Re: [libvirt] RE: Re: kvm-81: save / restore does not work - missing incoming stdio feature
On Mon, Jan 19, 2009 at 07:20:07PM -0500, Mark Wagner wrote:
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.
>
>Daniel
So are there guidelines posted somewhere for the backwards compatibility
that must be maintained ?
The code is written to work with all QEMU >= 0.8.2, which includes
basically all KVM (bugs aside). In this case we've long supported
the existing KVM migrate syntax and cannot break our existing users
of it.
If you try to support every older version of each hypervisor /
product
you will quickly have a test matrix that will make it darn near impossible
to actually release a new version of libvirt w/o a tremendously long test
cycle.
This is why we have an extensive test suite to cover generation of
command line arguments & explicitly test these kind of scenarios
where one version changes the command line syntax.
Daniel
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