[root@localhost home]# cat /etc/RedHat-release
CentOS Linux release 7.2.1511 (Core)
二、mysql安装安装mysql和mysql-devel都成功，但是安装mysql-server失败，如下：
[root@localhost home]# yum install mysql-server 已加载插件：fastestmirror, langpacks Repodata is over 2 weeks old. Install yum-cron? Or run: yum makecache fast base | 3.6 kB 00:00:00 extras | 3.4 kB 00:00:00 updates | 3.4 kB 00:00:00 (1/4): base/7/x86_64/group_gz | 155 kB 00:00:01 (2/4): extras/7/x86_64/primary_db | 139 kB 00:00:01 (3/4): base/7/x86_64/primary_db | 5.6 MB 00:00:38 (4/4): updates/7/x86_64/primary_db | 4.7 MB 00:00:39 Loading mirror speeds from cached hostfile * base: mirrors.163.com * extras: mirrors.163.com * updates: mirrors.163.com 没有可用软件包 mysql-server。 错误：无须任何处理
出现这样问题是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：
1、方法一：安装mariadb
MariaDB数据库管理系统是MySQL的一个分支，采用GPL授权许可 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。MariaDB由MySQL的创始人Michael Widenius（英语：Michael Widenius）主导开发，他早前将自己创建的公司MySQL AB卖给了SUN，此后，随着SUN被甲骨文收购，MySQL的所有权也落入Oracle的手中。MariaDB名称来自Michael Widenius的女儿Maria的名字。
安装mariadb，输入安装命令
[root@localhost home]# yum install mariadb-server mariadb
mariadb数据库的相关命令是：
systemctl start mariadb #启动MariaDB
systemctl stop mariadb #停止MariaDB
systemctl restart mariadb #重启MariaDB
systemctl enable mariadb #设置开机启动
先启动数据库
[root@yl-web yl]# systemctl start mariadb
默认无密码
[root@localhost lzh]# mysql -u root -p Enter password: Welcome to the MariaDB monitor. Commands end with ; or \g. Your MariaDB connection id is 6 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)]> show databases; +--------------------+ | Database | +--------------------+ | information_schema | | mysql | | performance_schema | | test | +--------------------+ 4 rows in set (0.01 sec) 2、方法二：官网下载安装mysql-server
# wget # rpm -ivh mysql-community-release-el7-5.noarch.rpm # yum install mysql-community-server
安装成功后重启mysql服务
# service mysqld restart
初次安装mysql，root账户没有密码
[root@localhost lzh]# mysql -u root Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 3 Server version: 5.6.26 MySQL Community Server (GPL) Copyright (c) 2000, 2015, 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> show databases; +--------------------+ | Database | +--------------------+ | information_schema | | mysql | | performance_schema | | test | +--------------------+ 4 rows in set (0.01 sec)
设置密码
mysql> set password for 'root'@'localhost' =password('password'); Query OK, 0 rows affected (0.00 sec)
安装完以后mariadb自动就被替换了，将不再生效。
[root@localhost lzh]# rpm -qa |grep mariadb