liunx虚拟机Centos彻底卸载MariaDB并重新安装mysql

因为CentOs7镜像文件自带mariadb，想自己安装mysql，所以需要卸载mariadb

卸载MariaDB

查询安装的mariadb软件

[root@Hadoop102 ~]# rpm -qa|grep mariadb
mariadb-5.5.56-2.el7.x86_64
mariadb-libs-5.5.56-2.el7.x86_64
mariadb-server-5.5.56-2.el7.x86_64

挨个卸载：

yum remove mariadb-libs-5.5.52-1.el7.x86_64

删除遗留的目录：

rm -rf /etc/my.cnf
rm -rf /var/lib/mysql

安装mysql

上传 mysql-5.7.30-1.el7.x86_64.rpm-bundle.tar mysql的yum文件包

解压：

 tar -xvf mysql-5.7.30-1.el7.x86_64.rpm-bundle.tar

rpm -ivh mysql-community-common-5.7.30-1.el7.x86_64.rpm

rpm -ivh mysql-community-libs-5.7.30-1.el7.x86_64.rpm

rpm -ivh mysql-community-client-5.7.30-1.el7.x86_64.rpm

rpm -ivh mysql-community-server-5.7.30-1.el7.x86_64.rpm 

如果遇到报错：

原因：这是由于yum安装了旧版本的GPG keys造成的
解决办法：后面加上 --force --nodeps
例如：
rpm -ivh mysql-community-libs-5.7.30-1.el7.x86_64.rpm --force --nodeps

---------------------- 安装完毕 ------------------

初始化mysql

mysqld --initialize

更改所属组

chown mysql:mysql /var/lib/mysql -R

启动mysql

systemctl start mysqld.service

查看mysql状态

systemctl status mysqld.service

成功：

查看MySQL 生成的临时root密码

 cat /var/log/mysqld.log
 #或者
 grep 'temporary password' /var/log/mysqld.log

修改mysql root密码、授权远程访问

# 登陆
mysql -uroot -p
Enter password : #这里输入在日志中生成的临时密码

#更新root密码 设置为 hadoop
ALTER USER 'root'@'localhost' IDENTIFIED BY 'hadoop';

#授权 远程访问
GRANT ALL PRIVILEGES ON *.* TO 'root'@'%' IDENTIFIED BY 'hadoop' WITH GRANT OPTION;

#mysql的启动与关闭 状态查看
systemctl stop mysqld
systemctl status mysqld
systemctl start mysqld

#建议设置开机自启动
systemctl enable mysqld

#查看是否已经设置自启动
systemctl list-unit-files | grep mysqld

可参考：
https://blog.csdn.net/sinat_35626559/article/details/84898673