yum

MYSQL主从复制环境构建至少需2台服务器，可以配置1主多从，多主多从，本实验为1主1从，实验步骤如下：

Master：192.168.133.134
Slave： 192.168.133.135

$ systemctl stop firewalld
$　setenforce 0
$ vi /etc/selinux/config

# This file controls the state of SELinux on the system.
# SELINUX= can take one of these three values:
#     enforcing - SELinux security policy is enforced.
#     permissive - SELinux prints warnings instead of enforcing.
#     disabled - No SELinux policy is loaded.
SELINUX=disabled  enforcing-->disabled
# SELINUXTYPE= can take one of three values:
#     targeted - Targeted processes are protected,
#     minimum - Modification of targeted policy. Only selected processes are protected.
#     mls - Multi Level Security protection.
SELINUXTYPE=targeted

$　yum install mariadb mariadb-server epel-release net-tools -y

$ systemctl start mariadb

$ systemctl  enable  mariadb      

$ netstat -nltp;ps -ef|grep  mysql 

Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name    
tcp        0      0 0.0.0.0:3306            0.0.0.0:*               LISTEN      9618/mysqld    
tcp        0      0 0.0.0.0:111             0.0.0.0:*               LISTEN      1/systemd           
tcp        0      0 0.0.0.0:6000            0.0.0.0:*               LISTEN      7527/X              
tcp        0      0 192.168.122.1:53        0.0.0.0:*               LISTEN      7258/dnsmasq        
tcp        0      0 0.0.0.0:22              0.0.0.0:*               LISTEN      6862/sshd           
tcp        0      0 127.0.0.1:631           0.0.0.0:*               LISTEN      6865/cupsd          
tcp        0      0 127.0.0.1:25            0.0.0.0:*               LISTEN      7268/master         
tcp6       0      0 :::111                  :::*                    LISTEN      1/systemd           
tcp6       0      0 :::6000                 :::*                    LISTEN      7527/X              
tcp6       0      0 :::22                   :::*                    LISTEN      6862/sshd           
tcp6       0      0 ::1:631                 :::*                    LISTEN      6865/cupsd          
tcp6       0      0 ::1:25                  :::*                    LISTEN      7268/master         
mysql      9453      1  0 20:32 ?        00:00:00 /bin/sh /usr/bin/mysqld_safe --basedir=/usr
mysql      9618   9453  0 20:32 ?        00:00:00 /usr/libexec/mysqld --basedir=/usr --datadir=/var/lib/mysql --plugin-dir=/usr/lib64/mysql/plugin --log-error=/var/log/mariadb/mariadb.log --pid-file=/var/run/mariadb/mariadb.pid --socket=/var/lib/mysql/mysql.sock
root       9732   9198  0 20:37 pts/1    00:00:00 grep --color=auto mysql

在[mysqld]下面添加如下代码：

server-id=1        #数据库唯一ID，主从的标识号绝对不能重复,master端server-id与slave端不一样即可，相当于身份id

log-bin=mysql-bin    #开启bin-log，并指定文件目录和文件名前缀，记录执行的sql语句，相当于日志功能

binlog-ignore-db=mysql  #不同步的系统数据库。如果是多个不同步库，就以此格式另写几行；也可以在一行，中间逗号隔开

sync_binlog = 1      #确保binlog日志写入后与硬盘同步

binlog_checksum = none  #跳过现有的采用checksum的事件，mysql5.6.5以后的版本中binlog_checksum=crc32,而低版本都是binlog_checksum=none

binlog_format = mixed   #bin-log日志文件格式，设置为MIXED可以防止主键重复

配置文件修改完记得重启mysql
$ systemctl restart mariadb
如果无法正常启动报错如下：
Job for mariadb.service failed because the control process exited with error code. See “systemctl status mariadb.service” and “journalctl -xe” for details.
执行如下命令解决：
$ cd /var/lib/mysql
$ mv ib_logfile0 ib_logfile0.bak
$ mv ib_logfile1 ib_logfile1.bak
应该就行了

# 进入Master数据库
$ mysql 
# 只允许192.168.133.135使用root用户，且密码为"fcz123"连接主库做数据同步
$ grant replication slave,replication client on *.* to root@'192.168.33.135' identified by "fcz123";
# 允许所有使用root用户,密码为"fcz123"连接主库做数据同步
$ grant replication slave,replication client on *.* to root@'%' identified by "fcz123";
# 设置数据库密码
$ set password for 用户名@localhost = password('新密码'); 
# 刷新权限
$　flush privileges;
# 权限查看
$ show grants;
$ show grants for root@'192.168.133.135';

# 锁定数据库
$ flush tables with read lock; 
# 查看数据库状态
$ show master status;
# 创建目录
$ mkdir /fcz
# 导出需要同步的库
$ mysqldump -uroot -p'' -S /var/lib/mysql/mysql.sock --events -A -B |gzip >/fcz/mysql_back.$(date +%F).sql.gz
Enter password: 输入数据库密码
# 解除锁定
$ unlock tables ;

在[mysqld]下面添加如下代码：

server-id=2   #设置从服务器id，必须于主服务器不同

replicate-ignore-db=mysql  #不同步的数据库

slave-skip-errors = all   #跳过所有的错误，继续执行复制操作

配置文件修改完记得重启mysql
$ systemctl restart mariadb

$ cd /fcz
$ scp mysql_back.2022-05-18.sql.gz root@192.168.133.135:/fcz

#进入Slave数据库
$ mysql
＃执行同步前，要先关闭slave
$ stop slave;   
#需要和主数据库的show master status命令结果保持一致
$ change master to master_host='Master_ip',master_user='用户名',master_password='密码',master_log_file='File',master_log_pos=Position;
# 启动Slave端
$ start slave;
# 查询数据库状态
$ show slave status G;

找到下面这两行,如果都为Yes,那么恭喜你主从同步配置成功
Slave_IO_Running: Yes
Slave_SQL_Running: Yes

主库创建数据库

从库查看数据库