Because the company i'm working for is a Citrix partner and that Citrix wants us to become Xen partner (since Citrix acquired XenSource several months ago), i decided to download and test their XenServer on a IBM HS21 quad-core. Funny that to administer Xen graphically you need to use their .Net application on Windows .. and no Linux console available ! (while i remember that on previous version a java and so cross-platform version was available).
But the thing that surprized me more is that they are using CentOS packages for a lot of RPMS on the Dom0 ! In fact , i wanted directly to ssh in the xen box to see what was inside and `uname -a` answered me : Linux xen 2.6.18-8.1.8.el5.xs126.96.36.199.163xen #1 SMP Mon Aug 13 09:27:46 EDT 2007 i686 i686 i386 GNU/Linux ... That sounded very familiar to me ... so from where does the rest of the system come ? : rpm -qai|grep "Vendor: CentOS"|wc -l : 185 (out of 220 packages) ..
In fact, even the standard CentOS-Base.repo and CentOS-Media.repo are still in /etc/yum.repos.d/ (but they are modified to exclude kernel and xen packages) . The CentOS repositories are disabled by default but you can use them to install other centos packages on the XenServer Dom0 ...
Funny, isn't it ? ;-)