Lock database table backup and master-slave replication

change master to master_host='10.0.20.201',master_user='repl',master_password='123456',master_log_file='mysql-bin.000009',master_log_pos=765407510;

flush tables with read lock;

unlock tables;

mysqldump -uroot -p'xxxx' --set-gtid-purged=off --all-databases > ./all-databases.sql