Centos换yum源

yum报错

Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
Could not retrieve mirrorlist http://mirrorlist.centos.org/?release=7&arch=x86_64&repo=os&infra=stock error was
14: curl#6 - "Could not resolve host: mirrorlist.centos.org; Unknown error"

查看版本号

cat /etc/issue
cat /etc/redhat-release

修改源

cp /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.bak #备份
vi /etc/yum.repos.d/CentOS-Base.repo

修改成vault.centos.org

[base]
name=CentOS-$releasever - Base
baseurl=http://vault.centos.org/7.7.1908/os/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7 
[updates]
name=CentOS-$releasever - Updates
baseurl=http://vault.centos.org/7.7.1908/updates/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7 
[extras]
name=CentOS-$releasever - Extras
baseurl=http://vault.centos.org/7.7.1908/extras/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7

清空缓存生成缓存

yum clean all && yum makecache