!include my.cnf

[mysqld.1]
gtid-domain-id=1
server-id=1
log-bin
log-slave-updates

[mysqld.2]
gtid-domain-id=2
server-id=2
log-bin
log-slave-updates

[mysqld.3]
gtid-domain-id=3
server-id=3
log-bin
log-slave-updates