1.将centos8的iso文件上传到服务器
2.挂载ios
mount CentOS-8.5.2111-x86_64-dvd1.iso -o loop /mnt
3.修改CentOS-Linux-Media.repo
cd /etc/yum.repos.d
vi CentOS-Linux-Media.repo
[root@cos8 yum.repos.d]# more CentOS-Linux-Media.repo
# CentOS-Linux-Media.repo
#
# You can use this repo to install items directly off the installation media.
# Verify your mount point matches one of the below file:// paths.
[media-baseos]
name=CentOS Linux $releasever - Media - BaseOS
baseurl=file:///mnt/BaseOS
gpgcheck=1
enabled=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-centosofficial
[media-appstream]
name=CentOS Linux $releasever - Media - AppStream
baseurl=file:///mnt/AppStream
gpgcheck=1
enabled=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-centosofficial