CentOS 7下MysqL下替换成MariaDB了，MariaDB数据库管理系统是MysqL的一个分支，主要由开源社区在维护，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。

快速安装

yum install -y mariadb-server

常用命令

yum install mariadb mariadb-server
systemctl start mariadb   #启动mariadb
systemctl enable mariadb  #设置开机自启动
systemctl stop mariadb    #停止MariaDB
systemctl restart mariadb #重启MariaDB

MySQL安全启动配置向导

mysql_secure_installation

执行后配置MYSQL相关信息

[root@localhost ~]# 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):  //初次运行直接回车
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] //是否设置root用户密码，输入Y并回车或直接回车

New password:  //设置root用户的密码

Re-enter new password://再次输入你设置的密码
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] //是否删除匿名用户,生产环境建议删除，所以直接回车
… 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] //是否禁止root远程登录,根据自己的需求选择Y/n并回车,建议禁止
… 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] //是否删除test数据库,直接回车
- Dropping test database…
… Success!
- Removing privileges on test database…
… Success!

Reloading the privilege tables will ensure that all changes made so far
will take effect immediately.
Reload privilege tables now? [Y/n] //是否重新加载权限表，直接回车
… Success!
Cleaning up…
All done! If you've completed all of the above steps, your MySQL
installation should now be secure.
Thanks for using MySQL!

连接mariaDB报错：is not allowed to connect to this MariaDB server

mysql -u root -p
use mysql;
update user set host = '%'  where user ='root';
flush privileges;
quit;

ERROR 1062 (23000): Duplicate entry ‘%-root’ for key ‘PRIMARY’

数据库的host信息已经存在%这个值，直接在mysql运行flush privileges; 命令即可。