Re: XEN migration architecture question

[Jacob Gorm Hansen <jacobg@diku.dk>]

B.G. Bruce wrote:
> Interesting ....
> So, what are you using in DOM0 as a watchdog to make sure all the proper
> domU domains are up and functional?  Or how do you go about this?

My setup is nontypical, in that I do not allow much remote 
administration, everything happens within the unprivileged domains. 
Basically, all you can do is bootstrap or migrate a domain into an 
existing domU, and you need to keep feeding it 'tokens' for it to stay 
alive, or it will be destroyed.

My payment model is like for a Laundromat; you feed it tokens, it solves 
your problem. If you don't like the laundromat (if it is too slow or too 
expensive), you move your laundry to a different one and start feeding 
that one your tokens instead. You don't have to call some 
superuser-person to move the laundry for you.

All bootstrap and migration, apart from the initial part where an almost 
empty VM gets instantiated, happens inside domUs. I have modified Linux 
to be self-migrating, so I do not use the standard Xen migration mechanism.

If you have hundreds or thousands of machines, you do not wish to 
periodically log in to each one's dom0 to see if things are going as 
expected. If a VM goes missing, you restart the VM or you restore it 
from a checkpoint, both of which can be handled remotely.

I do have some network-facing code in dom0, but that is only around 100 
lines of C, mostly related to answering ARP and ICMP Echo requests. The 
rest (e.g. TCP/IP) runs within my domUs.

More info at
http://www.diku.dk/~jacobg/self-migration/

Jacob


-------------------------------------------------------
This SF.Net email is sponsored by: IntelliVIEW -- Interactive Reporting
Tool for open source databases. Create drag-&-drop reports. Save time
by over 75%! Publish reports on the web. Export to DOC, XLS, RTF, etc.
Download a FREE copy at http://www.intelliview.com/go/osdn_nl