Check the following document
Also read the following and carefully rethink what you really need and especially why, syncing two installations is not trivial. If you really want everything to be in sync, you need a two way replication supported by your RDBMS and additionally need to sync your Bugzilla installation folder using something like rsync.
But if your really want everything to be the same, why you should sync at all? Just give everyone access to one installation and secure that access properly using firewalls, which would be damn easy.
So chances are you don't really want to keep everything in sync and that's when your trouble starts and you should really consider some other solution like the group controls Bugzilla provides out of the box.
But that would need you to describe your requirements instead what you think is the only solution...