or download this
yum install libxml2 libxml2-devel
Could not retrieve mirrorlist http://mirrorlist.centos.org/?release=7S
+erver&arch=x86_64&repo=os&infra=$infra error was
14: curl#6 - "Could not resolve host: mirrorlist.centos.org; Unknown e
+rror"
...
yum-config-manager --save --setopt=<repoid>.skip_if_unavai
+lable=true
Cannot find a valid baseurl for repo: base/7Server/x86_64