Did a bit more testing. I open a connection to the hypervisor from python using: con = libvirt.open('qemu:///system') No call that I tried on con returns while a migration is in progress. I tried: listDomainsID, lookupByID, getInfo, getHostname, getType. This sort of combines with my other outstanding email, about how to use migrateSetMaxDowntime. If I can't even get a domain object for a migrating domain, how could I possibly set max downtime AFTER the migration has begun? I must be missing something crucial. Can someone please give me some wisdom? --Igor On Fri, Dec 17, 2010 at 02:06:27AM -0600, Igor Serebryany wrote:

Hmm, the behavior you get is really weird. Most of libvirt APIs are synchronous so they only return after the operation has finished. If you need to do something else while the operation is running, you need a separate connection to libvirt (opened in a separate process or thread) which you can use for manipulating with other domains or, to some extent, even with the same domain. In the migration case, you can use the second connection to monitor migration progress (virDomainGetJobInfo), cancel the migration (virDomainAbortJob), turn live migration into non-live migration (virDomainSuspend), or setting maximum downtime (virDomainMigrateSetMaxDowntime). It's quite strange, that as you say you have two python processes and virDomainMigrateSetMaxDowntime doesn't finish until the migration itself finishes. I would suggest to start with a simple setup and try with virsh migrate and virsh migrate-setmaxdowntime started from separate terminals, but in your first email, you said you can't even run virsh list while migration is running, right? So could you make sure you have debug info libvirt packages installed or in case you compile libvirt yourself that you compile with -g (should be there by default) and don't strip binaries. Then try to get into the state, when a migration is running and virsh list (or virsh migrate-setmaxdowntime) from another terminal is blocked and attach gdb to libvirtd gdb -p $(pidof libvirtd) and type "thread apply all bt" in the gdb and send us the result. I'm curious why it doesn't work for you. Jirka

Ouch, I wonder if that could be the reason... Could you just compile libvirt yourself? Personally, I wouldn't really trust such transformed package esp. considering the hacky steps you did and described in another email. Thanks, that was a good idea since according to it virsh is stuck while it tries to authenticate to libvirtd. Could you run this second virsh list with LIBVIRT_DEBUG environment variable set to 1 and attach the debug output? Also please check the virsh is stuck in the same place. Hopefully the log will tell us more. Jirka