The first question to consider is: do you use one already or are you required to use a specific one? If the answer to that question is yes, then you should likely implement that rather than adding a new server to run Vitess. However, in large implementations, it makes sense to run a separate topology server dedicated to Vitess. This avoids "noisy neighbor" problems.

By default, we recommend that you use etcd if you can, otherwise you may use ZooKeeper.