mkdir /home/media
mout -t iso9660 -o loop /home/soft/Centos.iso /home/media
vi /etc/yum.repos.d/CentOS7-Localsource.repo
[CentOS7-Localsource]
name=CentOS7
baseurl=file:///home/media
enabled=1
gpgcheck=0
改名备份
mv etc/yum.repos.d/CentOS-Base.repo bak
#yum clean all
#yum makecache