一、清理環境

檢視是否已安裝
#rpm -qa |grep -i mysql
#rpm -qa |grep -i mariadb --（centos7預設系統自帶的檢視版本號並進行刪除）
#rpm -e mariadb-libs-5.5.56-2.el7.x86_64  --刪除mariadb

 # yum remove mariadb-libs-5.5.56-2.el7.x86_64 -- 刪除mariadb

# yum install perl perl-devel   //安裝依賴包,根據各系統環境而定

二、開始安裝
#--上傳mysql rpm安裝包到伺服器（安裝包可以去oracle官網下載）

# 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--下載安裝MySQL5.7社群版-----------------

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、啟動&開機自啟
# systemctl enable mysqld
# systemctl start mysqld
# systemctl status mysqld

四、獲取隨機root密碼
# grep password /var/log/mysqld.log //日誌檔案查詢臨時密碼

 # mysql -u root -p

Enter password:

五、修改密碼

修改當前登入使用者

ALTER USER USER() IDENTIFIED BY 'Abc123@#$';

六、使用者管理

建立新使用者

mysql> use mysql;

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

取消授權

revoke all on db1.t1 from 'admin'@"%";
revoke all on db1.* from 'admin'@"%";
revoke all privileges on *.* from 'admin'@'%';

3)設定使用者 root 可以在任意 IP 下被訪問
grant all privileges on *.* to root@"%" identified by "Abc123@#$";

七、my.cnf引數配置調整MySQL資料儲存目錄datadir、socket

# systemctl stop mysqld
# cp -rp /var/lib/mysql /data --複製資料檔案到新的目錄
# 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目錄

[mysqld]

port=3306
#datadir=/var/lib/mysql
datadir=/data/mysql #修改資料檔案目錄
#socket=/var/lib/mysql/mysql.sock
socket=/data/mysql/mysql.sock #修改socket目錄

------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)

調整目錄後，MySQL無法啟動了，目錄許可權處理過，還是啟動不了

方法一、

臨時關閉SELinux：

# setenforce 0

永久關閉SELinux：

 # vi /etc/sysconfig/selinux

然後將配置SELinux=enforcing改為SELinux=disabled

# sestatus ##檢視SELinux狀態

 # systemctl start mysqld    --關閉SELinux後MySQL可以正常啟動

######datadir、socket路徑修改後因為SELinux安全問題導致無法啟動，在網上找了幾天也沒有人有說清楚，說到需關閉SELinux就已經不錯了。

其實真正的問題就是datadir、socket、log修改後的新路徑資料夾許可權只有MySQL使用者和使用者組，沒有其他的使用者，所以受SELinux影響無法寫入導致啟動失敗。

方法二、

# ls -ldZ /data/mysql                                            ##檢視目錄的SElinux 標籤
# yum provides semanage                                  ###安裝
# yum -y install policycoreutils-python.x86_64    ###安裝
# semanage fcontext -a -t mysqld_db_t "/data/mysql(/.*)?"
# restorecon -Rv /data/mysql
# ls -ldZ /data/mysql                                            ##再檢視目錄的SElinux 標籤

# systemctl start mysqld                     ##處理後，MySQL啟動正常

八、防火牆埠開放
# firewall-cmd --zone=public --add-port=3306/tcp --permanent
# firewall-cmd --reload

九、通過客戶端遠端連線測試。OK完成