[Pkg-libvirt-maintainers] Bug#698093: Bug#698093: libvirt-bin: Enable Xen libxl backend

[小龙 陈]

> Date: Sun, 20 Jan 2013 10:26:42 +0100
> From: agx at sigxcpu.org
> To: chillermillerlong at hotmail.com
> CC: 698093 at bugs.debian.org
> Subject: Re: [Pkg-libvirt-maintainers] Bug#698093: libvirt-bin: Enable Xen libxl backend
> 
> On Sun, Jan 20, 2013 at 04:06:12AM -0500, 小龙 陈 wrote:
> > > Date: Mon, 14 Jan 2013 08:14:46 +0100
> > > From: agx at sigxcpu.org
> > > To: chillermillerlong at hotmail.com; 698093 at bugs.debian.org
> > > Subject: Re: [Pkg-libvirt-maintainers] Bug#698093: libvirt-bin: Enable Xen libxl backend
> > > 
> > > On Sun, Jan 13, 2013 at 07:05:12PM -0500, Xiao-Long Chen wrote:
> > > > Package: libvirt-bin
> > > > Version: 1.0.0-0ubuntu4ppa1~raring1
> > > 
> > > Please don't file bugs against Ubuntu versions.
> > Sorry about that. I should have read the guidelines for bug reporting in Debian.
> > > 
> > > > Severity: normal
> > > > 
> > > > Please enable the libxl backend for Xen in libvirt. Version 1.0.0 and above
> > > > support this backend. Xen is already deprecating the old xm/xend toolstack in
> > > > Xen 4.2 and is moving to the xl toolstack.
> > > 
> > > It's not that simple. We need to offer a migration path for existing
> > > configurations. Do you want to work on that?
> > > Cheers,
> > > -- Guido
> > > 
> > 
> > Would migration be necessary? As far as I know, libvirt will
> > automaticallyfall back to the current xen driver if xend is running.
> > It will only use xl ifxend is not started. > Am I correct to assume
> Did you try this? Last time I checked the libxml driver would take
> precedence over xend.
>

I've tried it in another distro, but I haven't tested it in Debian yet. I'll
test it later today. But if you look at the source code:

http://libvirt.org/git/?p=libvirt.git;a=blob;f=src/libxl/libxl_driver.c;h=a8c4cae0e509a09e76ea344e3c0826cea04bfd71;hb=HEAD#l971

On line 971, libvirt will run "/usr/sbin/xend status" to check if xend is
running. If so, libxl falls back to xend.

Of course, just because something is in the source doesn't mean it works
correctly :) I'll test it to make sure.

Cheers,
Xiao-Long Chen

> > that any existing libvirt configuration for xen wouldhave xend started
> > automatically as it is required?
> No. Libvirt doesn't setup the hypervisor it "only" looks for available
> ones.
> Cheers,
> -- Guido
> 
> > Cheers,Xiao-Long Chen