我有一台阿里云的Linux服务器，安装的是CenTos6.9，刚才在使用yum upgrade和yum update进行更新的时候，返回以下错误信息，更新不能够进行。

Downloading Packages:
http://mirrors.cloud.aliyuncs.com/centos/6/updates/x86_64/Packages/kernel-2.6.32-754.35.1.el6.x86_64.rpm: [Errno 14] PYCURL ERROR 22 - "The requested URL returned error: 404 Not Found"
Trying other mirror.
http://mirrors.cloud.aliyuncs.com/centos/6/updates/x86_64/Packages/kernel-devel-2.6.32-754.35.1.el6.x86_64.rpm: [Errno 14] PYCURL ERROR 22 - "The requested URL returned error: 404 Not Found"
Trying other mirror.
http://mirrors.cloud.aliyuncs.com/centos/6/updates/x86_64/Packages/kernel-firmware-2.6.32-754.35.1.el6.noarch.rpm: [Errno 14] PYCURL ERROR 22 - "The requested URL returned error: 404 Not Found"
Trying other mirror.
http://mirrors.cloud.aliyuncs.com/centos/6/updates/x86_64/Packages/kernel-headers-2.6.32-754.35.1.el6.x86_64.rpm: [Errno 14] PYCURL ERROR 22 - "The requested URL returned error: 404 Not Found"
Trying other mirror.
http://mirrors.cloud.aliyuncs.com/centos/6/updates/x86_64/Packages/libX11-1.6.4-4.el6_10.x86_64.rpm: [Errno 14] PYCURL ERROR 22 - "The requested URL returned error: 404 Not Found"
Trying other mirror.
http://mirrors.cloud.aliyuncs.com/centos/6/updates/x86_64/Packages/libX11-common-1.6.4-4.el6_10.noarch.rpm: [Errno 14] PYCURL ERROR 22 - "The requested URL returned error: 404 Not Found"
Trying other mirror.
http://mirrors.cloud.aliyuncs.com/centos/6/updates/x86_64/Packages/libX11-devel-1.6.4-4.el6_10.x86_64.rpm: [Errno 14] PYCURL ERROR 22 - "The requested URL returned error: 404 Not Found"
Trying other mirror.
http://mirrors.cloud.aliyuncs.com/centos/6/updates/x86_64/Packages/tzdata-2020d-1.el6.noarch.rpm: [Errno 14] PYCURL ERROR 22 - "The requested URL returned error: 404 Not Found"
Trying other mirror.


Error Downloading Packages:
  kernel-devel-2.6.32-754.35.1.el6.x86_64: failure: Packages/kernel-devel-2.6.32-754.35.1.el6.x86_64.rpm from updates: [Errno 256] No more mirrors to try.
  tzdata-2020d-1.el6.noarch: failure: Packages/tzdata-2020d-1.el6.noarch.rpm from updates: [Errno 256] No more mirrors to try.
  kernel-2.6.32-754.35.1.el6.x86_64: failure: Packages/kernel-2.6.32-754.35.1.el6.x86_64.rpm from updates: [Errno 256] No more mirrors to try.
  libX11-devel-1.6.4-4.el6_10.x86_64: failure: Packages/libX11-devel-1.6.4-4.el6_10.x86_64.rpm from updates: [Errno 256] No more mirrors to try.
  libX11-common-1.6.4-4.el6_10.noarch: failure: Packages/libX11-common-1.6.4-4.el6_10.noarch.rpm from updates: [Errno 256] No more mirrors to try.
  libX11-1.6.4-4.el6_10.x86_64: failure: Packages/libX11-1.6.4-4.el6_10.x86_64.rpm from updates: [Errno 256] No more mirrors to try.
  kernel-headers-2.6.32-754.35.1.el6.x86_64: failure: Packages/kernel-headers-2.6.32-754.35.1.el6.x86_64.rpm from updates: [Errno 256] No more mirrors to try.
  kernel-firmware-2.6.32-754.35.1.el6.noarch: failure: Packages/kernel-firmware-2.6.32-754.35.1.el6.noarch.rpm from updates: [Errno 256] No more mirrors to try.

在阿里云的帮助文档里得知，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。建议您升级操作系统至CentOS 7及以上，如果您的业务过渡期仍需要使用CentOS 6系统中的一些安装包，请根据下文切换CentOS 6的源。

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。阿里云的源http://mirrors.cloud.aliyuncs.com和http://mirrors.aliyun.com也无法同步到CentOS 6的源。当您在阿里云上继续使用默认配置的CentOS 6的源会发生报错。报错示例如下图所示：centos 6 error

您可以通过下文的操作步骤，在CentOS 6操作系统的ECS实例中将源配置按照网络环境不同进行切换。

yum源
专有网络VPC类型实例需切换为http://mirrors.cloud.aliyuncs.com/centos-vault/6.10/源。
经典网络类型实例需切换为http://mirrors.aliyuncs.com/centos-vault/6.10/源。
epel源
专有网络VPC类型实例需切换为http://mirrors.cloud.aliyuncs.com/epel-archive/6/源。
经典网络类型实例需切换为http://mirrors.aliyuncs.com/epel-archive/6/源。

运行以下命令编辑CentOS-Base.repo 文件。

vim /etc/yum.repos.d/CentOS-Base.repo

按i进入编辑模式，修改以下内容切换源。
请根据实例不同的网络类型进行修改，具体内容如下：

专有网络VPC类型实例

[base]
name=CentOS-6.10
enabled=1
failovermethod=priority
baseurl=http://mirrors.cloud.aliyuncs.com/centos-vault/6.10/os/$basearch/
gpgcheck=1
gpgkey=http://mirrors.cloud.aliyuncs.com/centos-vault/RPM-GPG-KEY-CentOS-6

[updates]
name=CentOS-6.10
enabled=1
failovermethod=priority
baseurl=http://mirrors.cloud.aliyuncs.com/centos-vault/6.10/updates/$basearch/
gpgcheck=1
gpgkey=http://mirrors.cloud.aliyuncs.com/centos-vault/RPM-GPG-KEY-CentOS-6

[extras]
name=CentOS-6.10
enabled=1
failovermethod=priority
baseurl=http://mirrors.cloud.aliyuncs.com/centos-vault/6.10/extras/$basearch/
gpgcheck=1
gpgkey=http://mirrors.cloud.aliyuncs.com/centos-vault/RPM-GPG-KEY-CentOS-6

经典网络类型实例

[base]
name=CentOS-6.10
enabled=1
failovermethod=priority
baseurl=http://mirrors.aliyuncs.com/centos-vault/6.10/os/$basearch/
gpgcheck=1
gpgkey=http://mirrors.aliyuncs.com/centos-vault/RPM-GPG-KEY-CentOS-6

[updates]
name=CentOS-6.10
enabled=1
failovermethod=priority
baseurl=http://mirrors.aliyuncs.com/centos-vault/6.10/updates/$basearch/
gpgcheck=1
gpgkey=http://mirrors.aliyuncs.comm/centos-vault/RPM-GPG-KEY-CentOS-6

[extras]
name=CentOS-6.10
enabled=1
failovermethod=priority
baseurl=http://mirrors.aliyuncs.com/centos-vault/6.10/extras/$basearch/
gpgcheck=1
gpgkey=http://mirrors.aliyuncs.com/centos-vault/RPM-GPG-KEY-CentOS-6

编辑完成后，按Esc键，并输入:wq保存退出文件。

运行以下命令编辑epel.repo 文件。

vim /etc/yum.repos.d/epel.repo

按i进入编辑模式，修改以下内容切换源。
请根据实例不同的网络类型进行修改，具体内容如下：

专有网络VPC类型实例

[epel]
name=Extra Packages for Enterprise Linux 6 - $basearch
enabled=1
failovermethod=priority
baseurl=http://mirrors.cloud.aliyuncs.com/epel-archive/6/$basearch
gpgcheck=0
gpgkey=http://mirrors.cloud.aliyuncs.com/epel-archive/RPM-GPG-KEY-EPEL-6

经典网络类型实例

[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

编辑完成后，按Esc键，并输入:wq保存退出文件。
切换完成后，您可以使用yum upgrade或yum update命令安装需要的软件包。