MySQL 5.7 Release Notes
START GROUP_REPLICATION
Starts Group Replication on this server instance. This statement
requires the SUPER privilege. If
super_read_only=ON and the
member should join as a primary,
super_read_only is set to
OFF once Group Replication successfully
starts.
A server that participates in a group in single-primary mode
should use
skip_replica_start=ON.
Otherwise, the server is not allowed to join a group as a
secondary.