We saw the same problem occur when we blocked the root a/c and moved to a sudo 
environment. The sync_files would not work. Shiang-Tais solution is what we 
followed as well.

-Ibad Kureshi
HPC Admin, University of Huddersfield
________________________________________
From: Shiang-Tai Lin [st...@ntu.edu.tw]
Sent: Monday, May 28, 2012 11:57 PM
To: oscar-users@lists.sourceforge.net
Subject: Re: [Oscar-users] corrupt passwd files on nodes

Hi Lutz,

Our cluster had the same problem one or twice in the past.

The password on nodes can be synchronized with that of the server with the 
following command
/opt/sync_files/bin/sync_files
This command is executed every 15 min via cron (cat /etc/crontab)
*/15 * * * * root env USER=root /opt/sync_files/bin/sync_files >/dev/null 2>&1

If something goes wrong during the sync process, the passwd file will be 
corrupted. In this case, we had to login the node with single user mode (so 
that the root password is not needed), and then copy the password files from 
the server.

Regards,
ST

On 2012/5/28 下午 09:01, dr...@directbox.com<mailto:dr...@directbox.com> wrote:
Hi all,

I have now repeatedly encountered a problem and would like to know if it is a 
known / widespread one:

time and again some (or all) of the nodes of one of our clusters become 
completely inaccessible (i.e. one cannot ssh or console-login to nodes). By 
rebooting a node from a live medium one finds that /etc/passwd has size 0; 
since I also find that /etc/groups and /etc/shadow have the same date, I assume 
that OSCAR has got some mechanism to distribute these files according to some 
schedule and that corruption can occur during the process of pushing those 
files down from the head node - am I right?

Now my question is, how could one analyze, why the cluster does this and how 
could one fix it?

Regards
Dr Lutz Ackermann
MMC - UL


PS: It's an OSCAR 5 cluster installed on a RedHat derivative:
$ cat /proc/version
Linux version 2.6.9-78.ELsmp 
(brewbuil...@ls20-bc2-14.build.redhat.com<mailto:brewbuil...@ls20-bc2-14.build.redhat.com>)
 (gcc version 3.4.6 20060404 (Red Hat 3.4.6-10)) #1 SMP Wed Jul 9 15:46:26 EDT 
2008
$ cat /etc/*release
Red Hat Enterprise Linux AS release 4 (Nahant Update 7)




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--
Shiang-Tai Lin, Professor
Department of Chemical Engineering
National Taiwan University
TEL: +886-2-33661369
FAX: +886-2-23623040
Email: st...@ntu.edu.tw<mailto:st...@ntu.edu.tw>
Webpate: http://web.che.ntu.edu.tw/stlin/



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