CentOS7安装MySQL5.6

这篇博客的主要内容是在CentOS7服务器上搭建一个MySQL5.6版本的数据库服务。

1、我的当前环境：

    [root@local-test ~]# cat /proc/cpuinfo |grep 'physical id'|wc -l
    2
    [root@local-test ~]# free -h
                          total        used        free      shared  buff/cache   available
    Mem:           2.8G        127M        2.4G        9.5M        191M        2.5G
    Swap:          2.0G          0B        2.0G
    [root@local-test ~]# uname -sr
    Linux 3.10.0-1062.el7.x86_64

2、创建mysql服务的相关目录和用户

a.创建安装目录：

    [root@local-test ~]# mkdir /opt/mysql

b.创建数据目录：

    [root@local-test ~]# mkdir /data/mysql/data -p

c.添加mysql用户

    [root@local-test ~]# useradd mysql -M -s /sbin/nologin        #-M:不创建家目录，-s /sbin/nologin :不允许该登录

3、下载MySQL安装包

下载MySQL-5.6.47版本:官网下载地址：https://dev.mysql.com/downloads/mysql/

    [root@local-test ~]# wget https://dev.mysql.com/get/Downloads/MySQL-5.6/mysql-5.6.47-linux-glibc2.12-x86_64.tar.gz

4、安装MySQL:

a.解压：

    [root@local-test ~]# tar xf mysql-5.6.47-linux-glibc2.12-x86_64.tar.gz -C /opt/mysql/

b.重命名目录：

    [root@local-test ~]# cd /opt/mysql/
    [root@local-test mysql]# mv mysql-5.6.47-linux-glibc2.12-x86_64/* .
    [root@local-test mysql]# rm -rf mysql-5.6.47-linux-glibc2.12-x86_64/
    [root@local-test mysql]# ls
    bin  data  docs  include  lib  LICENSE  man  mysql-test  README  scripts  share  sql-bench  support-files

c.安装mysql：把安装目录和数据目录授权给mysql用户

    [root@local-test mysql]# chown -R mysql.mysql /opt/mysql/ /data/mysql/data/
    [root@local-test mysql]# ./scripts/mysql_install_db --basedir=/opt/mysql/ --datadir=/data/mysql/data/ --user=mysql
    FATAL ERROR: please install the following Perl modules before executing ./scripts/mysql_install_db:
    Data::Dumper

出现这种问题很容易解决，仔细看错误信息可以知道，我们需要安装perl相关模块才能执行这个初始化脚本：

    [root@local-test mysql]# yum install perl-devel autoconf -y

安装完成之后再次执行初始化命令：

    [root@local-test mysql]# ./scripts/mysql_install_db --basedir=/opt/mysql/ --datadir=/data/mysql/data/ --user=mysql

返回信息如下：限于篇幅，此处不在粘贴，主要注意看是否出现两个OK

   ......

    OK

    ......

    OK
    
    ......
    此时说明你的mysql服务已经成功的安装到服务器上了，但是为了生产安全我们需要做一些基本的优化如下：

5、新安装MySQL基础优化：

a. my.cnf文件参数设置：

    [root@local-test mysql]# vim /etc/my.cnf
    [mysqld]
    #基础信息
    basedir=/opt/mysql
    datadir=/data/mysql/data
    socket=/var/lib/mysql/mysql.sock
    symbolic-links=0
    port=3306
    server_id=1
    #连接MySQL服务器时使用的字符编码设置
    init_connect='SET collation_connection = utf8mb4_unicode_ci'
    init_connect='SET NAMES utf8mb4'
    character-set-server=utf8mb4
    collation-server=utf8mb4_unicode_ci
    skip-character-set-client-handshake
    
    [client]
    #clinet的信息要与[mysqld]中的信息保持一致，特别注意socket的位置
    port = 3306
    socket = /var/lib/mysql/mysql.sock
    default_character_set=utf8mb4
    
    [mysqld_safe]
    log-error=/var/log/mysql/mysql.log
    pid-file=/var/lib/mysql/mysql.pid
    
    [mysql]
    default_character_set=utf8mb4

b. 启动脚本优化：

二进制包安装的mysql的启动脚本默认是在/opt/mysql/support-files目录下的mysql.server文件，我一般会把它放到/etc/init.d/下使用chkconfig管理，CentOS7一样适用。

    [root@local-test support-files]# cp  /opt/mysql/support-files/mysql.server /etc/init.d/mysqld
    [root@local-test support-files]# chkconfig --add mysqld
    [root@local-test support-files]# chkconfig --list |grep mysqld
    
    mysqld              0:off   1:off           2:on        3:on        4:on    5:on        6:off

c.启动MySQL服务

    [root@local-test support-files]# /etc/init.d/mysqld start
    Starting MySQL.Logging to '/var/log/mysql/mysql.log'.
    200228 03:45:07 mysqld_safe Directory '/var/lib/mysql' for UNIX socket file don't exists.
     ERROR! The server quit without updating PID file (/data/mysql/data/local-test.pid).

这个错误提示我们没有/var/log/mysql这个目录，所以需要新建一个，注意别忘了授权！

    [root@local-test support-files]# mkdir /var/lib/mysql
    [root@local-test support-files]# chown -R mysql.mysql /var/lib/mysql/

再次启动

    [root@local-test support-files]# /etc/init.d/mysqld start    
    Starting MySQL.Logging to '/var/log/mysql/mysql.log'.
    .... SUCCESS!
    [root@local-test support-files]#

d.登陆mysql

    [root@local-test support-files]# mysql
    -bash: mysql: command not found                    #/opt/mysql不在path搜索路径里
    [root@local-test support-files]# ln -s /opt/mysql/bin/* /usr/bin/
    [root@local-test support-files]# mysql
    Welcome to the MySQL monitor.  Commands end with ; or \g.
    Your MySQL connection id is 2
    Server version: 5.6.47 MySQL Community Server (GPL)

    Copyright (c) 2000, 2020, 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>

e.设置mysql管理员初始密码：

    [root@local-test support-files]# mysqladmin -uroot password '设置密码'

再次登陆就要使用密码了！

    [root@local-test support-files]# mysql -uroot -p