,
Tim
On 10/12/10 15:43, Tim Watts wrote:
Hi,
I have an NFSv4 client set up on Ubuntu 10.04.1 LTS x86. The NFSv4
server is running Centos 5.5 and we use MIT kerberos and LDAP for
users/groups. This seems to work well with Centos 5.5 clients
All works fine with my Ubuntu client, except after a while my client
acts like it loses its authentication - symptom: home directory mount
drops to "nobody" - I see the mount as "other" - no write access, can
read files that have world read bit set etc.
This can happen anytime between 48 hours and 2 hours after a full client
reboot. It seems to be triggered by active use of thunderbird via the
NFSv4 mounted home dir which suggests it may be load sensitive.
When it happens, if I unmount my home dir (killing the desktop of
course) , then remount the fault is cleared and I can work again.
What doesn't work is just doing a kinit -f or restarting idmapd or gssd.
I have run rpc.gssd in foreground debug mode and that doesn't say much
during the problem times, ditto idmapd. We are using openldap for passwd
and group lookups cached locally with nscd.
I have tried upping kernel debugging:
rpcdebug -m nfs -s vfs dircache lookupcache pagecache proc xdr file root
callback client mount all
but I'm not sure what I'm looking for.
The symptoms feel like the kernel is losing the ticket or timing it out
or possibly the ID mapping is failing - is there any way to examining
the state of the kernel ticket cache or anything else I could be looking
for?
I am tempted to say this is a bug, possibly in the Ubuntu build, but I
would like to investigate further.
Any pointers much appreciated as to how I might isolate the fault further.
Cheers
Tim
--
Tim Watts
Linux Sysadmin, High Energy Physics, Imperial College London
Tel: 020 759 47809
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