Monday, August 17, 2009

Munin, again

More problems come when I'm just starting to use Munin-Node to monitor several Windows 2003 servers :
  1. the memory value reported by Munin-Node are all wrong. The sum of app and unused is not related to total physical memory installed in the servers. It turns out that the Windows API used returns 64-bit values, and simple change to the format specified fixes the problem.
  2. external plugin doesn't work. Turns out that the external plugin must not print the trailing newline when invoked by 'name' argument, and it also must prints a line of '.' after each 'config' and 'value' (or default) invocation.
  3. after several days of running, external plugins stopped working. I used sysinternals' process explorer in the server, and found out that there is some chance that external plugin invocation doesn't close the listener thread. After a few days the unclosed threads became too much and prevent the Munin-Node service from spawning new external plugins.

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