centos7安装MySQL

一，系统环境

[root@centos7 ~]# yum search libaio
CentOS Linux release 7.1.1503 (Core) #查看版本

二，安装

[root@centos7 ~]# yum install mysql
........
Installed:
mariadb.x86_64 1:5.5.52-1.el7
Dependency Installed:
mariadb-libs.x86_64 1:5.5.52-1.el7
Complete!
........
[root@centos7 ~]# yum install mysql-server
........
Installed:
mariadb-devel.x86_64 1:5.5.52-1.el7
Complete!
........#yum安装，过程省略

安装的MySQL和的mysql-devel的都成功，但是安装的MySQL服务器失败，如下所示

[root@centos7 ~]# yum install mysql-server
Loaded plugins: fastestmirror
Repository epel is listed more than once in the configuration
Loading mirror speeds from cached hostfile
No package mysql-server available.
Error: Nothing to do
#加载插件：fastestmirror
存储库epel在配置中被多次列出
从缓存的主机文件加载镜像速度
没有包mysql服务器可用。
错误：

查资料发现是CentOS 7版本将MySQL数据库软件从默认的程序列表中移除，用mariadb代替了。

有两种解决办法：

方法1：安装MariaDB的

MariaDB的数据库管理系统是MySQL的的一个分支，主要由开源社区在维护，采用GPL授权许可开发这个分支的原因之一是：甲骨文公司收购了MySQL的后，有将MySQL的闭源的潜在风险，因此社区采用分支的方式来避开这个风险。MariaDB 的目的是完全兼容MySQL，包括API和命令行，使之能轻松成为MySQL的代替品。

安装mariadb，大小59 M.

[root@centos7 ~]# yum install mariadb-server mariadb
.........
Installed:
mariadb-server.x86_64 1:5.5.52-1.el7
Dependency Installed:
perl-Compress-Raw-Bzip2.x86_64 0:2.061-3.el7 perl-Compress-Raw-Zlib.x86_64 1:2.061-4.el7
perl-DBD-MySQL.x86_64 0:4.023-5.el7 perl-DBI.x86_64 0:1.627-4.el7
perl-IO-Compress.noarch 0:2.061-2.el7 perl-Net-Daemon.noarch 0:0.48-5.el7
perl-PlRPC.noarch 0:0.2020-14.el7
Complete!
.........

安装过程省略，安装完成后设置MariaDB

[root@centos7 ~]# systemctl start mariadb #启动MariaDB
[root@centos7 ~]# systemctl enable mariadb #设置开机启动
Created symlink from /etc/systemd/system/multi-user.target.wants/mariadb.service to /usr/lib/systemd/system/mariadb.service.
[root@centos7 ~]# systemctl status mariadb #查看MariaDB状态
● mariadb.service - MariaDB database server
Loaded: loaded (/usr/lib/systemd/system/mariadb.service; enabled; vendor preset: disabled)
Active: active (running) since Mon 2017-09-24 17:23:09 CST; 33s ago
Main PID: 6676 (mysqld_safe)
CGroup: /system.slice/mariadb.service
├─6676 /bin/sh /usr/bin/mysqld_safe --basedir=/usr
└─6834 /usr/libexec/mysqld --basedir=/usr --datadir=/var/lib/mysql --plugin-dir=/usr/lib64/mysql/p...
Sep 24 17:23:07 iz8vbjca1ezyfhdmm3uxovz mariadb-prepare-db-dir[6598]: strongly recommended for production s...s.
Sep 24 17:23:07 iz8vbjca1ezyfhdmm3uxovz mariadb-prepare-db-dir[6598]: See the MariaDB Knowledgebase at http...he
Sep 24 17:23:07 iz8vbjca1ezyfhdmm3uxovz mariadb-prepare-db-dir[6598]: MySQL manual for more instructions.
Sep 24 17:23:07 iz8vbjca1ezyfhdmm3uxovz mariadb-prepare-db-dir[6598]: You can start the MariaDB daemon with:
Sep 24 17:23:07 iz8vbjca1ezyfhdmm3uxovz mariadb-prepare-db-dir[6598]: cd '/usr' ; /usr/bin/mysqld_safe --da...l'
Sep 24 17:23:07 iz8vbjca1ezyfhdmm3uxovz mariadb-prepare-db-dir[6598]: You can test the MariaDB daemon with ...pl
Sep 24 17:23:07 iz8vbjca1ezyfhdmm3uxovz mariadb-prepare-db-dir[6598]: cd '/usr/mysql-test' ; perl mysql-tes...pl
Sep 24 17:23:07 iz8vbjca1ezyfhdmm3uxovz mysqld_safe[6676]: 170924
17:23:07 mysqld_safe Logging to '/var/lo...g'.
Sep 24 17:23:07 iz8vbjca1ezyfhdmm3uxovz mysqld_safe[6676]: 170924
17:23:07 mysqld_safe Starting mysqld dae...sql
Sep 24 17:23:09 iz8vbjca1ezyfhdmm3uxovz systemd[1]: Started MariaDB database server.
Hint: Some lines were ellipsized, use -l to show in full.

启动MySQL

[root@centos7 ~]# mysql
Welcome to the MariaDB monitor. Commands end with ; or \g.
Your MariaDB connection id is 2
Server version: 5.5.52-MariaDB MariaDB Server
Copyright (c) 2000, 2016, Oracle, MariaDB Corporation Ab and others.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
MariaDB [(none)]>

安装mariadb后显示的也是 MariaDB [（无）]> ，可能看起来有点不习惯。下面是第二种方法。

---

方式2：从官网下载安装Mysql的

安装环境：CentOS 7 64位MINI版，安装MySQL

· 配置YUM源

在MySQL的官网中下载YUM源RPM安装包：HTTP：//dev.mysql.com/downloads/repo/yum/

# 下载mysql源安装包
shell> wget http://dev.mysql.com/get/mysql57-community-release-el7-8.noarch.rpm# 安装mysql源
shell> yum localinstall mysql57-community-release-el7-8.noarch.rpm

检查MySQL的源是否安装成功

# 下载mysql源安装包
shell> wget http://dev.mysql.com/get/mysql57-community-release-el7-8.noarch.rpm# 安装mysql源
shell> yum localinstall mysql57-community-release-el7-8.noarch.rpm

检查MySQL的源安装是否正确
看到上图所示表示安装成功。
可以修改vim /etc/yum.repos.d/mysql-community.repo源，改变默认安装的MySQL的版本。比如要安装5.6版本，将5.7源的启用= 1改成使能= 0。然后再将5.6源的使能= 0改成启用= 1即可改完之后的效果如下所示：

· 安装的MySQL

shell> yum install mysql-community-server

· 启动MySQL的服务

shell> systemctl start mysqld

· 开机启动

shell> systemctl enable mysqld
shell> systemctl daemon-reload

· 修改根本地登录密码

MySQL的安装完成之后，在/var/log/mysqld.log文件中给根生成了一个默认密码通过下面的方式找到根默认密码，然后登录MySQL的进行修改：

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

shell> mysql -uroot -p
mysql> ALTER USER 'root'@'localhost' IDENTIFIED BY 'MyNewPass4!';

或者

mysql> set password for 'root'@'localhost'=password('MyNewPass4!');

注意：mysql5.7默认安装了密码安全检查插件（validate_password），默认密码检查策略要求密码必须包含：大小写字母，数字和特殊符号，并且长度不能少于8位。否则会提示错误1819（HY000）：您的密码不符合当前的政策要求错误，如下图所示：密码策略提示
通过msyql环境变量可以查看密码策略的相关信息：

mysql> show variables like '%password%';

MySQL的密码策略
validate_password_policy：密码策略，默认为MEDIUM策略
validate_password_dictionary_file：密码策略文件，策略为强才需要
validate_password_length：密码最少长度
validate_password_mixed_case_count：大小写字符长度，至少1个
validate_password_number_count：数字至少1个
validate_password_special_char_count：特殊字符至少1个上述参数是默认策略中等的密码检查规则。

上述参数是默认策略中等的密码检查规则。

MySQL的官网密码策略详细说明：HTTP：//dev.mysql.com/doc/refman/5.7/en/validate-password-options-variables.html#sysvar_validate_password_policy

修改密码策略

在/etc/my.cnf中文件添加validate_password_policy配置，指定密码策略

# 选择0（LOW），1（MEDIUM），2（STRONG）其中一种，选择2需要提供密码字典文件
validate_password_policy=0

如果不需要密码策略，添加的my.cnf文件中添加如下配置禁用即可：

validate_password = off

---

三，卸载

· 检查是否安装了MySQL的

[root@centos7 ~]# yum list installed | grep mysql
mysql-community-client.x86_64 5.7.19-1.el7 @mysql57-community
mysql-community-common.x86_64 5.7.19-1.el7 @mysql57-community
mysql-community-libs.x86_64 5.7.19-1.el7 @mysql57-community
mysql-community-libs-compat.x86_64 5.7.19-1.el7 @mysql57-community
mysql-community-server.x86_64 5.7.19-1.el7 @mysql57-community
mysql57-community-release.noarch el7-11 @/mysql57-community-release-el7-11.noarch

· 卸载

[root@centos7 ~]# yum remove mysql-community-client mysql-community-common mysql-community-libs mysql-community-server mysql57-community-release
..........
Running transaction
Erasing : mysql57-community-release-el7-11.noarch 1/5
Erasing : mysql-community-server-5.7.19-1.el7.x86_64 2/5
Erasing : mysql-community-client-5.7.19-1.el7.x86_64 3/5
Erasing : mysql-community-libs-5.7.19-1.el7.x86_64 4/5
Erasing : mysql-community-common-5.7.19-1.el7.x86_64 5/5
Verifying : mysql-community-libs-5.7.19-1.el7.x86_64 1/5
Verifying : mysql-community-common-5.7.19-1.el7.x86_64 2/5
Verifying : mysql-community-client-5.7.19-1.el7.x86_64 3/5
Verifying : mysql57-community-release-el7-11.noarch 4/5
Verifying : mysql-community-server-5.7.19-1.el7.x86_64 5/5
Removed:
mysql-community-client.x86_64 0:5.7.19-1.el7 mysql-community-common.x86_64 0:5.7.19-1.el7
mysql-community-libs.x86_64 0:5.7.19-1.el7 mysql-community-server.x86_64 0:5.7.19-1.el7
mysql57-community-release.noarch 0:el7-11
...........
[root@centos7 ~]# rpm -qa |grep -i mysql
[root@centos7 ~]# find / -name mysql
/usr/share/mysql
/var/lib/mysql
/var/lib/mysql/mysql
[root@centos7 ~]# rm -rf /usr/share/mysql /var/lib/mysql /var/lib/mysql/mysql