Re: [Xen-API] Xen-API Preview Tree

["Daniel P. Berrange" <berrange@xxxxxxxxxx>]

Hi Ewan,

I see the XenAPI work has been merged into xen-devel now, but none of
the 3 issues detailed below have been addressed which is going to cause
some compatability problems for existing clients.

Regards,
Dan.

On Mon, Oct 09, 2006 at 11:45:35PM +0100, Ewan Mellor wrote:
> On Mon, Oct 09, 2006 at 06:47:37PM +0100, Daniel P. Berrange wrote:
> 
> > With the lifecycle patches, 'xm list' and 'GET /xend/domains' will now
> > include inactive domains as well as active domains. eg
> > 
> >   # xm list
> >   Name                              ID Mem(MiB) VCPUs State  Time(s)
> >   Domain-0                           0      594     2 r-----    22.2
> >   guest3                            -1      400     1 ------    14.7
> > 
> > This can cause a slight compatability problem because there has previously
> > been the tacit assumption that "ID" is a unique way to refer to a domain
> > running on a box. With all inactive domains now returning '-1' this is no
> > longer valid. So I think that returning inactive domains by default for
> > commands line 'xm list' or the raw  'GET /xend/domains' may well cause
> > compatability problems for existing users of this command / API. 
> 
> Note that the domain ID is a unique identifier for the domain, but _not_ a
> unique identifier for a VM.  If a VM is migrating to localhost, for example,
> then a given VM may have two different domain IDs.
> 
> That said, I certainly agree that the change in semantics of the old protocol
> is inappropriate, and I'll put that on the list to be fixed.  Your
> proposal for a flag to xm list sounds fine to me also (though I'm
> tempted to word it as "state=Running" rather than "scope=active", to
> reuse the existing VM state mechanisms).  Regardless of the details, the
> basic idea is sound, and we'll put that in certainly.
> 
> > In the actual listing of domains in XM, I think its probably more desirable
> > to just have a '-' in the ID column for inactive domains, rather than -1,s
> > since this indicates more clearly that there is no effective ID for inactive
> > domains, eg 
> > 
> >   # xm list
> >   Name                              ID Mem(MiB) VCPUs State  Time(s)
> >   Domain-0                           0      594     2 r-----    22.2
> >   guest3                             -      400     1 ------    14.7
> 
> Sure, sounds fine.
> 
> > Finally, I'd also like to see the 'xend_config_version' field for 'xm info'
> > incremented from '2' to '3' to allow clients to easily detect that the XenD
> > they're talking to has this new capability for configs.
> 
> Definitely.
> 
> Thanks for that,
> 
> Ewan.

-- 
|=- Red Hat, Engineering, Emerging Technologies, Boston.  +1 978 392 2496 -=|
|=-           Perl modules: http://search.cpan.org/~danberr/              -=|
|=-               Projects: http://freshmeat.net/~danielpb/               -=|
|=-  GnuPG: 7D3B9505   F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505  -=| 

_______________________________________________
xen-api mailing list
xen-api@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-api