1、通过rpm包安装mysql5.7、expect、mysql server

通过MySQL官方的 Yum Repository 安装MySQL

安装 expect（下面的sh文件执行时依赖expect，需在server之前安装）

yum install -y http://dev.mysql.com/get/mysql57-community-release-el7-10.noarch.rpm
yum install -y http://mirror.centos.org/centos/7/os/x86_64/Packages/expect-5.45-14.el7_1.x86_64.rpm
yum install -y mysql-community-server 

若因网络问题安装失败可以尝试再次执行

例：

2、启动mysql服务并设置开机自启动

systemctl start mysqld.service
systemctl enable mysqld.service

3、设置自定义密码

创建一个sh文件，内容写入：(变量newpassword为要定义的密码，默认为root)

#!/bin/bash
password=$(grep 'temporary password' /var/log/mysqld.log | awk -F 'localhost: ' '{print $2;}')
newpassword=root # <--password
expect <<EOF
spawn mysql -uroot -p 
expect "password" 
send "${password}\n"
expect "mysql>" 
send "set global validate_password_policy=0;\n"
expect "mysql>" 
send "set global validate_password_length=1;\n"
expect "mysql>" 
send "ALTER USER 'root'@'localhost' IDENTIFIED BY \"${newpassword}\";\n"
expect "mysql>"
send "use mysql;\n"
expect "mysql>" 
send "update user set host='%' where user='root' and host='localhost';\n"
expect "mysql>"
send "flush privileges;\n"
expect eof
EOF

例：

注解：

　　获取MySQL默认的密码：grep 'temporary password' /var/log/mysqld.log | awk -F 'localhost: ' '{print $2;}'

　　关闭密码必须含有大小写字母数字和特殊字符的限制：validate_password_policy=0

　　关闭密码长度限制：validate_password_length=1

　　允许被外部访问：update user set host='%' where user='root' and host='localhost';