在Centos7中用MariaDB代替了mysql数据库。所以在新安装MySQL前必须做好对系统的清理工作。
一．清理CentOS7下的MariaDB。
[root@localhost ~]#rpm -qa | gremp mariadb
[root@localhost ~]# rpm -e --nodeps mariadb.x86_64 1:5.5.41-2.el7_0
二．下载MySQL的yum包
Linux系统自带的repo是不会自动更新每个软件的最新版本（基本都是比较靠后的稳定版），所以无法通过yum方式安装MySQL的高级版本。所以我们需要先安装带有当前可用的mysql5系列社区版资源的rpm包（确保电脑联网）。
[root@localhost ~]#wget http://dev.mysql.com/get/mysql-community-release-el7-5.noarch.rpm
[root@localhost ~]# rpm -ivh mysql-community-release-el7-5.noarch.rpm
查看当前可用的mysql安装资源
[root@localhost ~]# yum repolist enabled | grep "mysql.*-community.*"
mysql-connectors-community/x86_64 MySQL Connectors Community 21
mysql-tools-community/x86_64 MySQL Tools Community 33
mysql56-community/x86_64 MySQL 5.6 Community Server 214
安装mysql
[root@localhost ~]#yum install mysql-community-server
已加载插件：fastestmirror, langpacks
base | 3.6 kB 00:00
extras | 3.4 kB 00:00
mysql-connectors-community | 2.5 kB 00:00
mysql-tools-community | 2.5 kB 00:00
mysql56-community | 2.5 kB 00:00
updates | 3.4 kB 00:00
(1/5): extras/7/x86_64/primary_db | 117 kB 00:00
(2/5): mysql-connectors-community/x86_64/primary_db | 9.8 kB 00:00
(3/5): mysql-tools-community/x86_64/primary_db | 25 kB 00:01
(4/5): mysql56-community/x86_64/primary_db | 115 kB 00:01
(5/5): updates/7/x86_64/primary_db | 3.9 MB 00:01
Determining fastest mirrors
* base: mirrors.pubyun.com
* extras: mirrors.pubyun.com
* updates: mirrors.pubyun.com
正在解决依赖关系
--> 正在检查事务
---> 软件包 mysql-community-server.x86_64.0.5.6.29-2.el7 将被 安装
--> 正在处理依赖关系 mysql-community-common(x86-64) = 5.6.29-2.el7，它被软件包 mysql-community-server-5.6.29-2.el7.x86_64 需要
--> 正在处理依赖关系 mysql-community-client(x86-64) = 5.6.29-2.el7，它被软件包 mysql-community-server-5.6.29-2.el7.x86_64 需要
--> 正在检查事务
---> 软件包 mysql-community-client.x86_64.0.5.6.29-2.el7 将被 安装
--> 正在处理依赖关系 mysql-community-libs(x86-64) = 5.6.29-2.el7，它被软件包 mysql-community-client-5.6.29-2.el7.x86_64 需要
---> 软件包 mysql-community-common.x86_64.0.5.6.29-2.el7 将被 安装
--> 正在检查事务
---> 软件包 mysql-community-libs.x86_64.0.5.6.29-2.el7 将被 安装
--> 解决依赖关系完成
依赖关系解决
=================================================================
Package 架构 版本 源 大小
=================================================================
正在安装:
mysql-community-server x86_64 5.6.29-2.el7 mysql56-community 58 M
为依赖而安装:
mysql-community-client x86_64 5.6.29-2.el7 mysql56-community 19 M
mysql-community-common x86_64 5.6.29-2.el7 mysql56-community 256 k
mysql-community-libs x86_64 5.6.29-2.el7 mysql56-community 2.0 M
事务概要
=================================================================
安装 1 软件包 (+3 依赖软件包)
总下载量：79 M
安装大小：344 M
Is this ok [y/d/N]: y
Downloading packages:
警告：/var/cache/yum/x86_64/7/mysql56-community/packages/mysql-community-common-5.6.29-2.el7.x86_64.rpm: 头V3 DSA/SHA1 Signature, 密钥 ID 5072e1f5: NOKEY
mysql-community-common-5.6.29-2.el7.x86_64.rpm 的公钥尚未安装
(1/4): mysql-community-common-5.6.29-2.el7.x86_64.rpm | 256 kB 00:01
(2/4): mysql-community-libs-5.6.29-2.el7.x86_64.rpm | 2.0 MB 00:02
(3/4): mysql-community-server-5.6.29-2.el7.x86_64.rpm | 58 MB 00:29
mysql-community-client-5.6.29- FAILED
http://repo.mysql.com/yum/mysql-5.6-community/el/7/x86_64/mysql-community-client-5.6.29-2.el7.x86_64.rpm: [Errno 12] Timeout on http://repo.mysql.com/yum/mysql-5.6-community/el/7/x86_64/mysql-community-client-5.6.29-2.el7.x86_64.rpm: (28, 'Operation too slow. Less than 1000 bytes/sec transferred the last 30 seconds')
正在尝试其它镜像。
(4/4): mysql-community-client-5.6.29-2.el7.x86_64.rpm | 19 MB 12:12
-----------------------------------------------------------------
总计 105 kB/s | 79 MB 12:51
从 file:/etc/pki/rpm-gpg/RPM-GPG-KEY-mysql 检索密钥
导入 GPG key 0x5072E1F5:
用户ID : "MySQL Release Engineering <mysql-build@oss.oracle.com>"
指纹 : a4a9 4068 76fc bd3c 4567 70c8 8c71 8d3b 5072 e1f5
软件包 : mysql-community-release-el7-5.noarch (installed)
来自 : file:/etc/pki/rpm-gpg/RPM-GPG-KEY-mysql
是否继续？[y/N]：y
Running transaction check
Running transaction test
Transaction test succeeded
Running transaction
警告：RPM 数据库已被非 yum 程序修改。
正在安装 : mysql-community-common-5.6.29-2.el7.x86_64 1/4
正在安装 : mysql-community-libs-5.6.29-2.el7.x86_64 2/4
正在安装 : mysql-community-client-5.6.29-2.el7.x86_64 3/4
正在安装 : mysql-community-server-5.6.29-2.el7.x86_64 4/4
warning: /etc/my.cnf created as /etc/my.cnf.rpmnew
验证中 : mysql-community-common-5.6.29-2.el7.x86_64 1/4
验证中 : mysql-community-libs-5.6.29-2.el7.x86_64 2/4
验证中 : mysql-community-client-5.6.29-2.el7.x86_64 3/4
验证中 : mysql-community-server-5.6.29-2.el7.x86_64 4/4
已安装:
mysql-community-server.x86_64 0:5.6.29-2.el7
作为依赖被安装:
mysql-community-client.x86_64 0:5.6.29-2.el7
mysql-community-common.x86_64 0:5.6.29-2.el7
mysql-community-libs.x86_64 0:5.6.29-2.el7
完毕！
三．MySQL安装完成后，进行相关配置
a) #######安装成功后，将其加入开机启动
systemctl enable mysqldb)#######启动mysql服务进程
systemctl start mysqldc) #######配置mysql（设置密码等）
mysql_secure_installation
NOTE: RUNNING ALL PARTS OF THIS SCRIPT IS RECOMMENDED FOR ALL MySQL
SERVERS IN PRODUCTION USE! PLEASE READ EACH STEP CAREFULLY!
In order to log into MySQL to secure it, we'll need the current
password for the root user. If you've just installed MySQL, and
you haven't set the root password yet, the password will be blank,
so you should just press enter here.
Enter current password for root (enter for none):
OK, successfully used password, moving on...
Setting the root password ensures that nobody can log into the MySQL
root user without the proper authorisation.
Set root password? [Y/n] y [设置root用户密码]
New password:
Re-enter new password:
Password updated successfully!
Reloading privilege tables..
... Success!
By default, a MySQL installation has an anonymous user, allowing anyone
to log into MySQL without having to have a user account created for
them. This is intended only for testing, and to make the installation
go a bit smoother. You should remove them before moving into a
production environment.
Remove anonymous users? [Y/n] y [删除匿名用户]
... Success!
Normally, root should only be allowed to connect from 'localhost'. This
ensures that someone cannot guess at the root password from the network.
Disallow root login remotely? [Y/n] y [禁止root远程登录]
... Success!
By default, MySQL comes with a database named 'test' that anyone can
access. This is also intended only for testing, and should be removed
before moving into a production environment.
Remove test database and access to it? [Y/n] y [删除test数据库]
- Dropping test database...
ERROR 1008 (HY000) at line 1: Can't drop database 'test'; database doesn't exist
... Failed! Not critical, keep moving... - Removing privileges on test database... ... Success! Reloading the privilege tables will ensure that all changes made so farwill take effect immediately. Reload privilege tables now? [Y/n] y [刷新权限]... Success!
All done! If you've completed all of the above steps, your MySQL
installation should now be secure.
Thanks for using MySQL!
Cleaning up...
四．Yum安装后mysql的文件所在的位置：
/usr/bin(客户端程序和脚本)
/usr/sbin(mysql服务器)
/var/lib/mysql/(日志文件和数据库)
/usr/share/doc/packages(文档)
/usr/include/mysql(包含（头）文件)
/usr/lib/mysql(库文件)
/usr/share/mysql/(错误消息和字符集文件)
/usr/share/sql-bench(基准程序)
五．Yum安装的优缺点
优点：安装简单，适合初学者学习使用
缺点：需要单独下载客户端和服务器；安装路径不灵活，默认路径不能修改，一台服务器只能安装一个MySQL