Re: xen confusion

[Paul Leiber <paul@xxxxxxxxxxxxxxxx>]

Am 18.09.26 um 01:18 schrieb Leroy Tennison:
> In my research concerning the xen hypervisor I not only find the xen project but xenserver 
> (Citrix?), xcp-ng, xenbits and other references.  I installed the3 xen-system-amd64 from 
> Debian Trixie which I'm assum,ing is the xen project.  What is the difference in all 
> these variants?  Thanks for your help.
Hi Leroy,

Welcome to the Xen world! Here's my understanding.

First of all, Xenbits stands out from your list because it is not a software, 
but a part of the official Xen homepage. It lists other sites and repositories 
related to Xen. Understanding that you are looking for a hypervisor software 
solution, I am not going into more detail on Xenbits.

Xen is an open source hypervisor. Xen is the basis for all the virtualization 
solutions you have mentioned. Xen needs a toolstack (i.e. management tools) to 
tell it what to do. There are different toolstacks available.

(Vanilla) Xen uses xl, a command line interface, as its management tool. It can 
do everything you need and then more, but it takes some time to get familiar 
with. It is what I have been using for many years now. Xen is available on many 
distributions, e. g. through the Debian package you have mentioned. Xen 
including the toolstack is completely open source.

Xenserver is a commercial hypervisor solution from Citrix, based on the Xen 
hypervisor, but using a different toolstack with a GUI. I have never used it. 
There are some things Xenserver can do out of the box which Xen doesn't (yet), 
e. g. boot a guest (or DomU, as guest VMs are called in Xen terminology) which 
requires TPM support. Parts of Xenserver are closed source. I think there is a 
free version of Xenserver available which is restricted somehow.

XCP-ng is another toolstack based on Xen, also with a GUI for hypervisor 
management. It is part of a complete linux distribution with the purpose of 
running and managing VMs. It is also open source. Commercial support is 
available for XCP-ng. I have never used it.

I think that it is important to give Xen newbies a good welcome, that's why I 
wrote this answer. However, I want to point out to you that all this 
information is rather easy to find, e. g. by reading the Wikipedia sites [1][2] 
or the official Xenserver homepage [3]. I suggest to spend some time reading 
these and also some articles on the official Xen wiki.

Specifically, I still find that the official Xen wiki howto [4] is a good 
starting point for learning how to use vanilla Xen with Debian as a Dom0, even 
if some information in the wiki is outdated.

Have fun!

Paul

[1] https://en.wikipedia.org/wiki/Xen
[2] https://en.wikipedia.org/wiki/XCP-ng
[3] https://www.xenserver.com/story
[4] https://wiki.xenproject.org/wiki/Xen_Project_Beginners_Guide