How to install additional CentOS packages on XenServer 6.2

  While it is unsupported, it can sometimes be quite handy to install additional packages on your XenServer 6.2 system – things like vim, iptraf, perhaps even denyhosts. By default extra packages you wish to install are likely disabled, but using yum we can temporarily allow access to the CentOS packages. Logging in as root and using yum we can:  
yum –enablerepo=base –disablerepo=citrix install [packagename]
As an example, using denyhosts:
yum –enablerepo=base –disablerepo=citrix install denyhosts
Doing this is totally unsupported and, depending on the package(s) installed may break the entire XenServer install – so experiment at your own risk!