今天看到服务器提示有漏洞需要更新，在执行更新命令的时候一直报错，因为CentOS 6操作系统版本结束了生命周期（EOL），Linux社区已不再维护该操作系统版本，导致不能正常更新。
1、背景信息：
2020年11月30日CentOS 6 EOL。按照社区规则，CentOS 6的源地址http://mirror.centos.org/centos-6/内容已移除，目前第三方的镜像站中均已移除CentOS 6的源。
2、解决方法：
（1）备份文件：
mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.backup
（2）更改CentOS-Base.repo文件：
vim /etc/yum.repos.d/CentOS-Base.repo
更改内容如下：
[base] name=CentOS-$releasever - Base #mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=os&infra=$infra baseurl=https://mirrors.aliyun.com/centos-vault/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=$infra baseurl=https://mirrors.aliyun.com/centos-vault/6.10/updates/$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=https://mirrors.aliyun.com/centos-vault/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=$infra baseurl=https://mirrors.aliyun.com/centos-vault/6.10/centosplus/$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=https://mirrors.aliyun.com/centos-vault/6.10/contrib/$basearch/ gpgcheck=1 enabled=0 gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
（3）更改epel.repo文件：
vim /etc/yum.repos.d/epel.repo
更改内容如下：
[epel] name=Extra Packages for Enterprise Linux 6 - $basearch enabled=1 failovermethod=priority baseurl=http://mirrors.aliyuncs.com/epel-archive/6/$basearch gpgcheck=0 gpgkey=http://mirrors.aliyuncs.com/epel-archive/RPM-GPG-KEY-EPEL-6
（4）yum更新：
yum -y update sudo