yum -y update：升级所有包同时也升级软件和系统内核；
yum -y upgrade：只升级所有包，不升级软件和系统内核。
vmware安装centos7
https://blog.csdn.net/babyxue/article/details/80970526
https://www.cnblogs.com/double-K/p/10952233.html
安装jdk1.8 https://blog.csdn.net/qq_36522306/article/details/94599687
nginx https://www.jianshu.com/p/040473444236
redis安装 https://blog.csdn.net/qq_32092723/article/details/81162142
安装两个redis
https://blog.csdn.net/weixin_42555019/article/details/93066379
https://blog.csdn.net/qq_37495786/article/details/82683311
redis密码 https://blog.csdn.net/qq_42815754/article/details/83827375
mysql5.7安装 https://www.cnblogs.com/black-fact/p/10840332.html
安装指定的mysql版本 https://blog.csdn.net/qq_32596527/article/details/82797451