centos7 yum安装mysql5.x及启动失败解决

Step1: 检测系统是否自带安装MySQL

#yum list installed | grep mysql

Step2: 删除系统自带的mysql及其依赖 命令：

# yum -y remove mysql-libs.x86_64

Step3: 给CentOS添加rpm源，而且选择较新的源 命令：

#wget dev.mysql.com/get/mysql-community-release-el6-5.noarch.rpm
#yum localinstall mysql-community-release-el6-5.noarch.rpm
# yum repolist all | grep mysql
# yum-config-manager --disable mysql55-community
# yum-config-manager --disable mysql56-community
# yum-config-manager --enable mysql57-community-dmr
# yum repolist enabled | grep mysql

Step4:安装mysql 服务器 命令：

# yum install mysql-community-server

Step5: 启动mysql 命令:

#service mysqld start

Step6: 查看mysql是否自启动,而且设置开启自启动 命令:

# chkconfig --list | grep mysqld
# chkconfig mysqld on

Step7: mysql安全设置 命令：

# mysql_secure_installation

centos yum 安装mysql5.7 以及 默认root密码查看

grep "password" /var/log/mysqld.log 
mysql
set global validate_password_policy=0;  
set global validate_password_length=4;  
set password for 'xxxx'@'localhost'=password('xxxx');
flush privileges;

mysql centos 远程登陆

GRANT ALL PRIVILEGES ON *.* TO 'root'@'%' IDENTIFIED BY 'xxx' WITH GRANT OPTION;

mysql centos 密码 忘记 root

vi /etc/my.cnf
在[mysqld]的段中加上一句：skip-grant-tables
例如：
[mysqld]
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
skip-grant-tables
保存而且退出vi。
service mysqld restart
update user set authentication_string=password('xxx') where user='root';
alter user 'root'@'localhost' identified by 'xxx';

启动失败 mysql 5.6.25启动不起来

[root@root ~]# /etc/init.d/mysqld start
Starting mysqld (via systemctl):  Job for mysqld.service failed because the control process exited with error code. See "systemctl status mysqld.service" and "journalctl -xe" for details.

mkdir -p /var/run/mysqld/
chown mysql.mysql /var/run/mysqld/