Advanced MySQL 8

Single primary mode

This is the default configuration mode, which makes a single member act as a writeable master (primary), and the rest of the members act as hot-standbys (secondaries):

Election of primary the group itself coordinates automatically to figure out which member will act as the primary, through a primary election mechanism. For advanced users, you can specify weights to the members of the group. Upon loss of the primary member, the weight will be considered when electing the primary.

Use group_replication_member_weight to set the weight for each of the members. You can set the weight from 0 to 100. The member with the maximum weight gets priority. If you have more than one member with the same weight, then the algorithms sort ...