"Gtid mode should be ON for Group Replication" Displayed When Setting Up the MySQL+MGR Single-Primary Mode

Symptom

During the setup of MySQL 8.0.18+MGR single-primary mode, the message "Gtid mode should be ON for Group Replication" is displayed after the START GROUP_REPLICATION; statement is executed.

Key Process and Cause Analysis

A global transaction identifier (GTID) is used to trace transactions in a distributed system. To set up MGR, you need to enable GTID.

Conclusion and Solution

1. Enable and configure MySQL GTID.

   set global enforce_gtid_consistency=ON;
   set global gtid_mode=OFF_PERMISSIVE;
   set global gtid_mode=ON_PERMISSIVE;
   set global gtid_mode=ON;

2. Run the following statement to start MGR:

   START GROUP_REPLICATION;