CentOS 7安装MySQL5.7以及忘记root密码怎么办

一、通过Yum命令安装

1.下载rpm安装源

官方地址：https://dev.mysql.com/downloads/repo/yum/

rpm文件地址：https://dev.mysql.com/get/mysql57-community-release-el7-11.noarch.rpm

1）通过wget命令下载文件

[root@localhost yum.repos.d]# wget https://dev.mysql.com/get/mysql57-community-release-el7-11.noarch.rpm
--2018-08-05 06:14:15--  https://dev.mysql.com/get/mysql57-community-release-el7-11.noarch.rpm
Resolving dev.mysql.com (dev.mysql.com)... 137.254.60.11
Connecting to dev.mysql.com (dev.mysql.com)|137.254.60.11|:443... connected.
HTTP request sent, awaiting response... 302 Found
Location: https://repo.mysql.com//mysql57-community-release-el7-11.noarch.rpm [following]
--2018-08-05 06:14:17--  https://repo.mysql.com//mysql57-community-release-el7-11.noarch.rpm
Resolving repo.mysql.com (repo.mysql.com)... 104.95.206.140
Connecting to repo.mysql.com (repo.mysql.com)|104.95.206.140|:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: 25680 (25K) [application/x-redhat-package-manager]
Saving to: ‘mysql57-community-release-el7-11.noarch.rpm’

100%[==========================================================>] 25,680       152KB/s   in 0.2s   

2018-08-05 06:14:18 (152 KB/s) - ‘mysql57-community-release-el7-11.noarch.rpm’ saved [25680/25680]

2.安装Mysql

 1）安装Mysql源文件

yum localinstall -y mysql57-community-release-el7-11.noarch.rpm

[root@localhost yum.repos.d]# yum localinstall -y mysql57-community-release-el7-11.noarch.rpm 
Loaded plugins: fastestmirror, langpacks
Examining mysql57-community-release-el7-11.noarch.rpm: mysql57-community-release-el7-11.noarch
Marking mysql57-community-release-el7-11.noarch.rpm to be installed
Resolving Dependencies
--> Running transaction check
---> Package mysql57-community-release.noarch 0:el7-11 will be installed
--> Finished Dependency Resolution

Dependencies Resolved

====================================================================================================
 Package                      Arch      Version   Repository                                   Size
====================================================================================================
Installing:
 mysql57-community-release    noarch    el7-11    /mysql57-community-release-el7-11.noarch     31 k

Transaction Summary
====================================================================================================
Install  1 Package

Total size: 31 k
Installed size: 31 k
Downloading packages:
Running transaction check
Running transaction test
Transaction test succeeded
Running transaction
Warning: RPMDB altered outside of yum.
** Found 4 pre-existing rpmdb problem(s), 'yum check' output follows:
icedtea-web-1.7.1-1.el7.x86_64 has missing requires of java-1.8.0-openjdk
jline-1.0-8.el7.noarch has missing requires of java >= ('0', '1.5', None)
1:libreoffice-core-5.3.6.1-10.el7.x86_64 has missing requires of java-headless >= ('1', '1.6', None)
1:libreoffice-ure-5.3.6.1-10.el7.x86_64 has missing requires of libjvm.so()(64bit)
  Installing : mysql57-community-release-el7-11.noarch                                          1/1 
  Verifying  : mysql57-community-release-el7-11.noarch                                          1/1 

Installed:
  mysql57-community-release.noarch 0:el7-11                                                         

Complete!

2）查看Mysql源是否安装成功  

yum repolist enabled | grep "mysql.*-community.*"

[root@localhost yum.repos.d]# yum repolist enabled | grep "mysql.*-community.*"
mysql-connectors-community/x86_64 MySQL Connectors Community                 63
mysql-tools-community/x86_64      MySQL Tools Community                      69
mysql57-community/x86_64          MySQL 5.7 Community Server                287

 3）安装MySQL服务

 yum install -y mysql-server

这里与参考文章（mysql-community-server）不同，参考文章的没有包 ，一开始还以为是阿里云的库没有，把源配置恢复成系统默认的还是不行 在这边文章中修改了源配置，才发现是要安装mysql-server 

 4）查看MySQL服务是否安装成功

systemctl status mysqld

 

[root@localhost yum.repos.d]# systemctl status mysqld
● mysqld.service - MySQL Server
   Loaded: loaded (/usr/lib/systemd/system/mysqld.service; enabled; vendor preset: disabled)
   Active: inactive (dead)
     Docs: man:mysqld(8)
           http://dev.mysql.com/doc/refman/en/using-systemd.html

3.启动Mysql

systemctl start mysqld

4.修改root登录密码

 1）获取root默认密码（由于Mysql安全策略升级，安装完成后系统自动设置了一个随机密码）

grep 'temporary password' /var/log/mysqld.log

[root@localhost yum.repos.d]# grep 'temporary password' /var/log/mysqld.log
2018-08-05T10:57:20.546877Z 1 [Note] A temporary password is generated for root@localhost: :fqJ9?C!hhUu

 2）登录Mysql

mysql -u root -p

但是输入密码总是不对，不知道为什么

[root@localhost yum.repos.d]# mysql -u root -p
Enter password: 
ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: YES)

解决办法：（参考文章）

修改/etc/my.cnf   在末尾添加skip-grant-tables  设置关闭密码校验 validate_password = off

validate_password=off
skip-grant-tables

 3）修改密码

初始随机密码输入正确情况下：

  3.1）由于Mysql默认要求设置密码复杂度高（必须包含 大小写字母、数字、符号）

mysql> alter user 'root'@'localhost' identified by '123456';
ERROR 1819 (HY000): Your password does not satisfy the current policy requirements

这样设置是合法的：

mysql> alter user 'root'@'localhost' identified by 'Mysql666!';
Query OK, 0 rows affected (0.00 sec)

mysql> 

修改skip-grant-tables情况下：

use mysql;
ALTER USER 'root'@'localhost' IDENTIFIED BY 'new-password';
FLUSH PRIVILEGES;

注意：mysql5.7 user表里已经去掉了password字段

密码修改成功后，把 skip-grant-tables在配置文件my.cnf中删除,恢复正常，不然谁都可以登录数据库，修改密码啊什么的

 3.2）关闭Mysql密码校验规则，在前面my.cnf配置文件中设置validate_password = off

 

  3.2.2）重启Mysql服务生效

   systemctl restart mysqld

  4）设置简单密码 :

mysql> alter user 'root'@'localhost' identified by '123456';
Query OK, 0 rows affected (0.00 sec)

5.配置远程用户登录

grant all privileges on 数据库名.表名 to 用户名(root)@"%" identified by "密码"; # 数据库名.表名 如果写成*.*代表授权所有的数据库 

#如：
grant all privileges on *.* to root@"%" identified by "123456789";

 @ 后面是访问mysql的客户端IP地址（或是 主机名） % 代表任意的客户端，如果填写 localhost 为本地访问（那此用户就不能远程访问该mysql数据库了）。

同时也可以为现有的用户设置是否具有远程访问权限。

别忘记刷新权限 

flush privileges;

 1）指定Ip

mysql> grant all privileges on *.* to 'root'@'192.168.1.1' identified by '123456' with grant option;
Query OK, 0 rows affected, 1 warning (0.00 sec)

 2）root用户允许所有ip访问所有表

mysql> grant all privileges on *.* to 'root'@'%' identified by '123456' with grant option;
Query OK, 0 rows affected, 1 warning (0.00 sec)

6.设置开机启动

 systemctl enable mysqld

 systemctl daemon-reload

7.其他

 1）已配置远程访问权限，依然不能登录？请检查系统是否开启了防火墙。

  1.1）CentOS关闭防火墙 或者 开放3306端口

firewall-cmd --zone=public --add-port=3306/tcp --permanent

firewall-cmd --reload

   systemctl stop firewalld.service

  1.2）禁止防火墙开机启动

   systemctl disable firewalld.service

2）其他默认配置文件路径： 

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

 

参考文章 https://www.cnblogs.com/skychenjiajun/p/8244099.html