CentOS6 yum 404问题

昨天安装了一台CentOS6的服务器，发现yum不可用了，错误信息如下：
Determining fastest mirrors
YumRepo Error: All mirror URLs are not using ftp, http[s] or file.
Eg. Invalid release/repo/arch combination/
removing mirrorlist with no valid mirrors: /var/cache/yum/x86_64/6/base/mirrorlist.txt
错误：Cannot find a valid baseurl for repo: base
前面怀疑是服务器的网络问题，经排查网络无异常，拿yum源中的地址确认问题，发现404了，地址已经发发生了改变，原因是CentOS 6已经随着2020年11月的结束进入了EOL（Reaches End of Life），官方便在12月2日正式将CentOS 6相关的软件源移出了官方源，随之而来逐级镜像也会陆续将其删除。虽然CentOS已经发布到了8版本，但是依然还是有一些老系统在使用CentOS6，还是保留了各个版本软件源的镜像，只是这个软件源不会再有更新了，地址也发生了改变。下面介绍重新配置yum源。

- 备份文件

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

- 替换CentOS-Base.repo文件内容

下面提供了官方Vault源和阿里云Vault镜像，选择其一即可，国内建议使用阿里云Vault镜像，速度会更快。
vi /etc/yum.repos.d/CentOS-Base.repo

#阿里云Vault镜像，本例使用的6.10版本，注意修改为你当前的操作系统版本号
[base]
name=CentOS-6.10 - Base - mirrors.aliyun.com
failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos-vault/6.10/os/$basearch/
gpgcheck=1
gpgkey=http://mirrors.aliyun.com/centos-vault/RPM-GPG-KEY-CentOS-6
 
#released updates 
[updates]
name=CentOS-6.10 - Updates - mirrors.aliyun.com
failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos-vault/6.10/updates/$basearch/
gpgcheck=1
gpgkey=http://mirrors.aliyun.com/centos-vault/RPM-GPG-KEY-CentOS-6
 
#additional packages that may be useful
[extras]
name=CentOS-6.10 - Extras - mirrors.aliyun.com
failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos-vault/6.10/extras/$basearch/
gpgcheck=1
gpgkey=http://mirrors.aliyun.com/centos-vault/RPM-GPG-KEY-CentOS-6
 
#additional packages that extend functionality of existing packages
[centosplus]
name=CentOS-6.10 - Plus - mirrors.aliyun.com
failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos-vault/6.10/centosplus/$basearch/
gpgcheck=1
enabled=0
gpgkey=http://mirrors.aliyun.com/centos-vault/RPM-GPG-KEY-CentOS-6
 
#contrib - packages by Centos Users
[contrib]
name=CentOS-6.10 - Contrib - mirrors.aliyun.com
failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos-vault/6.10/contrib/$basearch/
gpgcheck=1
enabled=0
gpgkey=http://mirrors.aliyun.com/centos-vault/RPM-GPG-KEY-CentOS-6



--官方Vault源，本例使用的6.10版本，注意修改为你当前的操作系统版本号
[base]
name=CentOS-6.10 - Base - vault.centos.org
failovermethod=priority
baseurl=http://vault.centos.org/6.10/os/$basearch/
gpgcheck=1
gpgkey=http://vault.centos.org/RPM-GPG-KEY-CentOS-6
 
#released updates 
[updates]
name=CentOS-6.10 - Updates - vault.centos.org
failovermethod=priority
baseurl=http://vault.centos.org/6.10/updates/$basearch/
gpgcheck=1
gpgkey=http://vault.centos.org/RPM-GPG-KEY-CentOS-6
 
#additional packages that may be useful
[extras]
name=CentOS-6.10 - Extras - vault.centos.org
failovermethod=priority
baseurl=http://vault.centos.org/6.10/extras/$basearch/
gpgcheck=1
gpgkey=http://vault.centos.org/RPM-GPG-KEY-CentOS-6
 
#additional packages that extend functionality of existing packages
[centosplus]
name=CentOS-6.10 - Plus - vault.centos.org
failovermethod=priority
baseurl=http://vault.centos.org/6.10/centosplus/$basearch/
gpgcheck=1
enabled=0
gpgkey=http://vault.centos.org/RPM-GPG-KEY-CentOS-6
 
#contrib - packages by Centos Users
[contrib]
name=CentOS-6.10 - Contrib - vault.centos.org
failovermethod=priority
baseurl=http://vault.centos.org/6.10/contrib/$basearch/
gpgcheck=1
enabled=0
gpgkey=http://vault.centos.org/RPM-GPG-KEY-CentOS-6

清除YUM缓存
yum clean all
重新构建缓存
yum makecache

虽然更换Vault源能够保证系统基础功能正常，但是已经进入EOL的系统失去了官方的更新和维护，日后有可能会因为一些漏洞而被入侵，如果可以的话还是建议更新到最新版本受支持的系统。