一、查看两台主机的版本Ubuntu 16.04.3
root@iZ2zeht3zvxbq5ycy698pwZ:~# lsb_release -a
LSB Version: core-9.20160110ubuntu0.2-amd64:core-9.20160110ubuntu0.2-noarch:security-9.20160110ubuntu0.2-amd64:security-9.20160110ubuntu0.2-noarch
Distributor ID: Ubuntu
Description: Ubuntu 16.04.3 LTS
Release: 16.04
Codename: xenial
root@iZ2zeht3zvxbq5ycy698pwZ:~# 二、查看mysql的版本
mysql> select version();
+-------------------------+
| version() |
+-------------------------+
| 5.7.21-0ubuntu0.16.04.1 |
+-------------------------+
1 row in set (0.00 sec)
mysql> 三、以39.107.227.105当主机，39.107.116.135当从机
先登录主机 A，在主服务器上，设置一个从数据库的账户，使用REPLICATION SLAVE（从复制）赋予权限，如：
mysql> GRANT REPLICATION SLAVE ON *.* TO 'backup'@'39.107.116.135' IDENTIFIED BY '123456';
Query OK, 0 rows affected, 1 warning (0.00 sec)
mysql> 刷新权限
mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)
mysql> 如果有多台主机，就需要执行多次
四、（这个方法不要用，请看第五步）(坑，这是个坑，mysql5.7版本的改了my.cnf根本就无法使用)打开主机A的my.cnf，输入如下：（修改主数据库的配置文件my.cnf，开启BINLOG，并设置server-id的值，修改之后必须重启mysql服务），位于/etc/mysql下的my.cnf
server-id = 1 #主机标示，整数
log_bin = /var/log/mysql/mysql-bin.log #确保此文件可写，开启bin-log
read-only =0 #主机，读写都可以
binlog-do-db =test #指定mysql的binlog日志记录哪个db,多个写多行
binlog-ignore-db =mysql #不需要备份的数据库，多个写多行注意：如果要让mysql监听到其他的地址，可以将bind-address = 127.0.0.1注释掉。
或者将bind-address = 0.0.0.0监听所有的地址
1. 如果不按照如上所述设置，会报出错误信息：MYSQL ERROR 2003 (HY000): Can’t connect to MySQL server on ‘192.168.1.X’ (111)
2. 如果按照如上所述设置，报出错误信息：Host ‘192.168.1.X’ is not allowed to connect to this MySQL server ，那么请检查数据库账号的权限是否有问题。五、mysql5.7版本的请修改，/etc/mysql/mysql.conf.d，以下mysqld.cnf文件的配置
root@iZ2zeht3zvxbq5ycy698pwZ:/etc/mysql/mysql.conf.d# pwd
/etc/mysql/mysql.conf.d使用vi编辑mysqld.cnf
# The following can be used as easy to replay backup logs or for replication.
# note: if you are setting up a replication slave, see README.Debian about
# other settings you may need to change.
#
server-id = 1
log_bin = /var/log/mysql/mysql-bin.log
expire_logs_days = 10
max_binlog_size = 100M
binlog_do_db = test (这个地方是指定同步的数据库)
binlog_ignore_db = mysql（这个地方指定不同步的数据库）六、重启一下mysql
root@iZ2zeht3zvxbq5ycy698pwZ:~# service mysql restart七、通过以下命令验证二进制日志是否已经启动
mysql> show variables like 'log_%';
+----------------------------------------+--------------------------------+
| Variable_name | Value |
+----------------------------------------+--------------------------------+
| log_bin | ON |
| log_bin_basename | /var/log/mysql/mysql-bin |
| log_bin_index | /var/log/mysql/mysql-bin.index |
| log_bin_trust_function_creators | OFF |
| log_bin_use_v1_row_events | OFF |
| log_builtin_as_identified_by_password | OFF |
| log_error | /var/log/mysql/error.log |
| log_error_verbosity | 3 |
| log_output | FILE |
| log_queries_not_using_indexes | OFF |
| log_slave_updates | OFF |
| log_slow_admin_statements | OFF |
| log_slow_slave_statements | OFF |
| log_statements_unsafe_for_binlog | ON |
| log_syslog | OFF |
| log_syslog_facility | daemon |
| log_syslog_include_pid | ON |
| log_syslog_tag | |
| log_throttle_queries_not_using_indexes | 0 |
| log_timestamps | UTC |
| log_warnings | 2 |
+----------------------------------------+--------------------------------+
21 rows in set (0.01 sec)八、mysql从库配置(135的那台机)，mysql5.7版本的请修改，/etc/mysql/mysql.conf.d，以下mysqld.cnf文件的配置
从库只需要开启server-id就行了 
如果要设置多个从库，则每个从库的server-id与主库和其他从库设置不同的唯一值。
九、mysql重启一下
root@iZ2ze451u03knf2sumyavyZ:~# service mysql restart十、配置主从库之间的通信
（105的那台机）查看 Master-Server ， binlog File 文件名称和 Position值位置 并且记下来
mysql> show master status;
+------------------+----------+--------------+------------------+-------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+-------------------+
| mysql-bin.000001 | 2021 | test | mysql | |
+------------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)
mysql> 十一、要设置从库（135机）与主库（105机）进行通信，进行复制，使用必要的连接信息配置从库在从库上（135机）执行以下语句
将选项值替换为与系统相关的实际值
参数格式，请勿执行
mysql> CHANGE MASTER TO
-> MASTER_HOST='master_host_name',
-> MASTER_USER='replication_user_name',
-> MASTER_PASSWORD='replication_password',
-> MASTER_LOG_FILE='recorded_log_file_name',
-> MASTER_LOG_POS=recorded_log_position;请将参数修改成符合你自己的，再执行
mysql> CHANGE MASTER TO
-> MASTER_HOST='39.107.227.105',
-> MASTER_USER='backup',
-> MASTER_PASSWORD='123456',
-> MASTER_LOG_FILE='mysql-bin.000001',
-> MASTER_LOG_POS=2021;
Query OK, 0 rows affected, 2 warnings (0.03 sec)
mysql> 下面这个参数对应于上图的Position
MASTER_LOG_POS=0 写成0 也是可以的放在一行用逗号隔开，也是可以的
mysql> CHANGE MASTER TO MASTER_HOST='192.168.252.123', MASTER_USER='replication', MASTER_PASSWORD='mima', MASTER_LOG_FILE='mysql-bin.000001', MASTER_LOG_POS=629;十二、（135机）启动从数据库复制线程
mysql> START SLAVE;
Query OK, 0 rows affected (0.01 sec)
mysql> 十三、（135机）查看复制状态
show slave status\G
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 39.107.227.105
Master_User: backup
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000001
Read_Master_Log_Pos: 2021
Relay_Log_File: iZ2ze451u03knf2sumyavyZ-relay-bin.014660
Relay_Log_Pos: 320
Relay_Master_Log_File: mysql-bin.000001
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
Replicate_Do_DB:
......十四、（135）检查主从复制通信状态 
Slave_IO_State #从站的当前状态
Slave_IO_Running： Yes #读取主程序二进制日志的I/O线程是否正在运行
Slave_SQL_Running： Yes #执行读取主服务器中二进制日志事件的SQL线程是否正在运行。与I/O线程一样
Seconds_Behind_Master #是否为0，0就是已经同步了如果不是：
主要有以下 4 个方面：
1、网络不通
2、密码不对
3、MASTER_LOG_POS 不对 ps
4、mysql 的 auto.cnf server-uuid 一样（可能你是复制的mysql）
第4问题可照一下操作
root@iZ2ze451u03knf2sumyavyZ:~# find / -name 'auto.cnf'
/var/lib/mysql/auto.cnf
quit
^C
root@iZ2ze451u03knf2sumyavyZ:~# vi /var/lib/mysql/auto.cnfserver-uuid=6b831bf3-8ae7-11e7-a178-000c29cb5cbc # 按照这个16进制格式，修改server-uuid，重启mysql service mysql restart ，并开启从库同步即可root@iZ2ze451u03knf2sumyavyZ:~# service mysql restart
root@iZ2ze451u03knf2sumyavyZ:~# mysql -uroot -p
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 5
Server version: 5.7.21-0ubuntu0.16.04.1 (Ubuntu)
Copyright (c) 2000, 2018, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> START SLAVE
-> quit;
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'quit' at line 2
mysql> START SLAVE;
Query OK, 0 rows affected, 1 warning (0.00 sec)十五：通过第十步，查看到master是指定了同步的数据库和不同步的数据库。
那么我们现在不想指定这两个参数。
1.只需要回去将那两个变量给注释掉：
root@iZ2zeht3zvxbq5ycy698pwZ:/etc/mysql/mysql.conf.d# ls
mysqld.cnf mysqld_safe_syslog.cnf
root@iZ2zeht3zvxbq5ycy698pwZ:/etc/mysql/mysql.conf.d# vi mysqld.cnf2.重启主库（105机）
root@iZ2zeht3zvxbq5ycy698pwZ:/etc/mysql/mysql.conf.d# service mysql restart3.登陆主库（105），查看主库状态
mysql> show master status;
+------------------+----------+--------------+------------------+-------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+-------------------+
| mysql-bin.000002 | 154 | | | |
+------------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)
4.登陆从库（135），从新配置跟随的主库信息
先停止线程
mysql> Stop SLAVE;
Query OK, 0 rows affected (0.01 sec)在从库（135中）配置同步主库（105）
mysql> CHANGE MASTER TO MASTER_HOST='39.107.227.105', MASTER_USER='backup', MASTER_PASSWORD='123456', MASTER_LOG_FILE='mysql-bin.000002', MASTER_LOG_POS=154;
Query OK, 0 rows affected, 2 warnings (0.01 sec)5.启动从库同步线程
mysql> START SLAVE;
Query OK, 0 rows affected (0.01 sec)十五、测试主从同步情况
1.在主库中（105）在 Master-Server 创建测试库，使用创建的测试库，并创建表
mysql> CREATE DATABASE `replication_wwww.ymq.io`;
Query OK, 1 row affected (0.00 sec)
mysql> use `replication_wwww.ymq.io`;
Database changed
mysql> CREATE TABLE `sync_test` (`id` int(11) NOT NULL AUTO_INCREMENT, `name` varchar(255) NOT NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8;
Query OK, 0 rows affected (0.02 sec)
mysql> 2.查看从库（135机）Slave-Server 查看是否同步过来
mysql> show databases
-> ;
+-------------------------+
| Database |
+-------------------------+
| information_schema |
| mysql |
| performance_schema |
| replication_wwww.ymq.io |
| sys |
+-------------------------+
5 rows in set (0.00 sec)
mysql> 同步完成。
后记：搞技术要的就是耐心和解决问题的能力，不要急，一步步慢慢来，祝您成功。
