Re: [libvirt] [PATCH] bhyve: implement domainShutdown

On Tue, Mar 29, 2016 at 10:52:09AM -0400, Laine Stump wrote: > On 03/29/2016 08:24 AM, Daniel P. Berrange wrote: > >On Mon, Mar 28, 2016 at 10:27:18AM +0300, Roman Bogorodskiy wrote: > >>Bhyve supports ACPI shutdown by issuing SIGTERM signal to the bhyve > >>process. Add the bhyveDomainShutdown() function and > >>virBhyveProcessShutdown() helper function that just sends SIGTERM to > >>VM's bhyve process. If a guest supports ACPI shutdown then process > >>will be terminated and this event will be noticed by the bhyve monitor > >>code that will handle setting proper status and clean up VM's resources. > >> > >>Also, remove a warning in domainDestroy in case if > >>virProcessKillPainfully() returns 1, meaning that it killed process > >>using SIGKILL. This behavior should be expected when using 'destroy'. > >Hmm, so destroy is supposed to be equivalent to physically removing > >the power plug. The existing code is calling virProcessShutdownPainfully > >which starts by sending SIGTERM and then switches to SIGKILL. So this > >means that your virDomainDestroy implementation is mistakenly trying todo > >a graceful shutdown initially and then switching to hard shutdown after a > >bit of a delay. > > For context - the qemu driver does this for destroy as well. I think at > least one of the reasons is to allow the qemu process to flush the buffers > for the disk image files. I recall this was causing some amount of pain for > ovirt (or maybe someone else, I forget) Yep it is different in QEMU - SIGTERM doesn't trigger any guest OS ACPI event with QEMU - it merely lets QEMU gracefully close the block layer functions and flush I/O. > >Has bhyve always used SIGTERM to trigger ACPI shutdown, or is this a > >recent addition ? I would tend to suggest we need to go straight to > >SIGKILL for virDomainDestroy to avoid doing ACPI shutdown when we don't > >want it. > > > >It is kind of a shame they used SIGTERM for triggering ACPI imho but > >oh well. > > Yes, it means there is no way to implement a "clean power off" (which would > give bhyve the chance to clean up some critical things before pulling the > plug). Yeah, exactly, it is desirable to be able to do a immediate forced shutdown of guest OS while still letting the host process exit cleanly.

Regards, Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :|