First of, I'm fairly new to this whole linux thing... So be gentle.
I have a couple of Ubuntu servers... A pair of DNS servers running Bind, and a pair of servers running Nginx and HAProxy to load-balance requests to some back-end servers.
Now, the Bind servers pretty much keep each other up to date by doing zone transfers, although there are some settings in bind that I would like to share between them. However, The load-balancer servers are completely independent which is really bad. This is bad because I then have to change the configurations on both servers independently when I want to make config changes. This of course opens the servers up for mistakes where I accidentally configure the two servers differently, which will inevitably turn into "hard to debug" errors and bugs at some point.
So my question is... How do I sync config changes between the servers, as well as automatically restart the services when their configuration changes?