後來發現是因為repo 太舊了...只好把centos 5 的repo換掉
就可以更新yum 安裝檔案了
記得要先把citrix.repo enable=1 改成 0
/etc/yum.repos.d
然後把CentOS-Base.repo 改成下面新的就可以正常更新安裝了
[base]
name=CentOS-$releasever - Base
baseurl=http://vault.centos.org/5.11/os/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-5
#released updates
[updates]
name=CentOS-$releasever - Updates
baseurl=http://vault.centos.org/5.11/updates/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-5
#additional packages that may be useful
[extras]
name=CentOS-$releasever - Extras
baseurl=http://vault.centos.org/5.11/extras/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-5
