执行yum install vconfig时老是报错：

http://vault.centos.org/centos/7/os/Source/repodata/repomd.xml: [Errno 14] HTTP Error 404 - Not Found

经过分析：

原因是标准的CentOS 7.0 Build1406里面很多的仓库已经被CentOS移除了，转到CentOS 7.1 Build1503和CentOS7.2 Build1503了。

因此需要手工更改仓库文件/etc/yum.d.repo/CentOS-Sources.repo，

更改之前，先备份下

#cp CentOS-Sources.repo CentOS-Sources.repo.bak

然后开始编辑CentOS-Sources.repo文件。

将文件中的“$releasever”全部替换成“7.2.1511”或者“7.1.1503”。

[base-source]
name=CentOS-7.2.1511 - Base Sources
baseurl=http://vault.centos.org/centos/7.2.1511/os/Source/
gpgcheck=1
enabled=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7

#released updates
[updates-source]
name=CentOS-7.2.1511 - Updates Sources
baseurl=http://vault.centos.org/centos/7.2.1511/updates/Source/
gpgcheck=1
enabled=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7

#additional packages that may be useful
[extras-source]
name=CentOS-7.2.1511 - Extras Sources
baseurl=http://vault.centos.org/centos/7.2.1511/extras/Source/
gpgcheck=1
enabled=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7

#additional packages that extend functionality of existing packages
[centosplus-source]
name=CentOS-7.2.1511 - Plus Sources
baseurl=http://vault.centos.org/centos/7.2.1511/centosplus/Source/
gpgcheck=1
enabled=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7

更改完成后执行

#yum clean

#yum update