Re: [libvirt] [openstack-dev] [nova] The risk of hanging when shutdown instance.

On 2015/3/31 4:36, Eric Blake wrote: > On 03/30/2015 06:08 AM, Michal Privoznik wrote: >> On 30.03.2015 11:28, zhang bo wrote: >>> On 2015/3/28 18:06, Rui Chen wrote: >>> >>>> <snip/> >>> The API virDomainShutdown's description is out of date, it's not correct. >>> In fact, virDomainShutdown would block or not, depending on its mode. If it's in mode *agent*, then it would be blocked until qemu founds that the guest actually got down. >>> Otherwise, if it's in mode *acpi*, then it would return immediately. >>> Thus, maybe further more work need to be done in Openstack. >>> >>> What's your opinions, Michal and Daniel (from libvirt.org), and Chris (from openstack.org) :) >>> >> >> Yep, the documentation could be better in that respect. I've proposed a >> patch on the libvirt upstream list: >> >> https://www.redhat.com/archives/libvir-list/2015-March/msg01533.html > I don't think a doc patch is right. If you don't pass any flags, then > it is up to the hypervisor which method it will attempt (agent or ACPI). > Yes, explicitly requesting an agent as the only method to attempt might > be justifiable as a reason to block, but the overall API contract is to > NOT block indefinitely. I think that rather than a doc patch, we need > to fix the underlying bug, and guarantee that we return after a finite > time even when the agent is involved. > So, may we get to a final decision? :) Shall we timeout in virDomainShutdown() or leave it to openstack? The 2 solutions I can see are: 1) timeout in virDomainShutdown() and virDomainReboot(). in libvirt. 2) spawn a new thread to monitor the guest's status, if it's not shutoff after dom.shutdown() for a while, call dom.destroy() to force shut it down. in openstack.