I have previously posted on how to create a WordPress (Multisite) farm on a Bitnami server. A big problem when you manage a farm is keeping all the plug-ins up-to date. Until the release of WordPress 3.9 it was not possible to have single copy of a plug-in in a master version and then symbolically link to it from all other versions.
This is now possible and documented here
I have not tested it yet so if you do please feel free to comment below.