一、部署MySQL主从异步复制
三台虚拟机：192.168.200.111（主）
192.168.200.112（从）
192.168.200.113（从）
1、所有虚拟机关闭防火墙及安全机制
[root@localhost ~]# iptables -F
[root@localhost ~]# systemctl stop firewalld
[root@localhost ~]# setenforce 0
2、在主服务器上配置NTP时间同步服务器
[root@localhost ~]# yum -y install ntp
[root@localhost ~]# vim /etc/ntp.conf
server 127.127.1.0
fudge 127.127.1.0 stratum 8
启动NTP服务：
[root@localhost ~]# systemctl enable ntpd
[root@localhost ~]# systemctl start ntpd
3、在两个从服务器上配置与主服务器进行时间同步
[root@localhost ~]# yum -y install ntpdate
[root@localhost ~]# ntpdate 192.168.200.111
15 Oct 12:18:55 ntpdate[38198]: step time server 192.168.200.111 offset -0.569210 sec
4、在所有的服务器上操作安装mariadb和mariadb-server
[root@localhost ~]# yum -y install mariadb mariadb-server
5、配置主服务器
（1）[root@localhost ~]# vim /etc/ntp.conf
disable monitor
server 127.127.1.0
fudge 127.127.1.0 stratum 8
（2）重启服务器：[root@localhost ~]# systemctl restart mariadb
[root@localhost ~]#
（3）创建 Replication用户
[root@localhost ~]# mysql
Welcome to the MariaDB monitor. Commands end with ; or g.
Your MariaDB connection id is 2
Server version: 5.5.41-MariaDB-log MariaDB Server
Copyright (c) 2000, 2014, Oracle, MariaDB Corporation Ab and others.
Type 'help;' or 'h' for help. Type 'c' to clear the current input statement.
MariaDB [(none)]> grant replication slave on *.* to 'myslave'@'192.168.200.11_' identified by '123'；
Query OK, 0 rows affected (0.01 sec)
MariaDB [(none)]> flush privileges;
Query OK, 0 rows affected (0.01 sec)
（4）获得Master DB的相关信息
MariaDB [(none)]> show master status;
+------------------+----------+--------------+------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB |
+------------------+----------+--------------+------------------+
| mysql-bin.000001 | 476 | | |
+------------------+----------+--------------+------------------+
1 row in set (0.00 sec)
备份MySQL原有的数据，如果没有就忽略
6、在两台从服务器上的配置
（1）做一个连接测试：
[root@localhost ~]# mysql -umyslave -p123 -h 192.168.200.111
Welcome to the MariaDB monitor. Commands end with ; or g.
Your MariaDB connection id is 3
Server version: 5.5.41-MariaDB-log MariaDB Server
Copyright (c) 2000, 2014, Oracle, MariaDB Corporation Ab and others.
Type 'help;' or 'h' for help. Type 'c' to clear the current input statement.
MariaDB [(none)]>
（2）修改MySQL配置文件
[root@localhost ~]# vim /etc/my.cnf
relay-log=relay-log-bin
relay-log-index=slave-relay-bin.index
server-id=2
[root@localhost ~]# systemctl restart mariadb
（3）两台从服务器连接MySQL环境
[root@localhost ~]# mysql
Welcome to the MariaDB monitor. Commands end with ; or g.
Your MariaDB connection id is 2
Server version: 5.5.41-MariaDB MariaDB Server
Copyright (c) 2000, 2014, Oracle, MariaDB Corporation Ab and others.
Type 'help;' or 'h' for help. Type 'c' to clear the current input statement.
MariaDB [(none)]> stop slave; //把自己从的角色功能先停掉
Query OK, 0 rows affected, 1 warning (0.00 sec)
MariaDB [(none)]>change master to master_host='192.168.200.111',master_user='myslave',master_password='123',master_log_file='mysql-bin.000001',master_log_pos=2462;
Query OK, 0 rows affected (0.01 sec)
MariaDB [(none)]> start slave;
Query OK, 0 rows affected (0.01 sec)
MariaDB [(none)]> show slave statusG
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.200.111
Master_User: myslave
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000001
Read_Master_Log_Pos: 476
Relay_Log_File: relay-log-bin.000002
Relay_Log_Pos: 529
Relay_Master_Log_File: mysql-bin.000001
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
（4）所有主机执行show databases;结果是一样都有四个库，只在主服务器上创建一个库
MariaDB [(none)]> create database ab_test;
Query OK, 1 row affected (0.00 sec)
MariaDB [(none)]> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| ab_test |
| mysql |
| performance_schema |
| test |
+--------------------+
5 rows in set (0.00 sec)
两台从服务器上也有这个库：
