Another day, another globus error

After almost 5 years at this lark, I thought I'd got a handle on most of the cryptic globus errors. However, today atlas production jobs started failing with errors like this:

018 (9163559.001.000) 03/05 11:25:27 Globus job submission failed!

  Reason: 22 the job manager failed to create an internal script argument file

Google didn't provide any help, but after asking on LCG rollout, it looked like the problem was the number of files in the relevant user's account. This turned out to be because the script /opt/lcg/sbin/cleanup-grid-accounts.sh that cleans up the grid accounts hadn't run in some days and there were almost 32000 files under that directory.

So there's yet another vital cog in the grid wheel that can fail fairly silently and cause inexplicable errors! Time to add a nagios sensor to check that this cron job runs successfully every night ...

Home-made Torque monitoring

I've always been frustrated by the tools for finding out what's going on with Torque/Maui. In particular, it's hard to get an overview of the cluster state. So I compiled up pbs_python and wrote a little web CGI application to provide the information I was interested in. It shows information on jobs running on each cluster node: owner, efficiency, memory usage. It colour-codes the details: grey for under-utilisation and red for over-utilisation. Not perfect but useful for me.

It's available at http://grid.ie/distribution/clustermon

P.S. if something better exists out there, I'd be very interested in hearing about it. I've never found anything that does quite what I want.

Cron Security

After the recent Security Challenge we became aware that any pool user could create at and cron jobs on our cluster: obviously not good for security or scheduling.

Initially we wondered if we'd need to create SELinux policies to restrict this but it's much simpler than that. Cron and at support simple allow and deny files to control which users can use the commands. /etc/cron.deny specifies which users are denied access, and /etc/cron.allow specifies which users are allowed. (For full details man crontab.)

In /etc/cron.deny we put:

   ALL

and in /etc/cron.allow we put:

   root
   admina
   adminb
   ...

where admina, adminb and so on are the admin users who should have cron access. /etc/at.deny and /etc/at.allow are configured the same way.

This is configured through Quattor. For now we're using the filecopy component to install the config files, but this might be a useful extension to the cron component.

LHC switch-on in Ireland

We had a great day yesterday at Trinity's Science Gallery where we had a live feed from CERN running all day. There was a lot of press interest and the grid featured heavily due to the fact that the grid group here at TCD makes up half of Ireland's LHC involvement (the other half being the particle physics group at UCD who are in LHCb). We had the GridPP real-time monitor running all day, which provoked a lot of interest and made it onto national TV. One interesting side-effect of all the publicity is that the man on the street now knows that Ireland is one of the few European countries that isn't a member of CERN -- maybe it will cause the politicians to reconsider.

geclipse: a nice grid UI at last?

I've just been playing around with geclipse and I like what I see. It wraps up the fiddly business of VOMs proxies, information system queries, etc. so you don't have to worry about them. Once I'd downloaded the latest milestone release via eclipse's update manager and set up a VO I was able to submit a job. The WMS was discovered from the information system. They use JSDL to describe jobs, but you fill in the description using dialog boxes -- it can also translate to JDL. There are lots of cool things that I haven't even looked at yet like an interface to amazon ec2 and to local batch systems (to view queues etc.), also visualisation plugins allowing things like interactive jobs.

This looks like a great interface for grid beginners, especially those who're already familiar with eclipse. I knew that sooner or later someone would get round to writing some good software for submitting grid jobs!

Who is that masked user?

Trying to get a better handle on usage of our cluster, I for the first time realised that Maui actually provides quite a nice way of displaying the efficiency of jobs. It doesn't sort them the way you'd like, but then that's what "sort" is for. Here's the "bottom 10" jobs on our system:

[root@gridgate gridmapdir]# showq -r|sort -n  -k 4|sed -e 's/^[ \t]*//' -e '/^$/d'|head -n 10
JobName  S Par  Effic  XFactor  Q      User    Group    MHost Procs   Remaining            StartTime
447 Jobs     447 of   683 Processors Active (65.45%)
550825_ R DEF   7.53      0.1 DE    fus098   fusion    wn019     1     7:45:00  Fri Mar 28 11:16:42
550438_ R DEF   9.31      0.1 DE    fus098   fusion    wn056     1     1:33:37  Fri Mar 28 05:05:04
550818_ R DEF   9.51      0.0 DE    fus098   fusion    wn072     1     5:19:15  Fri Mar 28 08:50:40
550439_ R DEF   9.65      0.1 DE    fus098   fusion    wn056     1     1:33:37  Fri Mar 28 05:05:04
550429_ R DEF  10.08      0.0 DE    fus098   fusion    wn062     1    00:39:47  Fri Mar 28 04:11:18
550437_ R DEF  10.19      0.1 DE    fus098   fusion    wn056     1     1:33:26  Fri Mar 28 05:05:04
550417  R DEF  10.28      0.1 DE    fus098   fusion    wn011     1    00:27:03  Fri Mar 28 03:58:28
550441_ R DEF  10.30      0.1 DE    fus098   fusion    wn056     1     1:33:40  Fri Mar 28 05:05:04

Looks like I need to find out who this fus098 guy is. Normally my method for doing this is to grep through /var/log/globus-gatekeeper.log but I finally got sick of this and wrote a little python script to translate the funny system used in /etc/grid-security/gridmapdir (documented here) and output the complete set of pool account mappings. I was going to implement all sorts of fancy options for outputting a particular user's mapping etc. but decided I could do what I needed with grep so I'll leave the fancification to someone else. The script is available here and here's some sample usage:

What are the mappings for users with "childs" in their DN?

[childss@gridgate childss]$ ./poolmapping |grep -i childs
dte053:/c=ie/o=grid-ireland/ou=cs.tcd.ie/l=ra-tcd/cn=stephen o. childs:dteam
solovo003:/c=ie/o=grid-ireland/ou=cs.tcd.ie/l=ra-tcd/cn=stephen o. childs:solovo
webcom050:/c=ie/o=grid-ireland/ou=cs.tcd.ie/l=ra-tcd/cn=stephen o. childs:webcom
cosmo007:/c=ie/o=grid-ireland/ou=cs.tcd.ie/l=ra-tcd/cn=stephen o. childs
cosmo004:/c=ie/o=grid-ireland/ou=cs.tcd.ie/l=ra-tcd/cn=stephen o. childs:cosmo
gitest042:/c=ie/o=grid-ireland/ou=cs.tcd.ie/l=ra-tcd/cn=stephen o. childs:gitest

What DN is mapped to dte053?

[childss@gridgate childss]$ ./poolmapping |grep -i dte053
dte053:/c=ie/o=grid-ireland/ou=cs.tcd.ie/l=ra-tcd/cn=stephen o. childs:dteam

But my proxy hasn't expired!

We have been plagued with a frustrating problem (especially in our test environment). Users would generate a new proxy, submit a job immediately and then get an error like this:

[childss@ui childss]$ edg-job-status https://cagraidsvr18.cs.tcd.ie:9000/nbPfABOjQHsG7IcFCJcYLg


*************************************************************
BOOKKEEPING INFORMATION:

Status info for the Job : https://cagraidsvr18.cs.tcd.ie:9000/nbPfABOjQHsG7IcFCJcYLg
Current Status:     Aborted 
Status Reason:      Job proxy is expired.
Destination:        gridgate02.testgrid.:2119/jobmanager-lcgpbs-test
reached on:         Tue Mar 11 08:47:31 2008
*************************************************************

Which is very annoying as the proxy obviously hasn't expired. It turns out that this is due to old jobs stuck on the RB (whose proxies have expired). The problem can be cleared by logging onto the RB, identifying old jobs for the user's DN and removing them using condor_rm. I'll leave it to someone else to explain why this arises. I hope it's been fixed in the new WMS.