Implementing SSL on replication is an easy task. The question is: do you need SSL? In a completely local and closed network (and depending on your security restrictions of course), you generally don't need to set SSL as there is no Man In The Middle (MITM) possibility like with VPN.

However, in a nonrestricted, DMZ, or any opened network area, it's strongly recommended to add more security. Also, as database information is generally very important/critical, it could be very problematic if your data gets stolen. The privacy of your data is generally very important, as is the confidentiality. That's why you may think of implementing SSL replication to get uncleared traffic between multiple MariaDB hosts.

SSL will of course introduce network and CPU overhead. This parameter has to be taken into account as well. However, in some cases, like several Cloud providers, you'll have only a public IP per OS instance and you need to establish communication between two Internet-exposed...