not an answer really, but some pointers: definitivly take a look at presentation about nagios @ goldman sachs. they faced problems you mention – redundancy, scalability: thousands of hosts, also automated configuration generation. i had redundant nagios setup but at much smaller scale – 80 servers, ~1k services in total. one dedicated master server, one … Read more
Disclaimer: I used to work on that project because I felt it’s extremely powerful. (and i still think so) I use it since 2009ish and have except for legacy setups never touched a “normal” (one may say legacy) Nagios setup again. It would feel like a waste of time. The largest setup I know of … Read more
I did this on my development box by disabling sendmail completely and then having a simple perl script listen on the SMTP port and dump the emails into a directory. I’m sure it’s possible to do with the sendmail configuration, but the perl script was much easier. Here’s it stripped down to the essentials: #!/usr/bin/perl … Read more
I have tried using check_http but I get success even if the website is redirected to an error page This can be solved with check_http –expect. Here is the documentation from check_http –help: -e, –expect=STRING Comma-delimited list of strings, at least one of them is expected in the first (status) line of the server response … Read more
I use the standard NAGIOS check_procs plugin, with the -C flag, shown here being invoked from nrpe.cfg via NRPE: command[check_spamd]=/usr/lib/nagios/plugins/check_procs -c 1: -w 3: -C spamd which will WARN if it doesn’t find at least three processes with the executable name (not counting path) spamd, and which will CRIT if it doesn’t find at least … Read more
Wikipedia has a comparative table which helps a lot I think the key differences are: language: Nagios is written in C and OpenNMS in Java. It makes nagios a lot faster on older hardware. Data collection: Nagios performs very little data collection. Other software (like cacti for example) will be required for a more extensive … Read more
Check out the Nagios FAQ at No permission to view configuration, which says: Description: If you click on “View Config” and you get: “””It appears as though you do not have permission to view the configuration information you requested… If you believe this is an error, check the HTTP server authentication requirements for accessing this … Read more
With a second monitoring server, of course. The second one can be much simpler, since all it needs to do is monitor the first. And it should be monitored by the main monitoring system in turn, of course. If your group is part of a larger organization with separate IT infrastructures, you may be able … Read more
In the left hand column of the Nagios interface (underneath “System”) pick “Downtime”. That takes you to a page listing all scheduled downtime and lets you delete them individually.
Linux load is actually simple. Each of the load avg numbers are the summation of all the core’s avg load. Ie. 1 min load avg = load_core_1 + load_core_2 + … + load_core_n 5 min load avg = load_core_1 + load_core_2 + … + load_core_n 15 min load avg = load_core_1 + load_core_2 + … … Read more