Best open source server notification software

I am looking for an open source notification/monitoring software which will work much like growl does with a mac.

It would be awesome if I could receive certain messages to my mac computer from my server when lets say it restarts or some predefined error happens etc.

Anyone know of anything like that?

I know of Nagios but I am thinking not as complex.

Pick any monitoring system you want and, as part of the alert process, have it run a Perl script to send Growl updates to your machines through available libraries (e.g. Net::Growl).

Another option is, if you have an internal Jabber/XMPP server, have the alerts be sent to your chat client, and that that pop things up in Growl (Net::XMPP). Or even Twitter:

http://www.google.com/search?q=cpan+twitter

As it stands, monitoring is an entirely different topic and you need to provide more detail if you want anyone to recommend particular software. Some open source options are

• Nagions
• OpenNMS
• Zabbix
• Mon
• Monit

I'm sure there are others that people can recommend. Search this web site for more information.