1.理解MySQL主从复制原理

主服务器开启binlog日志，从库生成log dump线程，将binlog日志传给从库I/O线程，从库生成俩个线程，一个是I/O线程，一个是SQL线程，I/O线程去请主库的binlog日志，并将binlog日志中的文件写入relay log中，sql线程会读取relay log 中的内容，并解析成具体的操作，来实现主从一致，达到最终数据一致的目的。

2.完成MySQL主从复制（一主两从）

环境准备：

数据库准备：

create database company;
use company
CREATE TABLE `emp`  (
  `empno` int(4) NOT NULL,
  `ename` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL,
  `job` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL,
  `mgr` int(4) NULL DEFAULT NULL,
  `hiredate` date NOT NULL,
  `sai` int(255) NOT NULL,
  `comm` int(255) NULL DEFAULT NULL,
  `deptno` int(2) NOT NULL,
  PRIMARY KEY (`empno`) USING BTREE
) ENGINE = InnoDB CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = Dynamic;

INSERT INTO `emp` VALUES (1001, '甘宁', '文员', 1013, '2000-12-17', 8000, NULL, 20);
INSERT INTO `emp` VALUES (1002, '黛绮丝', '销售员', 1006, '2001-02-20', 16000, 3000, 30);
INSERT INTO `emp` VALUES (1003, '殷天正', '销售员', 1006, '2001-02-22', 12500, 5000, 30);
INSERT INTO `emp` VALUES (1004, '刘备', '经理', 1009, '2001-04-02', 29750, NULL, 20);
INSERT INTO `emp` VALUES (1005, '谢逊', '销售员', 1006, '2001-09-28', 12500, 14000, 30);
INSERT INTO `emp` VALUES (1006, '关羽', '经理', 1009, '2001-05-01', 28500, NULL, 30);
INSERT INTO `emp` VALUES (1007, '张飞', '经理', 1009, '2001-09-01', 24500, NULL, 10);
INSERT INTO `emp` VALUES (1008, '诸葛亮', '分析师', 1004, '2007-04-19', 30000, NULL, 20);
INSERT INTO `emp` VALUES (1009, '曾阿牛', '董事长', NULL, '2001-11-17', 50000, NULL, 10);
INSERT INTO `emp` VALUES (1010, '韦一笑', '销售员', 1006, '2001-09-08', 15000, 0, 30);
INSERT INTO `emp` VALUES (1011, '周泰', '文员', 1006, '2007-05-23', 11000, NULL, 20);
INSERT INTO `emp` VALUES (1012, '程普', '文员', 1006, '2001-12-03', 9500, NULL, 30);
INSERT INTO `emp` VALUES (1013, '庞统', '分析师', 1004, '2001-12-03', 30000, NULL, 20);
INSERT INTO `emp` VALUES (1014, '黄盖', '文员', 1007, '2002-01-23', 13000, NULL, 10);
INSERT INTO `emp` VALUES (1015, '张三', '保洁员', 1001, '2013-05-01', 80000, 50000, 50);

方式一：基于三台服务器实现主从复制

主库配置：

1、在mysqld标签下添加server_id并开启bin_log日志

[root@node01 ~]# cat /etc/my.cnf
[mysqld]
log_bin=mysql_bin
server_id=1

2、重启数据库服务

[root@node01 ~]# systemctl restart mysqld.service

3、授权同步账号和密码

mysql> grant replication slave on *.* to 'rep'@'192.168.11.%' identified by '123456';
Query OK, 0 rows affected, 1 warning (0.00 sec)

4、查看授权信息

mysql> show grants for 'rep'@'192.168.11.%';
+--------------------------------------------------------+
| Grants for rep@192.168.11.%                            |
+--------------------------------------------------------+
| GRANT REPLICATION SLAVE ON *.* TO 'rep'@'192.168.11.%' |
+--------------------------------------------------------+
1 row in set (0.00 sec)

5、对表操作

# 锁表设置为只读
# 为后边备份准备，注意生产环境要提前申请停机时间，停服
mysql> flush tables with read lock;

# 超过时间不操作会自动解锁，查看超时时间
mysql> show variables like '%timeout%';
+-----------------------------+----------+
| Variable_name               | Value    |
+-----------------------------+----------+
| connect_timeout             | 10       |
| delayed_insert_timeout      | 300      |
| have_statement_timeout      | YES      |
| innodb_flush_log_at_timeout | 1        |
| innodb_lock_wait_timeout    | 50       |
| innodb_rollback_on_timeout  | OFF      |
| interactive_timeout         | 28800    |
| lock_wait_timeout           | 31536000 |
| net_read_timeout            | 30       |
| net_write_timeout           | 60       |
| rpl_stop_slave_timeout      | 31536000 |
| slave_net_timeout           | 60       |
| wait_timeout                | 28800    |
+-----------------------------+----------+
13 rows in set (0.01 sec)

# 查看主库状态
mysql> show master status ;
+------------------+----------+--------------+------------------+-------------------+
| File             | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+-------------------+
| mysql_bin.000001 |    11824 |              |                  |                   |
+------------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)

6、备份数据库数据

# 创建备份目录
[root@node01 ~]# mkdir /server/backup -p

[root@node01 ~]# mysqldump -uroot -p -A -B | gzip > /server/backup/mysql_bak.$(date +%F).sql.gz
Enter password:

7、解锁

mysql> unlock tables;
Query OK, 0 rows affected (0.00 sec)

8、主库备份数据传送到从库

# 在从库上常见备份目录
[root@node02 ~]# mkdir /server/backup -p

# scp传送
[root@node01 ~]# scp /server/backup/mysql_bak.2023-03-25.sql.gz  192.168.11.111:/server/backup/
[root@node01 ~]# scp /server/backup/mysql_bak.2023-03-25.sql.gz  192.168.11.112:/server/backup/

从库配置：

1、关闭bin_log参数，设置server-id

[root@node02 ~]# cat /etc/my.cnf
[mysqld]
datadir=/usr/local/mysql/data
socket=/tmp/mysql.sock
server_id=2

2、重启数据库服务

[root@node02 ~]# systemctl restart mysqld.service

3、还原从主库传输过来的数据文件

[root@node02 ~]# cd /server/backup/
[root@node02 backup]# gzip -d mysql_bak.2023-03-25.sql.gz
[root@node02 backup]# mysql -uroot -p < mysql_bak.2023-03-25.sql
Enter password:

4、检查数据完整性

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| company            |
| mysql              |
| performance_schema |
| sys                |
+--------------------+
5 rows in set (0.00 sec)

mysql> use company;
mysql> select * from company;
# 数据完整，恢复完成

5、配置主从同步

# 查看主库的binlog和pos位置点
mysql> show master status;
+------------------+----------+--------------+------------------+-------------------+
| File             | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+-------------------+
| mysql_bin.000001 |    11824 |              |                  |                   |
+------------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)

# 从库上配置
mysql> change master to
    -> master_host='192.168.11.110',
    -> master_user='rep',
    -> master_password='123456',
    -> master_log_file='mysql_bin.000001',
    -> master_log_pos=11824;
Query OK, 0 rows affected, 2 warnings (0.01 sec)

6、启动从库同步并检查状态

mysql> start slave;
Query OK, 0 rows affected (0.00 sec)

mysql> show slave status \G
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: 192.168.11.110
                  Master_User: rep
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: mysql_bin.000001
          Read_Master_Log_Pos: 11824
               Relay_Log_File: node02-relay-bin.000002
                Relay_Log_Pos: 320
        Relay_Master_Log_File: mysql_bin.000001
             Slave_IO_Running: Yes
            Slave_SQL_Running: Yes
# 看目前最后俩行是否为YES，俩个线程都为YES才OK

测试：

1、主库创建一个数据库

mysql> create database test_master;
Query OK, 1 row affected (0.00 sec)

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| company            |
| mysql              |
| performance_schema |
| sys                |
| test_master        |
+--------------------+
6 rows in set (0.00 sec)

2、从库检查

[root@node02 backup]# mysql -uroot  -p -e 'show databases;'
Enter password:
+--------------------+
| Database           |
+--------------------+
| information_schema |
| company            |
| mysql              |
| performance_schema |
| sys                |
| test_master        |
+--------------------+

第二台从库一样的配置，除了server_id不同

方式二：基于docker实现主从复制

环境准备：

安装docker环境：

# step 1: 安装必要的一些系统工具
sudo yum install -y yum-utils device-mapper-persistent-data lvm2
# Step 2: 添加软件源信息
sudo yum-config-manager --add-repo https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo
# Step 3
sudo sed -i 's+download.docker.com+mirrors.aliyun.com/docker-ce+' /etc/yum.repos.d/docker-ce.repo
# Step 4: 更新并安装Docker-CE
sudo yum makecache fast
sudo yum -y install docker-ce
# Step 4: 开启Docker服务
sudo service docker start

# 注意：
# 官方软件源默认启用了最新的软件，您可以通过编辑软件源的方式获取各个版本的软件包。例如官方并没有将测试版本的软件源置为可用，您可以通过以下方式开启。同理可以开启各种测试版本等。
# vim /etc/yum.repos.d/docker-ce.repo
#   将[docker-ce-test]下方的enabled=0修改为enabled=1
#
# 安装指定版本的Docker-CE:
# Step 1: 查找Docker-CE的版本:
# yum list docker-ce.x86_64 --showduplicates | sort -r
#   Loading mirror speeds from cached hostfile
#   Loaded plugins: branch, fastestmirror, langpacks
#   docker-ce.x86_64            17.03.1.ce-1.el7.centos            docker-ce-stable
#   docker-ce.x86_64            17.03.1.ce-1.el7.centos            @docker-ce-stable
#   docker-ce.x86_64            17.03.0.ce-1.el7.centos            docker-ce-stable
#   Available Packages
# Step2: 安装指定版本的Docker-CE: (VERSION例如上面的17.03.0.ce.1-1.el7.centos)
# sudo yum -y install docker-ce-[VERSION]

1、运行三个容器，mysql01 mysql02 mysql03

# 重启docker服务
[root@template ~]# systemctl restart docker.service

# 拉取镜像
[root@template ~]# docker run --name mysql01 -p 3306:3306 -e MYSQL_ROOT_PASSWORD=123456 -d mysql:5.7 --lower_case_table_names=1
[root@template ~]# docker run --name mysql02 -p 3307:3306 -e MYSQL_ROOT_PASSWORD=123456 -d mysql:5.7 --lower_case_table_names=1
[root@template ~]# docker run --name mysql03 -p 3308:3306 -e MYSQL_ROOT_PASSWORD=123456 -d mysql:5.7 --lower_case_table_names=1

2、修改配置文件

将容器里面的配置文件复制出来，主要修改服务器的配置；在root目录下创建一个/server/backup的目录存放从Docker容器里面复制过来的配置文件。进入目录：cd /server/backup

因为在docker中vi命令都没有

# 创建备份目录
[root@template ~]# mkdir /server/backup -p

# 使用docker cp将文件传到宿主机
[root@template ~]# cd /server/backup/

# 进入容器查看mysql文件
[root@template backup]# docker exec -it  mysql01 bash
bash-4.2# mysql -uroot -p
Enter password:

# 从Docker容器里面复制过来的配置文件,配置文件路径不一样
[root@template ~]# docker cp mysql01:/etc/my.cnf  mysql01.cnf
[root@template ~]# docker cp mysql02:/etc/my.cnf  mysql02.cnf
Successfully copied 3.072kB to /root/mysql02.cnf
[root@template ~]# docker cp mysql03:/etc/my.cnf  mysql03.cnf
Successfully copied 3.072kB to /root/mysql03.cnf
[root@template ~]# ll
total 16
-rw-------. 1 root root 1425 Mar  3 18:52 anaconda-ks.cfg
-rw-r--r--. 1 root root 1159 Mar 22 04:51 mysql01.cnf
-rw-r--r--. 1 root root 1159 Mar 22 04:51 mysql02.cnf
-rw-r--r--. 1 root root 1159 Mar 22 04:51 mysql03.cnf

3、主库的mysql01.cnf

[root@template ~]# vim mysql01.cnf
[mysqld]
server_id=1
log_bin=mysql01.bin
# 添加server_id 和 开启日志

4、从库修改server_id即可

[root@template ~]# vim mysql02.cnf
server_id=2
[root@template ~]# vim mysql03.cnf
server_id=3

5、修改完成后，将 mysql01.cnf mysql02.cnf mysql03.cnf 三个文件传入容器中

[root@template ~]# docker cp mysql01.cnf mysql01:/etc/my.cnf
Successfully copied 3.072kB to mysql01:/etc/my.cnf
[root@template ~]# docker cp mysql02.cnf mysql02:/etc/my.cnf
Successfully copied 3.072kB to mysql02:/etc/my.cnf
[root@template ~]# docker cp mysql03.cnf mysql03:/etc/my.cnf
Successfully copied 3.072kB to mysql03:/etc/my.cnf

6、重启数据库

[root@template ~]# docker restart mysql01  mysql02 mysql03

7、测试连接

[root@node03 ~]# mysql -uroot -p123456 -h 192.168.11.10 -P 3306
mysql: [Warning] Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 2
Server version: 5.7.41-log MySQL Community Server (GPL)

Copyright (c) 2000, 2021, Oracle and/or its affiliates.

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> \q
Bye
[root@node03 ~]# mysql -uroot -p123456 -h 192.168.11.10 -P 3307
mysql: [Warning] Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 2
Server version: 5.7.41 MySQL Community Server (GPL)

Copyright (c) 2000, 2021, Oracle and/or its affiliates.

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> \q
Bye
[root@node03 ~]# mysql -uroot -p123456 -h 192.168.11.10 -P 3308
mysql: [Warning] Using a password on the command line interface can be insecure.
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 2
Server version: 5.7.41 MySQL Community Server (GPL)

Copyright (c) 2000, 2021, Oracle and/or its affiliates.

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>

8、在3306作为主库

[root@template backup]# docker exec -it mysql01 bash
bash-4.2# mysql -uroot -p123456

9、创建一个rep用户

mysql> create user 'rep'@'%' identified by '123456';
Query OK, 0 rows affected (0.02 sec)

10、添加权限

mysql> grant replication slave on *.* to 'rep'@'%';
Query OK, 0 rows affected (0.00 sec)

11、刷新权限表

mysql> flush privileges;
Query OK, 0 rows affected (0.00 sec)

12、测试用rep登录

bash-4.2# mysql -urep -p123456

13、进入从库做配置

# 查看主库上的信息，注意用户，要用root用户，开始用的rep错误信息如下：
mysql> show master status;
ERROR 1227 (42000): Access denied; you need (at least one of) the SUPER, REPLICATION CLIENT privilege(s) for this operation
# 查看主库上的信息
mysql> show master status;
+----------------+----------+--------------+------------------+-------------------+
| File           | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+----------------+----------+--------------+------------------+-------------------+
| mysql01.000001 |      745 |              |                  |                   |
+----------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)


[root@template ~]# docker exec -it mysql02 bash
[root@template ~]# docker exec -it mysql03 bash

bash-4.2# mysql -uroot -p123456
mysql> change master to
    -> master_host="192.168.11.10",
    -> master_user="rep",
    -> master_password="123456",
    -> master_log_file="mysql01.000001",
    -> master_log_pos=745;
Query OK, 0 rows affected, 2 warnings (0.01 sec)

14、开启slave并且查看俩个线程状态

mysql> start slave;
Query OK, 0 rows affected (0.01 sec)

mysql> show slave status \G
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: 192.168.11.10
                  Master_User: rep
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: mysql01.000001
          Read_Master_Log_Pos: 745
               Relay_Log_File: cb6044d1b02b-relay-bin.000002
                Relay_Log_Pos: 318
        Relay_Master_Log_File: mysql01.000001
             Slave_IO_Running: Yes
            Slave_SQL_Running: Yes

15、可以用客户端连接测试，实验完成！！！

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