构建MySQL服务器的完整步骤

• 安装MySQL-server、MySQl-client软件包
• 修改数据库用户root的密码
• 确认MySQL服务程序运行、root可控
本课程将使用64位的RHEL 7操作系统，MySQL数据库的版本是5.7.17。
访问http://dev.mysql.com/downloads/mysql/，找到MySQL Community Server下载页面，平台选择“Red Hat Enterprise Linux 7/ Oracle Linux”，然后选择64位的bundle整合包下载
注意：下载MySQL软件时需要以Oracle网站账户登录，如果没有请根据页面提示先注册一个（免费）
步骤一：准备工作
1）停止mariadb服务

1.	[root@localhost ~]# systemctl  stop mariadb

2）删除/etc/my.cnf配置文件
此配置文件由RHEL自带的mariadb-libs库提供：

[root@localhost ~]# rm -rf /etc/my.cnf

3）删除数据

1.	 [root@localhost ~]# rm -rf /var/lib/mysql/*

4）卸载软件包（没有会显示未安装软件包）

1.	 [root@localhost ~]# rpm -e --nodeps mariadb-server mariadb2.	警告：/var/log/mariadb/mariadb.log 已另存为/var/log/mariadb/mariadb.log.rpmsave

步骤二：安装软件包
1）安装mysql时可能会缺少某些依赖包，需提前单独安装

1.	 [root@localhost ~]# yum -y install perl-Data-Dumper  perl-JSON  perl-Time-HiRes

2）物理机传输解压包给虚拟机192.168.4.1

1.	[root@room9pc01 ~]# cd 桌面2.	[root@room9pc01 桌面]# scp mysql-5.7.17.tar 192.168.4.1:/root/  //给虚拟机传包3.	root@192.168.4.1\'s password:4.	mysql-5.7.17.tar     100%  543MB  95.6MB/s   00:05

3）虚拟机192.168.4.1解压mysql-5.7.17.tar 整合包

1.	[root@localhost ~]# tar -xvf mysql-5.7.17.tar               //解压mysql整合包2.	./mysql-community-client-5.7.17-1.el7.x86_64.rpm3.	./mysql-community-common-5.7.17-1.el7.x86_64.rpm4.	./mysql-community-devel-5.7.17-1.el7.x86_64.rpm5.	./mysql-community-embedded-5.7.17-1.el7.x86_64.rpm6.	./mysql-community-embedded-compat-5.7.17-1.el7.x86_64.rpm7.	./mysql-community-embedded-devel-5.7.17-1.el7.x86_64.rpm8.	./mysql-community-libs-5.7.17-1.el7.x86_64.rpm9.	./mysql-community-libs-compat-5.7.17-1.el7.x86_64.rpm10.	./mysql-community-minimal-debuginfo-5.7.17-1.el7.x86_64.rpm11.	./mysql-community-server-5.7.17-1.el7.x86_64.rpm12.	./mysql-community-test-5.7.17-1.el7.x86_64.rpm

步骤三：启动MySQL数据库服务并设置开机自启

1.	[root@localhost ~]# systemctl start mysqld                  //启动mysql服务2.	[root@localhost ~]# systemctl enable mysqld                 //设置开机自启3.	[root@localhost ~]# systemctl status mysqld                 //查看mysql服务状态4.	● mysqld.service - MySQL Server5.	   Loaded: loaded (/usr/lib/systemd/system/mysqld.service; enabled; vendor preset: disabled)6.	   Active: active (running) since 二 2018-08-28 10:03:24 CST; 8min ago7.	     Docs: man:mysqld(8)8.	           http://dev.mysql.com/doc/refman/en/using-systemd.html9.	 Main PID: 4284 (mysqld)10.	   CGroup: /system.slice/mysqld.service11.	           └─4284 /usr/sbin/mysqld --daemonize --pid-file=/var/r...12.13.	8月 28 10:02:56 localhost.localdomain systemd[1]: Starting MySQ...14.	8月 28 10:03:24 localhost.localdomain systemd[1]: Started MySQL...15.	Hint: Some lines were ellipsized, use -l to show in full.

步骤四：连接MySQL服务器，修改密码
查看随机生成的root管理密码

1.	[root@localhost ~]#grep \'temporary password\' /var/log/mysqld.log2.	2017-04-01T18:10:42.948679Z 1 [Note] A temporary password is generated for root@localhost: mtoa>Av<p6Yk        //随机生成的管理密码为mtoa>Av<p6Yk

2）使用客户端命令mysql连接到MySQL服务器
提示验证时，填入前一步获得的随机密码，验证成功后即可进入“mysql> ”环境：

1.	[root@localhost ~]# mysql -u root -p\'mtoa>Av<p6Yk\'2.	mysql: [Warning] Using a password on the command line interface can be insecure.3.	Welcome to the MySQL monitor.  Commands end with ; or \\g.4.	Your MySQL connection id is 115.	Server version: 5.7.176.7.	Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.8.9.	Oracle is a registered trademark of Oracle Corporation and/or its10.	affiliates. Other names may be trademarks of their respective11.	owners.12.13.	Type \'help;\' or \'\\h\' for help. Type \'\\c\' to clear the current input statement.14.	mysql>                                     //登录成功后，进入SQL操作环境

用该密码登录到服务端后，必须马上修改密码，不然会报如下错误：

1.	mysql> show databases;2.	ERROR 1820 (HY000): You must reset your password using ALTER USER statement before executing this statement.

3）执行SET PASSWORD命令修改密码
这个其实与validate_password_policy的值有关，默认为1，所以刚开始设置的密码必须符合长度，且必须含有数字，小写或大写字母，特殊字符。如果我们不希望密码设置的那么复杂，需要修改两个全局参数：validate_password_policy与validate_password_length。validate_password_length默认值为8,最小值为4，如果你显性指定validate_password_length的值小于4，尽管不会报错，但validate_password_length的值将设为4。
可参考下列指令：

1.	mysql>set global validate_password_policy=0;      //只验证长度2.	Query OK, 0 rows affected (0.00 sec)3.	mysql>set global validate_password_length=6；     //修改密码长度,默认值是8个字符4.	Query OK, 0 rows affected (0.00 sec)5.	mysql> alter user user() identified by \"123456\";  //修改登陆密码6.	Query OK, 0 rows affected (0.00 sec)

上述操作的结果是——更改数据库用户root从本机访问时的密码，设为123456。
退出“mysql> ”环境，重新登录验证，必须采用新的密码才能登入：

1.	mysql> exit                                  //退出 mysql> 环境2.	Bye3.	[root@localhost ~]# mysql -u root -p        //重新登录4.	Enter password:                              //输入新设置的密码5.	Welcome to the MySQL monitor.  Commands end with ; or \\g.6.	Your MySQL connection id is 157.	Server version: 5.7.17 MySQL Community Server (GPL)8.9.	Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.10.11.	Oracle is a registered trademark of Oracle Corporation and/or its12.	affiliates. Other names may be trademarks of their respective13.	owners.14.15.	Type \'help;\' or \'\\h\' for help. Type \'\\c\' to clear the current input statement.