I am using Ubuntu 16.04 and was attempting to build a cluster / mirror server based on the Installing a Web, Email & MySQL Database Cluster on Debian 8 tutorial where all are seemed working but I have a question regarding step 5.5 MySQL Master-Master-Replication. After doing step 5.5, I got the answer for both in master server is yes (as prescribed by the tutorial) but then answer for both in cluster / mirror server is no - so is this the correct situation? Or they should both be running i.e. in master server and cluster server? Thank you in advance.