[libvirt] RE: Re: kvm-81: save / restore does not work - missing incoming stdio feature

[Richard W.M. Jones]

On Thu, Jan 22, 2009 at 12:10:51PM +0000, Daniel P. Berrange wrote:
> On Mon, Jan 19, 2009 at 01:01:15PM +0000, Daniel P. Berrange wrote:
> > On Mon, Jan 19, 2009 at 01:53:48PM +0100, Daniel Schwager wrote:
> > > Hi Daniel,
> > > 
> > > Charles Duffy (thanks Charles !) told me how to fix libvirt for using
> > > the
> > > new "-incoming" API - yust replace "stdio" with "exec:cat" ..
> > > 
> > > Works like a charm,  tested with FC9, libvirt.0.5.1-2 and KVM-83
> > 
> > Unfortunately things are not that simple. This will work for new KVM, but
> > break for older KVM which only supports 'stdio:', 'file://' and 'tcp://'
> > for incoming migration. There needs to be some kind of version / support
> > check here to decide which syntax to use.
> 
> The version check is quite tricky due to soo many combinations. So I've
> created some test scripts to check we're doing it right. This patch should
> make restore work again,  by detecting if 'exec' is supported and then
> doing an automatic conversion from 'stdio' to 'exec:cat' in this case.
> It also prints clear error messages if it finds a QEMU which doesn't
> have the neccessary support - likewise detecting old KVM where the
> TCP migration wouldn't work correctly, just hanging on startup.
> 
>  b/tests/qemuxml2argvdata/qemuxml2argv-migrate.args    |    1 
>  b/tests/qemuxml2argvdata/qemuxml2argv-migrate.xml     |   22 +++++++++
>  b/tests/qemuxml2argvdata/qemuxml2argv-restore-v1.args |    1 
>  b/tests/qemuxml2argvdata/qemuxml2argv-restore-v1.xml  |   22 +++++++++
>  b/tests/qemuxml2argvdata/qemuxml2argv-restore-v2.args |    1 
>  b/tests/qemuxml2argvdata/qemuxml2argv-restore-v2.xml  |   22 +++++++++
>  src/qemu_conf.c                                       |   44 ++++++++++++++++++
>  src/qemu_conf.h                                       |   20 ++++----
>  tests/qemuxml2argvtest.c                              |   23 +++++++--
>  9 files changed, 144 insertions(+), 12 deletions(-)

Looks OK at a brief scan, and can't be worse than failing like we do
now, so +1.

Rich.

-- 
Richard Jones, Emerging Technologies, Red Hat  http://et.redhat.com/~rjones
Read my OCaml programming blog: http://camltastic.blogspot.com/
Fedora now supports 68 OCaml packages (the OPEN alternative to F#)
http://cocan.org/getting_started_with_ocaml_on_red_hat_and_fedora