Ubuntu Servers :: Synchronizing Users Across Servers?

I wonder if other people have this problem. sometimes I need to duplicate most or all of a server from one machine to another. part where I most tend to have issues is with recreating the users. Sometimes the UIDs don't match up because of differences between the two systems, which gives funky results, like files owned by the wrong user.

Or, sometimes, I just need to create the same 10 users on x number of machines, and it's tedious to do this 10x times. Plus, then, if you need to change a password or delete a user, you have to do it x times.Any recommendations on how to centralize users/auth?