概述：
原理：
搭建：
实践
1.首先准备俩台安装MySQL的纯净服务器
俩台服务器都做如下操作：
同步时间，修改时区
#ntpdate time.windows.com
#timedatectl set-timezero Asia/Shanghai
修改主机名
#hostnamectl set-hostname zhuku
#hostnamectl set-hostname congku
配置静态ip
# vim /etc/sysconfig/network-scripts/ifcfg-ens33
将dhcp改为static
IPADDR=本机ip
GATEWAY=192.168.231.2
NETMASK=255.255.255.0
DNS1=114.114.114.114
DNS2=8.8.8.8清理环境在安装MySQL之前
俩台服务器都需要做的操作
[root@slave ~]#yum -y erase `rpm -qa | grep -E "mysql|mariadb"`
[root@slave ~]# rm -rf /etc/my* /var/lib/mysql* /var/log/mysql*
#检查一下，环境清理干净没有
[root@slave ~]# [[ ! -f /etc/my.cnf ]] && [[ ! -d /var/lib/mysql ]] && [[ ! -f /usr/bin/mysql ]] && echo "数据库已清除" || echo "数据库未清理"安装mysql
启动服务：
# systemctl start mysqld
寻找密码
grep password /var/log/mysqld.log
也可以
mysqladmin -p"`awk '/temporary password/{p=$NF}END{print p}' /var/log/mysqld.log`" password 'Qianfeng@123'
这条命令是直接登录MySQL，顺便将密码修改以后 可以登录
也可以是,获取新的MySQL的密码
# awk '/temporary password/{p=$NF}END{print p}' /var/log/mysqld.log2.配置主库：
创建日志目录并赋予权限
# mkdir /var/log/mysql
# chown -R mysql.mysql /var/log/mysql编辑主库服务器的配置文件 /etc/my.cnf
[mysqld]
log-bin=/var/log/mysql/mysql-bin #启用二进制文件日志记录
server-id=1 # 服务id，保证整个集群环境唯一
read-only=0 #1是只读，0是读写重启服务
# systemctl restart mysqld在主库登录MySQL，创建用户
为了用户在从库中用来连接主库的账号
mysql> grant replication slave on *.* to '用户名'@'ip' identified by '密码';
这是为用户分配主从复制的权限，并创建用户
刷新：
mysql> flush privileges;查看二进制日志坐标
mysql> show master status;
+------------------+----------+--------------+------------------+-------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+-------------------+
| mysql-bin.000001 | 313 | | | |
+------------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)
3.配置从库
编辑从库服务器的配置文件my.cnf
[mysqld]
server-id=2
read-only=1 #普通用户一般只有只读，可以不写重启mysql服务
# systemctl restart mysqld登录mysql
此处登录的是你从库mysql的root用户登录的账号与密码，不是在主库创建的用户
mysql> change master to master_host='主库的ip'，
master_user='连接主库用户名',
master_password='连接主库用户的密码',
master_log_file='日志文件名',
mastre_log_pos='日志位置';
日志位置就是在主库show master status查出来那个数字 ----313
+------------------+----------+--------------+------------------+-------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+-------------------+
| mysql-bin.000001 | 313 | | | |
+------------------+----------+--------------+------------------+-------------------+
当你第一次记不住这么多命令时，可以直接
mysql > ? change master to
出现下列，直接复制
CHANGE MASTER TO
MASTER_HOST='source2.example.com',
MASTER_USER='replication',
MASTER_PASSWORD='password',
MASTER_PORT=3306,
MASTER_LOG_FILE='source2-bin.001',
MASTER_LOG_POS=4,
MASTER_CONNECT_RETRY=10;
然后： mysql > ?e
进入文本编辑器内，将复制的 内容进行修改 然后保存即可启动：
mysql> start slave;查看主从同步状态：
mysql> show slave status\G
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 192.168.231.153 -----主库的ip
Master_User: itcast -----用来连接主库的用户名
Master_Port: 3306 ------端口
Connect_Retry: 60
Master_Log_File: mysql-bin.000001 -----二进制日志名字
Read_Master_Log_Pos: 313
Relay_Log_File: congku-relay-bin.000002 -----中继日志名字
Relay_Log_Pos: 479
Relay_Master_Log_File: mysql-bin.000001
Slave_IO_Running: Yes --------主要看俩个IO线程是否成功启动
Slave_SQL_Running: Yes --------看SQL线程是否成功启动
Replicate_Do_DB:
Replicate_Ignore_DB:
Replicate_Do_Table:
Replicate_Ignore_Table:
4.测试主从复制
主库！
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| company |
| db1 |
| mysql |
| performance_schema |
| school |
| sys |
| xian |
+--------------------+
8 rows in set (0.00 sec)
从库：
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| sys |
| xian |
+--------------------+
5 rows in set (0.00 sec)
!!!!在主库创建库，创建表，写入数据
mysql> create database db2;
mysql> create table db2.zhucong(id int,name varchar(50),age int);
mysql> insert into zhucong(id,name,age) values(1,'aaa',18),
values(2,'bbb',19) ,(3,'ccc',20);
mysql> select * from zhucong;
+------+------+------+
| id | name | age |
+------+------+------+
| 1 | aaa | 18 |
| 2 | bbb | 19 |
| 3 | ccc | 20 |
+------+------+------+
3 rows in set (0.00 sec)
!!!在从库查看
mysql> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| db2 |
| mysql |
| performance_schema |
| sys |
| xian |
+--------------------+
mysql> use db2;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Database changed
mysql> show tables;
+---------------+
| Tables_in_db2 |
+---------------+
| zhucong |
+---------------+
1 row in set (0.00 sec)
mysql> select * from zhucong;
+------+------+------+
| id | name | age |
+------+------+------+
| 1 | aaa | 18 |
| 2 | bbb | 19 |
| 3 | ccc | 20 |
+------+------+------+
修改主库中的表数据，查看从库是否有变化
主库：
mysql> update zhucong set age=21;
Query OK, 3 rows affected (0.00 sec)
Rows matched: 3 Changed: 3 Warnings: 0
mysql> select * from zhucong;
+------+------+------+
| id | name | age |
+------+------+------+
| 1 | aaa | 21 |
| 2 | bbb | 21 |
| 3 | ccc | 21 |
+------+------+------+
3 rows in set (0.00 sec)
查看从库：
mysql> select * from zhucong;
+------+------+------+
| id | name | age |
+------+------+------+
| 1 | aaa | 21 |
| 2 | bbb | 21 |
| 3 | ccc | 21 |
+------+------+------+
3 rows in set (0.00 sec)
附加：
获取本机的uuid
[root@slave ~]# uuidgen
b392cd4c-9e3d-4596-9a72-0805c2162c8f
修改本机的uuid
# vim /var/lib/mysql/auto.cnfbase64加密与解密
[root@slave mysql]# echo “马龙” | base64
4oCc6ams6b6Z4oCdCg==
[root@slave mysql]# echo "4oCc6ams6b6Z4oCdCg==" | base64 -d
“马龙”
