On 09/05/2013 12:47 PM, Chris Friesen wrote: > Hi, > > If I kill a libvirt-managed kvm process with "kill -9", running "virsh > domstate --reason <name>" gives > > shut off (crashed) > > Looking at the code, that corresponds to > VIR_DOMAIN_SHUTOFF/VIR_DOMAIN_SHUTOFF_CRASHED. The comment says that > VIR_DOMAIN_SHUTOFF_CRASHED corresponds to "domain crashed". Is this > supposed to be a crash of the hypervisor, or of the guest OS? Both. Any case where a crash has transitioned the domain into a shutoff state (no qemu process exists any more), in such a way that libvirt knows that it is a crash. > > If I trigger a panic in the guest, it sits there in the panicked state > doing nothing and "virsh domstate" gives > > running (booted) Depending on what version of kernel you have and what version of qemu you are using, you can set things up so that qemu exposes '-device pvpanic' to the guest, and Linux guests can then write to that device on kernel panic, so that qemu then forwards a crash event to libvirt. (Theoretically, someone could write a windows driver so that Windows guests could also trigger the qemu event, but to date, no one has done that). With that in place, a guest panic would no longer show up as running(booted), but as crashed(panicked). But right now, since qemu 1.6 botched the implementation of '-device pvpanic', we are waiting for qemu 1.7 to stabilize the design, so there is no easy way to pass -device pvpanic on the qemu command line except using <qemu:commandline> XML extensions that take you into the realm of unsupportedness. > > So what's the point of VIR_DOMAIN_CRASHED/VIR_DOMAIN_CRASHED_PANICKED? To differentiate between the qemu panic event (the qemu process still exists) and the completely dead qemu (your kill -9 attempt), if you are using the pvpanic device. Trust me, this whole area is a big mess, that has been drawn out in several long debates on both qemu and libvirt lists, for more than a year now. -- Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org
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