how to run and connect to multiple MySQL on the same machine.

以RPM方式安装MySQL

以下命令来自于icoding的老师：

1、下载rpm包
wget https://dev.mysql.com/get/Downloads/MySQL-5.7/mysql-5.7.28-1.el7.x86_64.rpm-bundle.tar# 如果提示需要账号密码，就用这个方式下载
# wget --http-user=youremail@email.com --http-passwd=yourpassword https://dev.mysql.com/get/Downloads/MySQL-5.7/mysql-5.7.28-1.el7.x86_64.rpm-bundle.tar2、查看系统是否自带mariadb
rpm -qa | grep mariadb3、将查出的mariadb进行卸载
rpm -e --nodeps mariadb-libs-5.5.64-1.el7.x86_644、把刚刚下载的mysql tar解压
tar -xvf mysql-5.7.28-1.el7.x86_64.rpm-bundle.tar5、在解压目录安装如下4个mysql核心包
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.rpm6、安装到server时缺少依赖报错
error: Failed dependencies:libaio.so.1()(64bit) is needed by mysql-community-server-5.7.28-1.el7.x86_64libaio.so.1(LIBAIO_0.1)(64bit) is needed by mysql-community-server-5.7.28-1.el7.x86_64libaio.so.1(LIBAIO_0.4)(64bit) is needed by mysql-community-server-5.7.28-1.el7.x86_647、安装缺少的依赖
yum -y install libaio8、再次安装server
rpm -ivh mysql-community-server-5.7.28-1.el7.x86_64.rpm9、启动mysql服务
service mysqld start10、查看v5.7版本的默认登录密码
grep password /var/log/mysqld.log11、登录到mysql命令行，修改默认密码
ALTER USER 'root'@'localhost' IDENTIFIED BY '123456';12、会告诉你密码不符合规范，可以修改校验等级和长度后再次执行上面的语句
set global validate_password_policy=LOW;
set global validate_password_length=6; 13、账户授权
use mysql;
select host,user from user;
# 所有ip都可以访问数据库
grant all privileges on *.* to [user name]@'%' identified by '123456';
# 只有内网网段ip才可访问，并授权账号可以授权其他人
# grant all privileges on *.* to [user name]@'192.168.%' identified by '123456' with grant option;
flush privileges;

配置多个instances

MySQL 官网 有一篇介绍 https://dev.mysql.com/doc/refman/5.7/en/using-systemd.html#systemd-multiple-mysql-instances，可以copy里面的配置文件过来，将里面的文件目录改成自己机器上的目录，并且确保mysql账户有读写权限（chown -R mysql:mysql [相应目录或者文件]）。为了方便连接进入mysql, 我在各个instance的最后都先加上了（skip-grant-tables）。

[mysqld@replica01]
server-id=212
datadir=/var/lib/mysql-replica01
socket=/var/lib/mysql-replica01/mysql.sock
port=3307
log-error=/var/log/mysqld-replica01.log
pid-file=/var/run/mysqld/mysqld212.pidslow_query_log=ON
slow_query_log_file=/usr/local/slowlog-replica01/slow.log
slow_launch_time=4
long_query_time=3
# chown -R mysql:mysql /usr/local/slowlog/log_bin=/usr/local/binlog/mysql-bin-replica01
binlog_format=ROW
# binlog日志切割的大小
max_binlog_size=500m
# binlog过期清理时间
expire_logs_days=3
skip-grant-tables[mysqld@replica02]
server-id=213
datadir=/var/lib/mysql-replica02
socket=/var/lib/mysql-replica02/mysql.sock
port=3308
log-error=/var/log/mysqld-replica02.log
pid-file=/var/run/mysqld/mysqld213.pidslow_query_log=ON
slow_query_log_file=/usr/local/slowlog-replica02/slow.log
slow_launch_time=4
long_query_time=3log_bin=/usr/local/binlog/mysql-bin-replica02
binlog_format=ROW
# binlog日志切割的大小
max_binlog_size=500m
# binlog过期清理时间
expire_logs_days=3skip-grant-tables

启动各个instance

service mysqld@replica01 restart
mysql -S /var/lib/mysql-replica01/mysql.sock

service mysqld@replica02 restart
mysql -S /var/lib/mysql-replica02/mysql.sock

连接进入之后，可以在修改密码：

mysql> update user set password=password("新密码") where user="root";
mysql> flush privileges;
mysql> quit注意：如果在执行该步骤的时候出现ERROR 1290 (HY000): The MySQL server is running with the --skip-grant-tables option so it cannot execute this statement 错误。则执行下 flush privileges 命令，再执行该命令即可。

root账户就已经重置成新的密码了。

最后编辑my.cnf,去掉一开始添加的内容（skip-grant-tables），然后重启MySQL即可。