Re: UML->Xen laundry list

[Mike Wray <mike.wray@hpl.hp.com>]

Matthew Bloch wrote:
> Hello,
> 
> I'm nearly finished converting our hosting scripts (in Ruby) to work 
> with Xen as well as UML so wondered whether I could solicit some 
> miscellaneous comments on my remaining jobs.   I appreciate there may be 
> (yet) no official way to do any of these, but I'd appreciate pointers to 
> the relevant bits of source or any other relevant discussion.  The 
> reason is I'm keen to make a few hacks to the user-space tools to better 
> integrate with our existing scripts, not because I'm just poking around 
> in lower level interfaces for fun (though I am having fun :) ).
> 
> How to send a Ctrl+Alt+Delete (or sysrq) to a XenLinux guest kernel?
> 
> How to create a vif interface from dom0, supply it pre-configured to a 
> domain?

At the moment you can't - the vif interfaces in dom0 are created by
the back-end network drivers. You could modify /etc/xen/scripts/vif-bridge
or configure a different script if you need to do stuff to the vif.

> 
> Disc synchronisation: when specifying a block device as a file: from a 
> Linux domain 0, does the back-end driver in dom0 cache disc writes from 
> other domains?  i.e. if power is lost, could the journalled filesystems 
> in other domains become corrupted?  I'm guessing the answer is "no" but 
> this is just one of those avoidable hazards of UML that I wish to avoid 
> again if possible.
> 
> Where in the libxc C interface can I find the name of a domain?  I know 
> I probably shouldn't be using this interface, I'm just curious.  (there 
> must be a better way than grovelling around in /var/xen)

You can't. Xen doesn't know the names of domains (well not the full names
anyway), only xend knows what the domain names are.

> 
> Finally any docs on the sxp libraries: purpose and formats would be 
> greatly appreciated.  I assume it's a light cross-language data 
> serialization library but haven't dug very deeply yet.

It's documented in docs/misc/xen_config.html (and possibly elsewhere).
Basically it's a lisp coding of xml.

Mike


-------------------------------------------------------
SF email is sponsored by - The IT Product Guide
Read honest & candid reviews on hundreds of IT Products from real users.
Discover which products truly live up to the hype. Start reading now. 
http://productguide.itmanagersjournal.com/