yum升级教程，阿里云香港服务器：Could not resolve host: mirrors.cloud.aliyuncs.com - kelvin_yin的专栏 - CSDN博客
内容
/etc/yum.repos.d目录全部移动到tmp文件夹，自己新建
```js
yum clean all
yum --disableplugin=fastestmirror makecache
yum --disableplugin=fastestmirror update
rpm -ivh --replacepkgs --replacefiles centos-release-7-6.1810.2.el7.centos.x86_64.rpm
rpm -Uvh https://mirror.webtatic.com/yum/el7/epel-release.rpm
rpm -Uvh https://mirror.webtatic.com/yum/el7/webtatic-release.rpm
```
/etc/yum.repos.d目录全部移动到tmp文件夹，自己新建
```js
yum clean all
yum --disableplugin=fastestmirror makecache
yum --disableplugin=fastestmirror update
rpm -ivh --replacepkgs --replacefiles centos-release-7-6.1810.2.el7.centos.x86_64.rpm
rpm -Uvh https://mirror.webtatic.com/yum/el7/epel-release.rpm
rpm -Uvh https://mirror.webtatic.com/yum/el7/webtatic-release.rpm
```