centos7安装mysql

1、先检测系统是否自带原有版本mysql安装包，如果有要先卸载删除，不然不能成功安装和启动；

rpm -qa|grep mysql  
yum remove mysql mysql-server mysql-libs compat-mysql51    注意这个代码，卸载不干净
rm -rf /etc/my.cnf

a)删除分散mysql文件夹

whereis mysql 

/usr/lib/mysql /var/lib64/mysql

清空相关mysql的所有目录以及文件
rm -rf /usr/lib/mysql
rm -rf /usr/share/mysql

rm -rf /usr/my.cnf

2、安装MySQL

wget https://dev.mysql.com/get/mysql57-community-release-el7-9.noarch.rpm

 

rpm -ivh mysql57-community-release-el7-9.noarch.rpm

 

yum install mysql-community-server

3、MySQL的启动配置

systemctl start mysqld #启动MySQL

systemctl stop mysqld #关闭MySQL

systemctl restart mysqld #重启MySQL

systemctl status mysqld #查看MySQL运行状态

systemctl enable mysqld #设置开机启动

systemctl disable mysqld #关闭开机启动

4. 防火墙设置

centos7 防火墙设置

第一种 firewall
永久的开放、关闭、查看端口
sudo firewall-cmd --zone=public --add-port=3000/tcp --permanent
sudo firewall-cmd --zone=public --remove-port=3000/tcp --permanent
sudo firewall-cmd --zone=public --query-port=3306/tcp
sudo firewall-cmd --reload

之后检查新的防火墙规则
firewall-cmd --list-all

//检查防火墙状态
firewall-cmd --state

systemctl enable firewalld
systemctl disable firewalld
systemctl start firewalld
systemctl stop firewalld
systemctl restart firewalld
systemctl status firewalld

第二种 iptables
CentOS7默认的防火墙不是iptables,而是firewalld
关闭firewall：
systemctl stop firewalld
systemctl disable firewalld #禁止firewall开机启动

#安装iptables-services
yum install iptables-services

vim /etc/sysconfig/iptables

service iptables restart
service iptables save

5. 数据库初始化

mysql5.7.6以后的版本在启动数据库的时候，会生成密码放到日志文件里，可从从日志获取：

[root@localhost local]# cat /var/log/mysqld.log | grep 'password'
2017-02-08T10:48:53.368640Z 1 [Note] A temporary password is generated for root@localhost: lRym!ofXx6/r
日志的第一条最后那串字符就是初始密码，这里是 lRym!ofXx6/r
使用该密码登录即可

[root@localhost local]# mysql -uroot -p
Enter password:
登录后输入sql语句发现

mysql> show databases;
ERROR 1820 (HY000): You must reset your password using ALTER USER statement before executing this statement.
意思是要修改初始密码，修改方法如下(这里密码是Xm123456@)：

mysql> set password='Xm123456@';
Query OK, 0 rows affected (0.00 sec)
mysql> quit
Bye
用新密码重新登录即可，测试可以执行sql语句了，到此修改初始root密码完成。

--设置外面客户端可登陆
show databases;
use mysql
select host,user from user;
update user set host='%' where user='root' and host='localhost';
flush privileges;
好了

--设置简单密码
set global validate_password_policy=0;
set global validate_password_length=4;

--权限设置
grant all privileges on *.* TO 'root'@'%' identified by 'root' with grant option;
flush privileges;

--创建用户
create user 'risk'@'%' identified by 'risk';
grant all privileges on *.* to 'risk'@'%' identified by 'risk';
flush privileges;