I have a few servers with the common services running (apache, imap, pop, smtp, ftp, ssh, svn, etc...) and would like to monitor their availability.
In particular, I would like to be alerted (email and/or SMS) if one of the important services dies, and if possible to get some basic stats about each services (number of connections, number of email processed, spam ratio, etc..).
This tool would be used both by us to get real-time status and alerts, and by our savy customers that want to get an overview of what is going on.
I could build myself a simple webapp that does that ("pinging" the services to see if they're alive), or I could also use a full-fledged monitoring tool (nagios for instance, but a bit overkill no?), but I'm sure there exists something in between that would fit my needs.
Any recommendation ? If possible, the ideal solution would be free, easy to install on a remote server (not even in the same subnet) and if possible have an eye-candy interface ;).