[libvirt] [PATCHv2 0/3] Xen: Fix <clock> handling

Philipp Hahn hahn at univention.de
Tue Feb 14 17:24:35 UTC 2012


Hello Eric,

On Monday 13 February 2012 18:43:21 Eric Blake wrote:
> > 2. Instead of implementing a second variant of offset='variable' it would
> > be enough to just add an attribute reset='true' (or
> > this_is_not_from_a_buggy_libvirt_and_I_really_need_the_reset='true') to
> > dumpxml, when a driver really implements the reset semantics. As long as
> > it's missing, libvirt can convert it to reset='false' in the Xen≥3.1
> > case. With an explicit reset='true' libvirt would return an error for
> > Xen-HV≥3.1.
>
> Once we add a new attribute, we can document that domain XML that omits
> the attribute will default to hypervisor-specific choices (xen < 3.1 can
> default one way, xen >= 3.1 can default another way, and qemu can
> default in a particular way as well).  If the user provides the
> attribute, then they are requesting the specific behavior that they need.

v3 implements this as following:
 adjustment='reset' forced the old behaviour with xen; xen-3.1 will reject 
those HV-domains.
 adjustment='$timeDelta' gets directly converted to offset='variable'.

> No.  We _don't_ want a libvirt version attribute.  What we want is a new
> attribute that, if present, determines the behavior according to the
> user, and if absent, provides sane upgrade semantics when parsing older
> XML into newer libvirt.

Okay. Thank you for your explanation; makes sense.

> You still haven't managed to convince me that we cannot solve this by
> adding new attributes.

I still find it a little bit strange to add an attribute to force the parser 
to the old behaviour of utc/localtime, which was perfectly clear. But if it 
improves compatibility, I'm fine with this solution.

Thank you for your feedback so far.

BYtE
Philipp
-- 
Philipp Hahn           Open Source Software Engineer      hahn at univention.de
Univention GmbH        Linux for Your Business        fon: +49 421 22 232- 0
Mary-Somerville-Str.1  D-28359 Bremen                 fax: +49 421 22 232-99
                                                   http://www.univention.de/
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 197 bytes
Desc: This is a digitally signed message part.
URL: <http://listman.redhat.com/archives/libvir-list/attachments/20120214/ca8d5587/attachment-0001.sig>


More information about the libvir-list mailing list