CentOS7 安装MySQL5.7企业版（商业版）及修改my.cnf默认datadir、socket路径后无法启动的处理方法[亲测有效]

一、清理环境

查看是否已安装
#rpm -qa |grep -i mysql
#rpm -qa |grep -i mariadb –（centos7默认系统自带的查看版本号并进行删除）
#rpm -e mariadb-libs-5.5.56-2.el7.x86_64  –删除mariadb

 # yum remove mariadb-libs-5.5.56-2.el7.x86_64 — 删除mariadb

# yum install perl perl-devel   //安装依赖包,根据各系统环境而定

二、开始安装
#–上传mysql rpm安装包到服务器（安装包可以去oracle官网下载）

# rpm -ivh mysql-commercial-common-5.7.28-1.1.el7.x86_64.rpm
# rpm -ivh mysql-commercial-libs-5.7.28-1.1.el7.x86_64.rpm
# rpm -ivh mysql-commercial-libs-compat-5.7.28-1.1.el7.x86_64.rpm
# rpm -ivh mysql-commercial-client-5.7.28-1.1.el7.x86_64.rpm
# rpm -ivh mysql-commercial-server-5.7.28-1.1.el7.x86_64.rpm

—–or–下载安装MySQL5.7社区版—————–

wget https://dev.mysql.com/get/Downloads/MySQL-5.7/mysql-community-common-5.7.28-1.el7.x86_64.rpm
wget https://dev.mysql.com/get/Downloads/MySQL-5.7/mysql-community-libs-5.7.28-1.el7.x86_64.rpm
wget https://dev.mysql.com/get/Downloads/MySQL-5.7/mysql-community-client-5.7.28-1.el7.x86_64.rpm
wget https://dev.mysql.com/get/Downloads/MySQL-5.7/mysql-community-server-5.7.28-1.el7.x86_64.rpm

rpm -ivh mysql-community-common-5.7.28-1.el7.x86_64.rpm
rpm -ivh mysql-community-libs-5.7.28-1.el7.x86_64.rpm
rpm -ivh mysql-community-client-5.7.28-1.el7.x86_64.rpm
rpm -ivh mysql-community-server-5.7.28-1.el7.x86_64.rpm

—————————————————————

三、启动&开机自启
# systemctl enable mysqld
# systemctl start mysqld
# systemctl status mysqld

四、获取随机root密码
# grep password /var/log/mysqld.log //日志文件查找临时密码

 # mysql -u root -p

Enter password:

五、修改密码

修改当前登录用户

ALTER USER USER() IDENTIFIED BY “Abc123@#$”;

六、用户管理

创建新用户

mysql> use mysql;

mysql> create user “admin”@”%” identified by “Abc123@#$”;
Query OK, 0 rows affected (0.00 sec)
授权
grant select ,insert,update on db1.t1 to “admin”@”%” identified by “Abc123@#$”;
grant all privileges on db1.* to “admin”@”%” identified by “Abc123@#$”;
grant all privileges on *.* to “admin”@”%” identified by “Abc123@#$”;

取消授权

revoke all on db1.t1 from “admin”@”%”;
revoke all on db1.* from “admin”@”%”;
revoke all privileges on *.* from “admin”@”%”;

3)设置用户 root 可以在任意 IP 下被访问
grant all privileges on *.* to root@”%” identified by “Abc123@#$”;

七、my.cnf参数配置调整MySQL数据存储目录datadir、socket

# systemctl stop mysqld
# cp -rp /var/lib/mysql /data –复制数据文件到新的目录
# chown -R mysql:mysql /data/mysql 
# vi /etc/my.cnf

—–my.cnf修改——

[client]
port=3306
#socket=/var/lib/mysql/mysql.sock
socket=/data/mysql/mysql.sock  #修改socket目录

[mysqld]

port=3306
#datadir=/var/lib/mysql
datadir=/data/mysql #修改数据文件目录
#socket=/var/lib/mysql/mysql.sock
socket=/data/mysql/mysql.sock #修改socket目录

——end——

[root@Centos7 tools]# systemctl start mysqld

Job for mysqld.service failed because the control process exited with error code. See “systemctl status mysqld.service” and “journalctl -xe” for details.

[root@Centos7 tools]# /usr/bin/mysql start
ERROR 2002 (HY000): Can”t connect to local MySQL server through socket “/data/mysql/mysql.sock” (2)

调整目录后，MySQL无法启动了，目录权限处理过，还是启动不了

方法一、

临时关闭SELinux：

# setenforce 0

永久关闭SELinux：

 # vi /etc/sysconfig/selinux

然后将配置SELinux=enforcing改为SELinux=disabled

# sestatus ##查看SELinux状态

 # systemctl start mysqld    –关闭SELinux后MySQL可以正常启动

######datadir、socket路径修改后因为SELinux安全问题导致无法启动，在网上找了几天也没有人有说清楚，说到需关闭SELinux就已经不错了。

其实真正的问题就是datadir、socket、log修改后的新路径文件夹权限只有MySQL用户和用户组，没有其他的用户，所以受SELinux影响无法写入导致启动失败。

方法二、

# ls -ldZ /data/mysql                                            ##查看目录的SElinux 标签
# yum provides semanage                                  ###安装
# yum -y install policycoreutils-python.x86_64    ###安装

# chcon -Rv -u system_u -t mysqld_db_t /data/mysql
# semanage fcontext -a -t mysqld_db_t “/data/mysql(/.*)?”
# restorecon -Rv /data/mysql
# ls -ldZ /data/mysql                                            ##再查看目录的SElinux 标签

# systemctl start mysqld                     ##处理后，MySQL启动正常

八、防火墙端口开放
# firewall-cmd –zone=public –add-port=3306/tcp –permanent
# firewall-cmd –reload

九、通过客户端远程连接测试。OK完成