一、CentOS6停止维护更新日期2020年11月30日
centos 6 已于2020年12月2日停更，原yum源也不能用了。
原先默认的yum源地址是mirrorlist=http://mirrorlist.centos.org/
二、2020年12月2日下架了包括官方所有的CentOS6源（包括国内的镜像站）
我们可以通过更新baseurl来解决。
解决方法：
1.通过修改CentOS-Base.repo文件中的源地址来处理
vi /etc/yum.repos.d/CentOS-Base.repo
将原mirrorlist行注释掉，并在原baseurl下分别添加新的源地址。
新的源地址为http://vault.centos.org，如操作系统是6.10可以找对应的源。
最终更改CentOS-Base.repo文件内容如下。
# CentOS-Base.repo # # The mirror system uses the connecting IP address of the client and the # update status of each mirror to pick mirrors that are updated to and # geographically close to the client. You should use this for CentOS updates # unless you are manually picking other mirrors. # # If the mirrorlist= does not work for you, as a fall back you can try the # remarked out baseurl= line instead. # # [base] name=CentOS-$releasever - Base #mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=os&infra=$infra #baseurl=http://mirror.centos.org/centos/$releasever/os/$basearch/ baseurl=http://vault.centos.org/6.10/os/$basearch/ gpgcheck=1 gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6 #released updates [updates] name=CentOS-$releasever - Updates #mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=updates&infra=$infra #baseurl=http://mirror.centos.org/centos/$releasever/updates/$basearch/ baseurl=http://vault.centos.org/6.10/updates/$basearch/ gpgcheck=1 gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6 #additional packages that may be useful [extras] name=CentOS-$releasever - Extras #mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=extras&infra=$infra #baseurl=http://mirror.centos.org/centos/$releasever/extras/$basearch/ baseurl=http://vault.centos.org/6.10/extras/$basearch/ gpgcheck=1 gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6 #additional packages that extend functionality of existing packages [centosplus] name=CentOS-$releasever - Plus #mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=centosplus&infra=$infra #baseurl=http://mirror.centos.org/centos/$releasever/centosplus/$basearch/ baseurl=http://vault.centos.org/6.10/centosplus/$basearch/ gpgcheck=1 enabled=0 gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6 #contrib - packages by Centos Users [contrib] name=CentOS-$releasever - Contrib #mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=contrib&infra=$infra #baseurl=http://mirror.centos.org/centos/$releasever/contrib/$basearch/ baseurl=http://vault.centos.org/6.10/contrib/$basearch/ gpgcheck=1 enabled=0 gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
文件修改完毕并保存。
2：执行清空yum源缓存。完成后即可正常使用yum命令了。
yum clean all && yum makecache