[libvirt-users] Should domain be undefined after migration, or not?

[Daniel P. Berrange]

On Sun, Jan 19, 2014 at 10:03:36PM +0600, Brian Candler wrote:
> I have been running a lab using libvirt under Debian Wheezy (libvirt
> 0.9.12.3-1, qemu-kvm 1.1.2+dfsg-6, virt-manager 0.9.1-4). There are
> a number of machines as front-end servers and an nbd shared storage
> backend.
> 
> When I live-migrate a domain from one machine to another, normally I
> observe that afterwards the domain remains on the source host (but
> in "shutdown" state), as well as on the target host (in "running"
> state). But occasionally I have observed the domain being removed
> from the source host.
> 
> The trouble with the domain remaining on the source host is that it
> is all too easy to double-click on the shutdown domain in
> virt-manager and start it there accidentally, in addition to the
> copy on the target host - resulting in disaster. (I know this can be
> prevented using the sanlock plugin)
> 
> Furthermore, there could be stale copies of the XML lying around on
> some machines where the domain had been running at some point in the
> past.
> 
> My question is, what is the expected behaviour? Is not removing the
> domain definition from the source host a bug? Has this been changed
> in a newer version of libvirt?

For historical reasons the default is to leave the config file
present on the source machine. You can control this behaviour
though when triggering migration. There are an insane number
of possible scenarios...

   http://libvirt.org/migration.html#config


Daniel
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