yum源更新后需要導入key值，否則報錯如下，無法安裝相關的包。
Totalsize:42M
DownloadingPackages:
warning:rpmts_HdrFromFdno:HeaderV3RSA/SHA1Signature,keyIDc105b9de:NOKEY
Retrievingkeyfromfile:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
GPGkeyretrievalfailed:[Errno14]Couldnotopen/readfile:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
解決辦法：
先安裝如下工具包：
rpm-Uhvhttp://dag.wieers.com/packages/rpmforge-release/rpmforge-release-0.3.4-1.el4.rf.i386.rpm
[root@localhostyum.repos.d]#rpm--import/etc/pki/rpm-gpg/RPM-GPG-KEY-6
一般來說安裝完成后即可，安裝完這個就可以了。
如果還是不行，查看系統的
編輯yum源文件：替換RPM-GPG-KEY-CentOS-5替換為對應的key文件名：RPM-GPG-KEY-CentOS-6（要全部替換）
root@localhostyum.repos.d]#viCentOS-Base-sohu.repo
[base]
name=CentOS-$releasever-Base-sohu.com
mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=os
baseurl=http://mirrors.sohu.com/centos/$releasever/os/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
author gj