CentOS服务器安装mysql

1、配置YUM源

下载mysql源安装包

[root@localhost~]#wget http://dev.mysql.com/get/mysql57-community-release-el7-8.noarch.rpm

安装mysql源

[root@localhost~]# yum localinstall mysql57-community-release-el7-8.noarch.rpm

提示【Is this ok [y/d/N]: y 输入y回车】

检查MySQL源是否安装成功

[root@localhost ~]# yum repolist enabled | grep “mysql.-community.”

2、安装MySQL

[root@localhost ~]# yum install mysql-community-server

注意：安装过程中提示【Is this ok [y/d/N]: y 输入y回车】 

出现以下表示安装成功：

Replaced:
  mariadb-libs.x86_64 1:5.5.56-2.el7                                                                                                          

Complete!

3、启动MySQL服务

[root@localhost ~]# systemctl start mysqld

查看MySQL的启动状态

[root@localhost ~]# systemctl status mysqld

4.开机启动

[root@localhost ~]# systemctl enable mysqld
[root@localhost ~]# systemctl daemon-reload

查看mysql下root账号的默认密码 

mysql5.7安装完成之后，在/var/log/mysqld.log文件中给root生成了一个默认密码。通过下面的方式找到root默认密码，然后登录mysql。 

命令：

grep ‘temporary password’ /var/log/mysqld.log

[root@localhost /]# grep 'temporary password' /var/log/mysqld.log
2017-10-17T08:07:03.797098Z 1 [Note] A temporary password is generated for root@localhost: 3prjY9ktM,eL
[root@localhost /]#

默认的密码是：3prjY9ktM,eL

修改配置文件 

6.1. 默认配置文件路径 

配置文件：/etc/my.cnf 

日志文件：/var/log//var/log/mysqld.log 

服务启动脚本：/usr/lib/systemd/system/mysqld.service 

socket文件：/var/run/mysqld/mysqld.pid 

6.2. 修改my.cnf文件 

6.2.1. 修改密码策略 

mysql的密码策略分为三种： 

0或LOW：Length 

1或MEDIUM：Length; numeric, lowercase/uppercase, and special characters 

2或STRONG：Length; numeric, lowercase/uppercase, and special characters; dictionary file

在my.cnf文件中增加如下设置

如果不需要密码策略，禁用密码策略
validate_password = off

密码选择策略 0-LOW，1-MEDIUM，2-STRONG需要提供密码字典文件
validate_password_policy = 0

6.2.2. 修改字符编码为utf8 

在[mysqld]下增加如下配置

character_set_server = utf8 
init_connect = ‘SET NAMES utf8’

例：

[root@localhost /]# cd /etc/
[root@localhost etc]# vi my.cnf
validate_password = off# For advice on how to change settings please see
# http://dev.mysql.com/doc/refman/5.7/en/server-configuration-defaults.html
[mysqld]
#
# Remove leading # and set to the amount of RAM for the most important data
# cache in MySQL. Start at 70% of total RAM for dedicated server, else 10%.
# innodb_buffer_pool_size = 128M
#
# Remove leading # to turn on a very important data integrity option: logging
# changes to the binary log between backups.
# log_bin
#
# Remove leading # to set options mainly useful for reporting servers.
# The server defaults are faster for transactions and fast SELECTs.
# Adjust sizes as needed, experiment to find the optimal values.
# join_buffer_size = 128M
# sort_buffer_size = 2M
# read_rnd_buffer_size = 2M
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock

# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0

log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid
validate_password = off  #设置禁用密码策略

character_set_server = utf8  #修改字符编码为utf8
init_connect = 'SET NAMES utf8'
 ```
6.2.3. 保存my.cnf并重启mysql服务是配置生效 
命令：

systemctl restart mysqld

登录mysql`

命令：

mysql -uroot -p

输入密码：默认为刚才查到的密码”3prjY9ktM,eL”

``

[root@localhost etc]# mysql -uroot -p

Enter password:

Welcome to the MySQL monitor. Commands end with ; or \g.

Your MySQL connection id is 4

Server version: 5.7.20

Copyright (c) 2000, 2017, 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>

修改密码

命令：ALTER USER 'root'@'localhost' IDENTIFIED BY '12345678'; 
或命令：set password for 'root'@'localhost'=password('12345678');

说明：

1. 如果之前没有设置密码策略，则密码12345678则不会通过验证，密码修改会失败

 grant all privileges on *.* to 'root'@'0.0.0.0'identified by '123456' with grant option;

密码修改不成功时则部分功能也无法使用，例如查看密码策略

 show variables like ‘%password%’;

查看密码策略 

命令：show variables like '%password%'; 

此处为 validate_password = off 设置后的结果

查看字符编码 

命令：show variables like '%character%';

添加远程账户 

命令：

grant all privileges on *.* to 'root'@'%'identified by '123456' with grant option;

命令：FLUSH PRIVILEGES; 使设置生效

如果你想允许用户myuser从ip为0.0.0.0所有的主机连接到mysql服务器，并使用mypassword作为密码

刷新权限

FLUSH PRIVILEGES;

至此，可以远程连接并操作数据库啦！