What tool do you use to monitor your servers?
I'm a developer in a shop with dozens of Solaris, Linux and Windows servers. Since I'm not a sysadmin I'm posting here to tap that expertise. There are various monitoring needs here and I'm looking for a good solution. Examples of needs include:
- regularly checking how many files are in a directory on a remote server via sftp, or scp, or NFS, or Windows share
- regularly confirming that we can still login to a remote server that we don't control
- regularly running some ad hoc query against a database, and alerting people via email if some criteria is met
- alerting us if a particular string appears in an application log file, e.g. a Java Exception has been thrown
- having robust/flexible scheduling to do all the above
- supporting a variety of languages to write monitoring scripts
- having a diverse set of plugins that allow us to tap new functionality created by the user community
My research so far leads me towards Nagios, however someone has also mentioned Symantec Altiris. Any suggestions or comments about these or other platforms is greatly appreciated.