"The group communication engine is not ready for the member to join" 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 "The group communication engine is not ready for the member to join" is displayed after the START GROUP_REPLICATION; statement is executed.

Key Process and Cause Analysis

When starting group replication for the first time, set group_replication_bootstrap_group to ON.

Conclusion and Solution

1. Run the following statement on the primary node to enable the boot group mode in MGR and set group_replication_bootstrap_group to ON:

   SET GLOBAL group_replication_bootstrap_group=ON;

2. Run the following statement to start MGR:

   START GROUP_REPLICATION;

3. Restore the setting of group_replication_bootstrap_group to OFF.

   SET GLOBAL group_replication_bootstrap_group=OFF;