[libvirt] [PATCH v9] support offline migration

[Daniel P. Berrange]

On Tue, Sep 25, 2012 at 03:45:24PM +0800, liguang wrote:
> original migration did not aware of offline case,
> so, try to support offline migration quietly
> (did not disturb original migration) by pass
> VIR_MIGRATE_OFFLINE flag to migration APIs if only
> the domain is really inactive, and
> migration process will not puzzled by domain
> offline and exit unexpectedly.
> these changes did not take care of disk images the
> domain required, for them could be transferred by
> other APIs as suggested, then VIR_MIGRATE_OFFLINE
> should not combined with VIR_MIGRATE_NON_SHARED_*.
> so, this migration result is just make domain
> definition alive at target side.
> 
> Signed-off-by: liguang <lig.fnst at cn.fujitsu.com>
> ---
>  include/libvirt/libvirt.h.in |    1 +
>  src/qemu/qemu_driver.c       |   15 ++++++++++++
>  src/qemu/qemu_migration.c    |   53 ++++++++++++++++++++++++++++++++++++-----
>  src/qemu/qemu_migration.h    |    3 +-
>  tools/virsh-domain.c         |    6 ++++
>  5 files changed, 70 insertions(+), 8 deletions(-)

In my testing this patch is still badly broken, apparently no different
than the previous version I tested

I have 2 hosts, avocado & mustard and stopped guest vm1. I try to
migrate the VM from avocado to mustard thus:

 # ./tools/virsh -c qemu+ssh://root@avocado/system migrate --undefinesource --offline vm1 qemu+ssh://root@mustard/system

This should *not* even run because I did not pass the --persistent flag,
but it does in fact complete. I creates a guest 'vm1' on the target host,
but does not write out any config. This is a completely bogus scenario.
If a guest has no config, it is transient and thus must not exist if it
is shutoff, but your patch is resulting in a transient, shutoff guest.

If I set the '--persistent' flag, there is no diffrence in behaviour. We
still get a transient shutoff guest on the target.

Also the '--undefinesource' flag appeared to have no effect at all. The
guest still exists on the source, both in libvirtd & on disk.


Daniel
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