如何在CentOS8上安装Mysql5.7

在CentOS8上，默认情况下直接使用yum安装mysql，安装的是Mysql 8.0，在一些比较老的项目中，我们需要使用的mysql版本是5.7，下面我分享一个在CentOS8中安装Myslq5.7的方法。

···
Dependencies resolved.
================================================================================
 Package       Arch    Version                                 Repository  Size
================================================================================
Installing:
 mysql         x86_64  8.0.17-3.module_el8.0.0+181+899d6349    AppStream   11 M
Installing dependencies:
 mysql-common  x86_64  8.0.17-3.module_el8.0.0+181+899d6349    AppStream  143 k
Enabling module streams:
 mysql                 8.0

Transaction Summary
================================================================================
Install  2 Packages
···

下载Mysql5.7的RPM包

进入https://downloads.mysql.com/archives/community/，选择对应的mysql版本和操作系统版本，下载以下包：

• RPM Package, MySQL Server
• RPM Package, Client Utilities
• RPM Package, Shared Libraries
• RPM Package, MySQL Configuration
  安装Mysql Server需要这些包。

安装过程

安装时需要按以下顺序安装，因为这些包存在依赖关系：
MySQL Configuration -> Shared Libraries -> Client Utilities -> MySQL Server

yum localinstall mysql-community-common-5.7.30-1.el7.x86_64.rpm
yum localinstall mysql-community-libs-5.7.30-1.el7.x86_64.rpm
yum localinstall mysql-community-client-5.7.30-1.el7.x86_64.rpm
yum localinstall mysql-community-server-5.7.30-1.el7.x86_64.rpm

配置Mysql

• 系统启动时自启动：

  systemctl enable mysqld

• 启动mysql服务：

  systemctl start mysqld

• 查看mysqld服务运行状态：

  systemctl status mysqld

输出内容：

● mysqld.service - MySQL Server
   Loaded: loaded (/usr/lib/systemd/system/mysqld.service; enabled; vendor preset: disabled)
   Active: active (running) since Fri 2020-08-21 02:07:18 EDT; 41min ago
     Docs: man:mysqld(8)
           http://dev.mysql.com/doc/refman/en/using-systemd.html
  Process: 55384 ExecStart=/usr/sbin/mysqld --daemonize --pid-file=/var/run/mysqld/mysqld.pid $MYSQLD_OPTS (code=exited, status=0/SUCCESS)
  Process: 55366 ExecStartPre=/usr/bin/mysqld_pre_systemd (code=exited, status=0/SUCCESS)
 Main PID: 55386 (mysqld)
    Tasks: 28 (limit: 24984)
   Memory: 178.1M
   CGroup: /system.slice/mysqld.service
           └─55386 /usr/sbin/mysqld --daemonize --pid-file=/var/run/mysqld/mysqld.pid

如果忘记root密码需要重置root密码可参考《如何重置Mysql5.7 root密码》。