centos7安装mysql5.7

1. 检测并删除自带的mariadb
   rpm -qa|grep mariadb
   yum remove mariadb-*
2. 检测并卸载旧版mysql
   rpm -qa | grep -i mysql
   rpm -e --nodeps mysql*
   查找mysql文件并删除： find / -name mysql
   删除配置文档：rm -rf /etc/my.cnf
3. 解压并安装msyql
   解压：tar xvf mysql-5.7.26-1.el7.x86_64.rpm-bundle.tar
   安装（注意顺序不能错，有依赖关系）：

   rpm -ivh mysql-community-common-5.7.26-1.el7.x86_64.rpm 
   rpm -ivh mysql-community-libs-5.7.26-1.el7.x86_64.rpm 
   rpm -ivh mysql-community-client-5.7.26-1.el7.x86_64.rpm 
   rpm -ivh mysql-community-server-5.7.26-1.el7.x86_64.rpm 
   

   安装server报错解决：yum -y install numactl
   安装完成后msyql文件存储目录如下：
4. 配置mysql
   4.1 添加msyql用户
   groupadd mysql
   useradd -g mysql mysql
   4.2 初始化用户
   mysqld --initialize --user=mysql
   4.3 查看初始密码
   cat /var/log/mysqld.log |grep password
   启动mysql：systemctl start mysqld
   4.4 登录mysql并修改密码
   mysql -u root -p
   alter user ‘root’@‘localhost’ identified by ‘root1234’;
   4.5 开启远程登录
   use mysql;
   update user set host=’%’ where user = ‘root’;
   select user,host from user;
   4.6 赋予任何主机访问数据的权限
   GRANT ALL PRIVILEGES ON . TO ‘root’@’%’ WITH GRANT OPTION;
   FLUSH PRIVILEGES;
   4.7 设置开机启动，并查看
   systemctl enable mysqld
   systemctl list-unit-files|grep enabled
   4.8 防火墙开放3306端口，并重置
   firewall-cmd --zone=public --add-port=3306/tcp --permanent
   firewall-cmd --reload