mysql主從配置實現一主一從讀寫分離

主從介紹
Mysql主從又叫Replication、AB複製。簡單講就是A與B兩臺機器作主從後，在A上寫數據，另一臺B也會跟着寫數據，實現數據實時同步

mysql主從是基於binlog，主上需開啓binlog才能進行主從

主從過程大概有3個步驟

主將更改操做記錄到binlog裏

從將主的binlog事件（sql語句） 同步本機上並記錄在relaylog裏

從根據relaylog裏面的sql語句按順序執行

主從做用

• 實時災備，用於故障切換
• 讀寫分離，提供查詢服務
• 備份，避免影響業務

主從形式

* 一主一從
* 主主複製
* 一主多從---擴展系統讀取的性能，由於讀是在從庫讀取的
* 多主一從---5.7版本開始支持
* 聯級複製

主從複製原理

主從複製步驟

• 主庫將全部的寫操做記錄在binlog日誌中，並生成log dump線程，將binlog日誌傳給從庫的I/O線程

• 從庫生成兩個線程，一個是I/O線程，另外一個是SQL線程

• I/O線程去請求主庫的binlog日誌，並將binlog日誌中的文件寫入relay log（中繼日誌）中
• SQL線程會讀取relay loy中的內容，並解析成具體的操做，來實現主從的操做一致，達到最終數據一致的目的

主從複製配置步驟：

1. 確保從數據庫與主數據庫裏的數據一致
2. 在主數據庫裏建立一個同步帳戶受權給從數據庫使用
3. 配合主數據庫（修改配置文件）
4. 配置從數據庫（修改配置文件）

需求
搭建兩臺MYSQL服務器，一臺做爲主服務器，一臺做爲從服務器，主服務器進行寫操做，從服務器進行讀操做

環境說明

數據庫角色	IP	應用與系統	有無數據
主數據庫	192.168.55.130	centos7 mysql-5.7	有
從數據庫	192.168.55.129	centos7 mysql-5.7	無

在兩臺服務器上都按裝mysql

環境準備
關閉防火牆以SELINUX
[root@yanyinglai ~]# systemctl stop firewalld
[root@yanyinglai ~]# systemctl disable firewalld
[root@yanyinglai ~]#  sed -ri 's/(SELINUX=).*/\1disabled/g' /etc/selinux/config
[root@yanyinglai ~]# setenforce 0

安裝mysql
安裝依賴包
[root@yanyinglai ~]# yum -y install ncurses-devel openssl-devel openssl cmake mariadb-devel

建立用戶和組
[root@yanyinglai ~]# groupadd -r -g 306 mysql
[root@yanyinglai ~]# useradd -M -s /sbin/nologin -g 306 -u 306 mysql

下載二進制格式的mysql軟件包
[root@yanyinglai ~]# cd /usr/src/
[root@yanyinglai src]#wget https://downloads.mysql.com/archives/get/file/mysql-5.7.22-linux-glibc2.12-x86_64.tar.gz

解壓軟件至/usr/local/
[root@yanyinglai src]# ls
debug  kernels  mysql-5.7.22-linux-glibc2.12-x86_64.tar.gz
[root@yanyinglai src]# tar xf mysql-5.7.22-linux-glibc2.12-x86_64.tar.gz -C /usr/local/
[root@yanyinglai src]#  ls  /usr/local/
bin  etc  games  include  lib  lib64  libexec  mysql-5.7.22-linux-glibc2.12-x86_64  sbin  share  src
[root@yanyinglai src]#  cd  /usr/local/
[root@yanyinglai local]# ln -sv mysql-5.7.22-linux-glibc2.12-x86_64/ mysql
"mysql" -> "mysql-5.7.22-linux-glibc2.12-x86_64/"
[root@yanyinglai local]# ll

總用量 0
drwxr-xr-x. 2 root root   6 11月  5 2016 bin
drwxr-xr-x. 2 root root   6 11月  5 2016 etc
drwxr-xr-x. 2 root root   6 11月  5 2016 games
drwxr-xr-x. 2 root root   6 11月  5 2016 include
drwxr-xr-x. 2 root root   6 11月  5 2016 lib
drwxr-xr-x. 2 root root   6 11月  5 2016 lib64
drwxr-xr-x. 2 root root   6 11月  5 2016 libexec
lrwxrwxrwx. 1 root root  36 9月   7 22:20 mysql -> mysql-5.7.22-linux-glibc2.12-x86_64/
drwxr-xr-x. 9 root root 129 9月   7 22:19 mysql-5.7.22-linux-glibc2.12-x86_64
drwxr-xr-x. 2 root root   6 11月  5 2016 sbin
drwxr-xr-x. 5 root root  49 9月   3 23:02 share
drwxr-xr-x. 2 root root   6 11月  5 2016 src

修改目錄/usr/locaal/mysql的屬主屬組
[root@yanyinglai local]# chown -R mysql.mysql /usr/local/mysql
[root@yanyinglai local]#  ll /usr/local/mysql -d
lrwxrwxrwx. 1 mysql mysql 36 9月   7 22:20 /usr/local/mysql -> mysql-5.7.22-linux-glibc2.12-x86_64/

添加環境變量
[root@yanyinglai local]# ls /usr/local/mysql
bin  COPYING  docs  include  lib  man  README  share  support-files
[root@yanyinglai local]# cd
[root@yanyinglai ~]# echo 'export PATH=/usr/local/mysql/bin:$PATH' > /etc/profile.d/mysql.sh
[root@yanyinglai ~]# . /etc/profile.d/mysql.sh
[root@yanyinglai ~]# echo $PATH
/usr/local/mysql/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/root/bin

創建數據存放目錄
[root@yanyinglai ~]# cd /usr/local/mysql
[root@yanyinglai mysql]# mkdir /opt/data
[root@yanyinglai mysql]#  chown -R mysql.mysql /opt/data/
[root@yanyinglai mysql]#  ll /opt/
總用量 0
drwxr-xr-x. 2 mysql mysql 6 9月   7 22:25 data

初始化數據庫
[root@yanyinglai mysql]# /usr/local/mysql/bin/mysqld --initialize --user=mysql --datadir=/opt/data/
//這個命令的最後會生成一個臨時密碼，此處密碼是1EbNA-k*BtKo

配置mysql
[root@yanyinglai ~]# ln -sv /usr/local/mysql/include/ /usr/local/include/mysql
"/usr/local/include/mysql" -> "/usr/local/mysql/include/"
[root@yanyinglai ~]# echo '/usr/local/mysql/lib' > /etc/ld.so.conf.d/mysql.conf
[root@yanyinglai ~]#  ldconfig -v

生成配置文件
[root@yanyinglai ~]# cat > /etc/my.cnf <<EOF
> [mysqld]
> basedir = /usr/local/mysql
> datadir = /opt/data
> socket = /tmp/mysql.sock
> port = 3306
> pid-file = /opt/data/mysql.pid
> user = mysql
> skip-name-resolve
> EOF

配置服務啓動腳本
[root@yanyinglai ~]# cp -a /usr/local/mysql/support-files/mysql.server /etc/init.d/mysqld
[root@yanyinglai ~]#  sed -ri 's#^(basedir=).*#\1/usr/local/mysql#g' /etc/init.d/mysqld
[root@yanyinglai ~]# sed -ri 's#^(datadir=).*#\1/opt/data#g' /etc/init.d/mysqld

啓動mysql
[root@yanyinglai ~]#  service mysqld start
Starting MySQL.Logging to '/opt/data/yanyinglai.err'.
.. SUCCESS!
[root@yanyinglai ~]#  ps -ef|grep mysql
root       4897      1  0 22:38 pts/2    00:00:00 /bin/sh /usr/local/mysql/bin/mysqld_safe --datadir=/opt/data --pid-file=/opt/data/mysql.pid
mysql      5075   4897  6 22:38 pts/2    00:00:01 /usr/local/mysql/bin/mysqld --basedir=/usr/local/mysql --datadir=/opt/data --plugin-dir=/usr/local/mysql/lib/plugin --user=mysql --log-error=yanyinglai.err --pid-file=/opt/data/mysql.pid --socket=/tmp/mysql.sock --port=3306
root       5109   4668  0 22:38 pts/2    00:00:00 grep --color=auto mysql
[root@yanyinglai ~]# ss -antl
State       Recv-Q Send-Q                     Local Address:Port                                    Peer Address:Port              
LISTEN      0      128                                    *:22                                                 *:*                  
LISTEN      0      100                            127.0.0.1:25                                                 *:*                  
LISTEN      0      128                                   :::22                                                :::*                  
LISTEN      0      100                                  ::1:25                                                :::*                  
LISTEN      0      80                                    :::3306                                              :::*                  

修改密碼
使用臨時密碼修改
[root@yanyinglai ~]# mysql -uroot -p
Enter password:
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 2
Server version: 5.7.22

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> set password = password('123456');
Query OK, 0 rows affected, 1 warning (0.00 sec)

mysql> quit
Bye

mysql主從配置
確保從數據庫與主數據庫的數據同樣先在主數據庫建立所須要同步的庫和表
[root@yanyinglai ~]# mysql -uroot -p
Enter password:
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 4
Server version: 5.7.22 MySQL Community Server (GPL)

Copyright (c) 2000, 2018, Oracle and/or its affiliates. Al

Oracle is a registered trademark of Oracle Corporation and
affiliates. Other names may be trademarks of their respect
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the curr

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

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

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

mysql> use yan;
Database changed
mysql> create table tom (id int not null,name varchar(100)not null ,age tinyint);
Query OK, 0 rows affected (11.83 sec)

mysql> insert tom (id,name,age) values(1,'zhangshan',20),(2,'wangwu',7),(3,'lisi',23);
Query OK, 3 rows affected (0.07 sec)
Records: 3  Duplicates: 0  Warnings: 0

mysql> select * from tom;
+----+-----------+------+
| id | name      | age  |
+----+-----------+------+
|  1 | zhangshan |   20 |
|  2 | wangwu    |    7 |
|  3 | lisi      |   23 |
+----+-----------+------+
3 rows in set (0.00 sec)

備份主庫
備份主庫時須要另開一個終端，給數據庫上讀鎖，避免在備份期間有其餘人在寫入致使數據同步的不一致

[root@yanyinglai ~]# mysql -uroot -p
Enter password:
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 5
Server version: 5.7.22 MySQL Community Server (GPL)

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> flush tables with read lock;
Query OK, 0 rows affected (0.76 sec)
//此鎖表的終端必須在備份完成之後才能退出（退出鎖表失效）

備份主庫並將備份文件傳送到從庫
[root@yanyinglai ~]# mysqldump -uroot -p123456 --all-databases > /opt/all-20180907.sql
mysqldump: [Warning] Using a password on the command line interface can be insecure.
[root@yanyinglai ~]# ls /opt/
all-20180907.sql  data
[root@yanyinglai ~]# scp /opt/all-20180907.sql root@192.168.55.129:/opt/
The authenticity of host '192.168.55.129 (192.168.55.129)' can't be established.
ECDSA key fingerprint is SHA256:7mLj77SFk7sPkhjpMPfdK3nZ98hOuyP4OKzjXeijSJ0.
ECDSA key fingerprint is MD5:a0:1b:eb:7f:f0:b6:7b:73:97:91:4c:f3:b1:89:d8:ea.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '192.168.55.129' (ECDSA) to the list of known hosts.
root@192.168.55.129's password:
all-20180907.sql       100%  784KB 783.3KB/s   00:01    

解除主庫的鎖表狀態，直接退出交互式界面便可

mysql> quit
Bye

在從庫上恢復主庫的備份並查看是否與主庫的數據保持一致

[root@yanyinglai ~]# mysql -uroot -p123456 < /opt/all-20180907.sql
mysql: [Warning] Using a password on the command line interface can be insecure.
[root@yanyinglai ~]# mysql -uroot -p123456
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 4
Server version: 5.7.22 MySQL Community Server (GPL)

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> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| lisi               |
| mysql              |
| performance_schema |
| sys                |
| wangwu             |
| yan                |
+--------------------+
7 rows in set (0.18 sec)

mysql> use yan;
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> select * from tom;
+----+-----------+------+
| id | name      | age  |
+----+-----------+------+
|  1 | zhangshan |   20 |
|  2 | wangwu    |    7 |
|  3 | lisi      |   23 |
+----+-----------+------+
3 rows in set (0.06 sec)
在主數據庫建立一個同步帳戶受權給從數據使用
[root@yanyinglai ~]# mysql -uroot -p
Enter password:
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 7
Server version: 5.7.22 MySQL Community Server (GPL)

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> create user 'repl'@'192.168.55.129' identified by '123456';
Query OK, 0 rows affected (5.50 sec)

mysql> grant replication slave on *.* to 'repl'@'192.168.55.129';
Query OK, 0 rows affected (0.04 sec)

mysql> flush privileges;
Query OK, 0 rows affected (0.09 sec)

配置主數據庫編輯配置文件
[root@yanyinglai ~]# vim /etc/my.cnf
[root@yanyinglai ~]# cat /etc/my.cnf
[mysqld]
basedir = /usr/local/mysql
datadir = /opt/data
socket = /tmp/mysql.sock
port = 3306
pid-file = /opt/data/mysql.pid
user = mysql
skip-name-resolve
//添加如下內容
log-bin=mysql-bin //啓用binlog日誌
server-id=1 //主數據庫服務器惟一標識符 主的必須必從大
log-error=/opt/data/mysql.log

重啓mysql服務
[root@yanyinglai ~]# service mysqld restart
Shutting down MySQL..... SUCCESS!
Starting MySQL.Logging to '/opt/data/mysql.log'.
............................... SUCCESS!
[root@yanyinglai ~]# ss -antl
State       Recv-Q Send-Q Local Address:Port               Peer Address:Port              
LISTEN      0      128     *:22                  *:*                  
LISTEN      0      100    127.0.0.1:25                  *:*                  
LISTEN      0      128    :::22                 :::*                  
LISTEN      0      100       ::1:25                 :::*                  
LISTEN      0      80     :::3306               :::*

查看主庫的狀態
mysql> show master status;
+------------------+----------+--------------+------------------+-------------------+
| File             | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+-------------------+
| mysql-bin.000001 |      154 |              |                  |                   |
+------------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)
配置從數據庫
編輯配置文件
[root@yanyinglai ~]# cat /etc/my.cnf
[mysqld]
basedir = /usr/local/mysql
datadir = /opt/data
socket = /tmp/mysql.sock
port = 3306
pid-file = /opt/data/mysql.pid
user = mysql
skip-name-resolve
//添加如下內容：
server-id=2 //設置從庫的惟一標識符 從的必須比主小
relay-log=mysql-relay-bin //啓用中繼日誌relay log
error-log=/opt/data/mysql.log

重啓從庫的mysql服務

[root@yanyinglai ~]# service mysqld restart
Shutting down MySQL.. SUCCESS!
Starting MySQL.. SUCCESS!
[root@yanyinglai ~]# ss -antl
State       Recv-Q Send-Q Local Address:Port               Peer Address:Port              
LISTEN      0      128     *:22                  *:*                  
LISTEN      0      100    127.0.0.1:25                  *:*                  
LISTEN      0      128    :::22                 :::*                  
LISTEN      0      100       ::1:25                 :::*                  
LISTEN      0      80     :::3306               :::*                  

配置並啓動主從複製
mysql> change master to
    -> master_host='192.168.55.130',
    -> master_user='repl',
    -> master_password='123456',
    -> master_log_file='mysql-bin.000001',
    -> master_log_pos=154;
Query OK, 0 rows affected, 2 warnings (0.28 sec)

查看從服務器狀態

mysql> show slave status\G;
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: 192.168.55.130
                  Master_User: repl
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: mysql-bin.000001
          Read_Master_Log_Pos: 154
               Relay_Log_File: mysql-relay-bin.000003
                Relay_Log_Pos: 320
        Relay_Master_Log_File: mysql-bin.000001
             Slave_IO_Running: Yes                                     //此處必須是yes
            Slave_SQL_Running: Yes                                    //此處必須是yes       
              Replicate_Do_DB:
          Replicate_Ignore_DB:
           Replicate_Do_Table:
       Replicate_Ignore_Table:
      Replicate_Wild_Do_Table:
  Replicate_Wild_Ignore_Table:
                   Last_Errno: 0
                   Last_Error:
                 Skip_Counter: 0
          Exec_Master_Log_Pos: 154
              Relay_Log_Space: 527
              Until_Condition: None
               Until_Log_File:
                Until_Log_Pos: 0
           Master_SSL_Allowed: No
           Master_SSL_CA_File:
           Master_SSL_CA_Path:
              Master_SSL_Cert:
            Master_SSL_Cipher:
               Master_SSL_Key:
        Seconds_Behind_Master: 0
Master_SSL_Verify_Server_Cert: No
                Last_IO_Errno: 0
                Last_IO_Error:
               Last_SQL_Errno: 0
               Last_SQL_Error:
  Replicate_Ignore_Server_Ids:
             Master_Server_Id: 1
                  Master_UUID: 5abf1791-b2af-11e8-b6ad-000c2980fbb4
             Master_Info_File: /opt/data/master.info
                    SQL_Delay: 0
          SQL_Remaining_Delay: NULL
      Slave_SQL_Running_State: Slave has read all relay log; waiting for more updates
           Master_Retry_Count: 86400
                  Master_Bind:
      Last_IO_Error_Timestamp:
     Last_SQL_Error_Timestamp:
               Master_SSL_Crl:
           Master_SSL_Crlpath:
           Retrieved_Gtid_Set:
            Executed_Gtid_Set:
                Auto_Position: 0
         Replicate_Rewrite_DB:
                 Channel_Name:
           Master_TLS_Version:
1 row in set (0.00 sec)

ERROR:
No query specified
測試驗證在主服務器的yan庫的tom表插入數據:
mysql> use yan;
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> select * from tom;
+----+-----------+------+
| id | name      | age  |
+----+-----------+------+
|  1 | zhangshan |   20 |
|  2 | wangwu    |    7 |
|  3 | lisi      |   23 |
+----+-----------+------+
3 rows in set (0.09 sec)

mysql> insert tom(id,name,age) value (4,"yyl",18);
Query OK, 1 row affected (0.14 sec)

mysql> select * from tom;
+----+-----------+------+
| id | name      | age  |
+----+-----------+------+
|  1 | zhangshan |   20 |
|  2 | wangwu    |    7 |
|  3 | lisi      |   23 |
|  4 | yyl       |   18 |
+----+-----------+------+
4 rows in set (0.00 sec)
在從數據庫查看是否數據同步
mysql> use yan;
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> select * from tom;
+----+-----------+------+
| id | name      | age  |
+----+-----------+------+
|  1 | zhangshan |   20 |
|  2 | wangwu    |    7 |
|  3 | lisi      |   23 |
|  4 | yyl       |   18 |
+----+-----------+------+
4 rows in set (0.00 sec)