centos7 安装mariadb
一、使用国内源：
mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-
Base.repo.backup
wget -O /etc/yum.repos.d/CentOS-Base.repo
http://mirrors.aliyun.com/repo/Centos-7.repo
二、安装mariadb
yum -y install mariadb mariadb-server mariadb-devel
三、cat /etc/my.cnf
[mysqld]default-storage-engine = innodb
innodb_file_per_table
collation-server = utf8_general_ci
init-connect = 'SET NAMES utf8'
character-set-server = utf8
四、启动mariadb
root用户直接启动，由于我的环境是vagrant ssh连接的，默认的是vagrant用户
systemctl start mariadb #用root用户启动，非root用户需要sudo
mysql进入mariadb：
Welcome to the MariaDB monitor. Commands end with ; or \g.
Your MariaDB connection id is 4
Server version: 5.5.56-MariaDB MariaDB Server
Copyright (c) 2000, 2017, 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 |
| test |
+--------------------+
2 rows in set (0.00 sec)
MariaDB [(none)]> select * from mysql.user \G
ERROR 1142 (42000): SELECT command denied to user ''@'localhost' for table 'user'
#这里就2个库，mysql库看不到，当然也查看不了
MariaDB [(none)]> select user();
+-------------------+
| user() |
+-------------------+
| vagrant@localhost |
+-------------------+
1 row in set (0.00 sec)
#看到 当前登录的用户是，因为刚才是mysql 直接进来的，此时我们要给mariadb配置初始密码；
mysqladmin -u root password #设置root密码。
再来，这次不直接mysql进来了
mysql -uroot -p
这里输入刚才的密码
进来了
MariaDB [(none)]> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| test |
+--------------------+
4 rows in set (0.00 sec)
MariaDB [(none)]> select * from mysql.user \G 正常查询
忘记root密码：
- systemctl stop mariadb 先关闭服务
- su - root 切到系统root用户
- mysqld_safe --skip-grant-tables & 跳过认证启动服务
- mysql mysql进入服务
- use mysql 切换到mysql库
- UPDATE user SET password=password('heheda') WHERE user='root';
- flush privileges;
- ps -ef |grep mysql|grep -v grep |awk '{print $2}'|xargs kill -9
- systemctl start mariadb