Lately I've been looking into setting up monitoring and configuration managment on our servers (3 physical, 1 with several virtual servers).
Currently on one server there is Zabbix installed, some have Munin (these monitoring systems have been unmaintained), but uniform monitoring software is not available. Also a centralised configuration manager is not available, and would be a major improvement towards maintainance.
After some reading I've come up with Nagios or Zabbix in combination of either Puppet or Cfengine. However I have no experience with either of these.
In our case it would be best to use understandable and (relatively) easy to deploy software, as due to the structure of the organisation, the IT responsibles change (almost) every year. It should also be able to track down performance pipeline (using graphs on memory or CPU usage for example).
All systems are Linux servers, but if possible it would be nice to have the option to include our Windows PCs in the future.
What option would be best in this case?
EDIT: Another requirement is the solution being free (preferably) open source, as we cannot afford a 2K annual licence fee.