For some time (probably after an upgrade, I actually don’t remember anymore) we had problems with the NFS check in Nagios on our Ubuntu 12.04 servers. The check would return
UNKNOWN: RPC program nfs udp is not running. When running the actual check from the command line:
/usr/lib/nagios/plugins/check_rpc -H '$HOSTADDRESS$' -C nfs -c2,3
the output would be:
Can't fork for rpcinfo.
It turns out that the file
/usr/lib/nagios/plugins/utils.pm has the wrong path to the
rpcinfo binary. Instead of
/usr/sbin/rpcinfo it lists
/usr/bin/rpcinfo. So, like most of the times, the fix is easy, but pinpointing the exact problem isn’t.
Don’t forget to restart Nagios after changing the path as
utils.pm needs to be reloaded.
As Ubuntu is based on Debian, I expect this fix to work there as well. According to this Launchpad bug report this issue was fixed in January in version 1.4.16-1ubuntu1 of the nagios-plugins package, which is not in Ubuntu 12.04.