centos系统老版本的yum源官方会定期结束维护，如果还想使用老系统并且使用yum源，需要修改为centos-vault的源。
这里以centos6.10为例。
- 备份原来的repo文件
# cp /etc/yum.repos.d/CentOS-Base.repo{.bak}
- 将如下代码贴进新的repo文件：
# 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-$releasever - Base - mirrors.aliyun.com
failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos-vault/6.10/os/$basearch/
http://mirrors.aliyuncs.com/centos-vault/6.10/os/$basearch/
http://mirrors.cloud.tencent.com/centos/$releasever/os/$basearch/
http://mirrors.tencentyun.com/centos/$releasever/os/$basearch/
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=os
gpgcheck=1
gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-6
#released updates
[updates]
name=CentOS-$releasever - Updates - mirrors.aliyun.com
failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos-vault/6.10/updates/$basearch/
http://mirrors.aliyuncs.com/centos-vault/6.10/updates/$basearch/
http://mirrors.cloud.tencent.com/centos/$releasever/updates/$basearch/
http://mirrors.tencentyun.com/centos/$releasever/updates/$basearch/
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=updates
gpgcheck=1
gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-6
#additional packages that may be useful
[extras]
name=CentOS-$releasever - Extras - mirrors.aliyun.com
failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos-vault/6.10/extras/$basearch/
http://mirrors.aliyuncs.com/centos-vault/6.10/extras/$basearch/
http://mirrors.cloud.tencent.com/centos/$releasever/extras/$basearch/
http://mirrors.tencentyun.com/centos/$releasever/extras/$basearch/
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=extras
gpgcheck=1
gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-6
#additional packages that extend functionality of existing packages
[centosplus]
name=CentOS-$releasever - Plus - mirrors.aliyun.com
failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos-vault/6.10/centosplus/$basearch/
http://mirrors.aliyuncs.com/centos-vault/6.10/centosplus/$basearch/
http://mirrors.cloud.tencent.com/centos/$releasever/centosplus/$basearch/
http://mirrors.tencentyun.com/centos/$releasever/centosplus/$basearch/
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=centosplus
gpgcheck=1
enabled=0
gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-6
#contrib - packages by Centos Users
[contrib]
name=CentOS-$releasever - Contrib - mirrors.aliyun.com
failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos-vault/6.10/contrib/$basearch/
http://mirrors.aliyuncs.com/centos-vault/6.10/contrib/$basearch/
http://mirrors.cloud.tencent.com/centos/$releasever/contrib/$basearch/
http://mirrors.tencentyun.com/centos/$releasever/contrib/$basearch/
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=contrib
gpgcheck=1
enabled=0
gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-6
- 清除就缓存，建立新缓存
# yum clean all
Loaded plugins: security
Cleaning repos: base extras updates
Cleaning up Everything
# yum makecache
Loaded plugins: security
base | 3.7 kB 00:00
base/group_gz | 242 kB 00:00
base/filelists_db | 6.4 MB 00:01
base/primary_db | 4.7 MB 00:01
base/other_db | 2.8 MB 00:00
extras | 3.4 kB 00:00
extras/filelists_db | 24 kB 00:00
extras/prestodelta | 2.2 kB 00:00
extras/primary_db | 29 kB 00:00
extras/other_db | 14 kB 00:00
updates | 3.4 kB 00:00
updates/filelists_db | 8.4 MB 00:02
updates/prestodelta | 357 kB 00:00
updates/primary_db | 12 MB 00:03
updates/other_db | 479 kB 00:00
#yum makecache