mysql主从配置实现一主一从读写分离

时间：2022-06-01 19:34:40

主从介绍
Mysql主从又叫Replication、AB复制。简单讲就是A与B两台机器做主从后，在A上写数据，另外一台B也会跟着写数据，实现数据实时同步

mysql主从是基于binlog，主上需开启binlog才能进行主从

主从过程大概有3个步骤

主将更改操作记录到binlog里

从将主的binlog事件（sql语句） 同步本机上并记录在relaylog里

从根据relaylog里面的sql语句按顺序执行

主从作用

  • 实时灾备，用于故障切换
  • 读写分离，提供查询服务
  • 备份，避免影响业务

主从形式
mysql主从配置实现一主一从读写分离

* 一主一从 * 主主复制 * 一主多从---扩展系统读取的性能，因为读是在从库读取的 * 多主一从---5.7版本开始支持 * 联级复制

主从复制原理
mysql主从配置实现一主一从读写分离

主从复制步骤

  • 主库将所有的写操作记录在binlog日志中，并生成log dump线程，将binlog日志传给从库的I/O线程

  • 从库生成两个线程，一个是I/O线程，另一个是SQL线程

  • I/O线程去请求主库的binlog日志，并将binlog日志中的文件写入relay log（中继日志）中
  • SQL线程会读取relay loy中的内容，并解析成具体的操作，来实现主从的操作一致，达到最终数据一致的目的

主从复制配置步骤：

  1. 确保从数据库与主数据库里的数据一致
  2. 在主数据库里创建一个同步账户授权给从数据库使用
  3. 配合主数据库（修改配置文件）
  4. 配置从数据库（修改配置文件）

需求
搭建两台MYSQL服务器，一台作为主服务器，一台作为从服务器，主服务器进行写操作，从服务器进行读操作

环境说明

数据库角色 IP 应用与系统 有无数据
主数据库 192.168.55.130 centos7 mysql-5.7 有
从数据库 192.168.55.129 centos7 mysql-5.7 无

在两台服务器上都按装mysql

环境准备
关闭防火墙以SELINUX
[[email protected] ~]# systemctl stop firewalld [[email protected] ~]# systemctl disable firewalld [[email protected] ~]# sed -ri ‘s/(SELINUX=).*/1disabled/g‘ /etc/selinux/config [[email protected] ~]# setenforce 0 安装mysql 安装依赖包 [[email protected] ~]# yum -y install ncurses-devel openssl-devel openssl cmake mariadb-devel 创建用户和组 [[email protected] ~]# groupadd -r -g 306 mysql [[email protected] ~]# useradd -M -s /sbin/nologin -g 306 -u 306 mysql 下载二进制格式的mysql软件包 [[email protected] ~]# cd /usr/src/ [[email protected] src]#wget https://downloads.mysql.com/archives/get/file/mysql-5.7.22-linux-glibc2.12-x86_64.tar.gz 解压软件至/usr/local/ [[email protected] src]# ls debug kernels mysql-5.7.22-linux-glibc2.12-x86_64.tar.gz [[email protected] src]# tar xf mysql-5.7.22-linux-glibc2.12-x86_64.tar.gz -C /usr/local/ [[email protected] src]# ls /usr/local/ bin etc games include lib lib64 libexec mysql-5.7.22-linux-glibc2.12-x86_64 sbin share src [[email protected] src]# cd /usr/local/ [[email protected] local]# ln -sv mysql-5.7.22-linux-glibc2.12-x86_64/ mysql "mysql" -> "mysql-5.7.22-linux-glibc2.12-x86_64/" [[email protected] local]# ll 总用量 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 修改目录/usr/locaal/mysql的属主属组 [[email protected] local]# chown -R mysql.mysql /usr/local/mysql [[email protected] 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/ 添加环境变量 [[email protected] local]# ls /usr/local/mysql bin COPYING docs include lib man README share support-files [[email protected] local]# cd [[email protected] ~]# echo ‘export PATH=/usr/local/mysql/bin:$PATH‘ > /etc/profile.d/mysql.sh [[email protected] ~]# . /etc/profile.d/mysql.sh [[email protected] ~]# echo $PATH /usr/local/mysql/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/root/bin 建立数据存放目录 [[email protected] ~]# cd /usr/local/mysql [[email protected] mysql]# mkdir /opt/data [[email protected] mysql]# chown -R mysql.mysql /opt/data/ [[email protected] mysql]# ll /opt/ 总用量 0 drwxr-xr-x. 2 mysql mysql 6 9月 7 22:25 data 初始化数据库 [[email protected] mysql]# /usr/local/mysql/bin/mysqld --initialize --user=mysql --datadir=/opt/data/ //这个命令的最后会生成一个临时密码，此处密码是1EbNA-k*BtKo 配置mysql [[email protected] ~]# ln -sv /usr/local/mysql/include/ /usr/local/include/mysql "/usr/local/include/mysql" -> "/usr/local/mysql/include/" [[email protected] ~]# echo ‘/usr/local/mysql/lib‘ > /etc/ld.so.conf.d/mysql.conf [[email protected] ~]# ldconfig -v 生成配置文件 [[email protected] ~]# 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 配置服务启动脚本 [[email protected] ~]# cp -a /usr/local/mysql/support-files/mysql.server /etc/init.d/mysqld [[email protected] ~]# sed -ri ‘s#^(basedir=).*#1/usr/local/mysql#g‘ /etc/init.d/mysqld [[email protected] ~]# sed -ri ‘s#^(datadir=).*#1/opt/data#g‘ /etc/init.d/mysqld 启动mysql [[email protected] ~]# service mysqld start Starting MySQL.Logging to ‘/opt/data/yanyinglai.err‘. .. SUCCESS! [[email protected] ~]# 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 [[email protected] ~]# 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 :::* 修改密码 使用临时密码修改 [[email protected] ~]# 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主从配置 确保从数据库与主数据库的数据一样先在主数据库创建所需要同步的库和表 [[email protected] ~]# 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 (

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