Re: [libvirt] [PATCH V6] support offline migration

On 09/10/2012 08:20 PM, liguang wrote: > original migration did not aware of offline case > so, add code to support offline migration quietly > (did not disturb original migration) by pass > VIR_MIGRATE_OFFLINE flag to migration APIs if the > domain is really inactive, and > migration process will not puzzeled by domain s/puzzeled/puzzled/ > offline and exit unexpectly. s/unexpectly/unexpectedly/ > these changes did not take care of disk images the > domain required, for disk images could be transfered s/transfered/transferred/ > by other APIs as suggested. > so, the migration result is just make domain > definition alive at target side. > > Signed-off-by: liguang <lig.fnst(a)cn.fujitsu.com&gt; > --- > include/libvirt/libvirt.h.in | 1 + > src/qemu/qemu_driver.c | 8 ++++++ > src/qemu/qemu_migration.c | 55 ++++++++++++++++++++++++++++++++++++----- > src/qemu/qemu_migration.h | 3 +- > tools/virsh-domain.c | 6 ++++ > 5 files changed, 65 insertions(+), 8 deletions(-) > > diff --git a/include/libvirt/libvirt.h.in b/include/libvirt/libvirt.h.in > index cfe5047..77df2ab 100644 > --- a/include/libvirt/libvirt.h.in > +++ b/include/libvirt/libvirt.h.in > @@ -995,6 +995,7 @@ typedef enum { > * whole migration process; this will be used automatically > * when supported */ > VIR_MIGRATE_UNSAFE = (1 << 9), /* force migration even if it is considered unsafe */ > + VIR_MIGRATE_OFFLINE = (1 << 10), /* offline migrate */ Do we really need a new user-visible flag, or can we make this work automatically without having to involve the user? On the other hand, what happens if we do keep this as a user-visible flag? Should 'virsh migrate --offline' silently ignore the flag if the guest is online, or should it error out stating that the guest is running and not offline? Also, I think we NEED to error out if the guest is offline but the --persistent flag is not set; that is, an offline migration only makes sense if the persistent flag has been requested, but I think that 'virsh migrate --persistent' should automatically be smart enough to do an offline migration.

You either need to take care of migrating storage if the user does 'virsh migrate [whatever-we-decide-for-offline] --copy-storage-*', or else explicitly reject attempts to migrate storage in parallel with an offline migration.