Linode服务器安装指引中的EPEL(Extra Packages for Enterprise Linux)源现在访问有问题了，执行：
rpm -Uvh http://download.fedora.redhat.com/pub/epel/5/i386/epel-release-5-4.noarch.rpm
会报错：
error: skipping http://download.fedora.redhat.com/pub/epel/5/i386/epel-release-5-4.noarch.rpm - transfer failed - Unknown or unexpected error
下面是一些可替换的：
CentOS 6.x 32-bit (x86/i386):
rpm -Uvh http://mirror.overthewire.com.au/pub/epel/6/i386/epel-release-6-7.noarch.rpm
CentOS 6.x 64-bit (x64):
rpm -Uvh http://download.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-7.noarch.rpm
CentOS 5.x 32-bit (x86/i386):
rpm -Uvh http://dl.fedoraproject.org/pub/epel/5/i386/epel-release-5-4.noarch.rpm
CentOS 5.x 64-bit (x64):
rpm -Uvh http://dl.fedoraproject.org/pub/epel/5/x86_64/epel-release-5-4.noarch.rpm
Disable EPEL Repo:
If you want to disable the EPEL repo on your server, set “enabled=0″ in “/etc/yum.repos.d/epel.repo”:
vim /etc/yum.repos.d/epel.repo