I tried this on a Supermicro board and a Sun box. On both systems the
system would reboot randomly so I tuned it off. This is a serious
problem of false positives. In a cluster, you may need to notify the
scheduler in someway when a node reboots. Can someone elaborate on
this? Specifically for torque, PBS and Sun GE.
Regarding this:
Have you guys used watchdog timers? Maybe there is a way to build a
circuit-breaker around the principle so that if a node reboots
automatically more than 3 times then watchdog gives up?
It would far simpler to request the vendor to program thier firmware to
log each reboot and set a limitation there as well as event
notifications via email, snmp or other means. The more configurable the
better.
Kevin
Rahul Nabar wrote:
I wanted to get some opinions about if watchdog timers are a good idea
or not. I came across watchdogs again when reading through my IPMI
manual. In principle it sounds neat: If the system hangs then get it
to reboot after, say, 5 minutes automatically. But, in practice, maybe
it is a terrible idea.
Of course, one might say, a well configured HPC compute-node
shouldn't be getting to a hung point anyways; but in-practice I see a
few nodes every month that can be resurrected by a simple reboot.
Admittedly these nodes are quite senile.
The danger, seems to me: What if a node kept crashing (due to say, a
bad HDD or something). Then a watchdog would merely keep rebooting
this node a hundred times. Not such a good thing.
Have you guys used watchdog timers? Maybe there is a way to build a
circuit-breaker around the principle so that if a node reboots
automatically more than 3 times then watchdog gives up?
If one had to do the watchdogging should one do the resets locally
using the IPMI local interface (hogs cpu cycles) or a central
Nagios-like system that could issue such a command. Many scenarios
seem possible. The prospect of a automated system doing a reboot at
3am seems more tempting than me having to do this manually.
--
Kevin C. Abbey
System Administrator
Rutgers University - BioMaPS Institute
Email: kab...@biomaps.rutgers.edu
Hill Center - Room 259
110 Frelinghuysen Road
Piscataway, NJ 08854
Phone and Voice mail: 732-445-3288
Wright-Rieman Laboratories Room 201
610 Taylor Rd.
Piscataway, NJ 08854-8087
Phone: 732-445-2069
Fax: 732-445-5958
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