libvirt fails to start VirtualMachines I've created several kvm based machines with the 'trusty' designation using virtual machine manager. They have operated well over the last 4 days without issue. I did an apt-get upgrade, and qemu was in the list of updates. After upgrading, I am unable to start any of the provisioned virtual machines with the following error output virsh # start node2 error: Failed to start domain node2 error: internal error: process exited while connecting to monitor: qemu-system-x86_64: -machine trusty,accel=kvm,usb=off: Unsupported machine type Use -machine help to list supported machines! virsh # start node3 error: Failed to start domain node3 error: internal error: process exited while connecting to monitor: qemu-system-x86_64: -machine trusty,accel=kvm,usb=off: Unsupported machine type Use -machine help to list supported machines! $ dpkg -l | grep kvm ii qemu-kvm 2.0.0~rc1+dfsg-0ubuntu3 amd64 QEMU Full virtualization on x86 hardware (transitional package) Log snippet from vm 'media' that was verified working, and fails to start after the upgrade. LC_ALL=C PATH=/usr/local/sbin:/usr/local/bin:/usr/bin:/usr/sbin:/sbin:/bin QEMU_AUDIO_DRV=none /usr/bin/kvm-spice -name media -S -machine trusty,accel=kvm,usb=off -m 1548 -realtime mlock=off -smp 1,sockets=1,cores=1,threads=1 -uuid 60b20f7b-6d20-bcb3-f4fc-808a9b2fe0d0 -no-user-config -nodefaults -chardev socket,id=charmonitor,path=/var/lib/libvirt/qemu/media.monitor,server,nowait -mon chardev=charmonitor,id=monitor,mode=control -rtc base=utc -no-shutdown -boot menu=off,strict=on -device piix3-usb-uhci,id=usb,bus=pci.0,addr=0x1.0x2 -drive file=/var/lib/libvirt/images/media.img,if=none,id=drive-virtio-disk0,format=raw -device virtio-blk-pci,scsi=off,bus=pci.0,addr=0x4,drive=drive-virtio-disk0,id=virtio-disk0,bootindex=1 -drive file=/home/charles/iso/ubuntu-desktop-12.04.4-amd64.iso,if=none,id=drive-ide0-1-0,readonly=on,format=raw -device ide-cd,bus=ide.1,unit=0,drive=drive-ide0-1-0,id=ide0-1-0 -netdev tap,fd=24,id=hostnet0,vhost=on,vhostfd=26 -device virtio-net-pci,netdev=hostnet0,id=net0,mac=52:54:00:a0:69:d9,bus=pci.0,addr=0x3 -chardev pty,id=charserial0 -device isa-serial,chardev=charserial0,id=serial0 -vnc 127.0.0.1:1 -device cirrus-vga,id=video0,bus=pci.0,addr=0x2 -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x5 char device redirected to /dev/pts/13 (label charserial0) qemu: terminating on signal 15 from pid 31688 2014-04-10 03:36:54.593+0000: shutting down 2014-04-10 03:59:25.487+0000: starting up LC_ALL=C PATH=/usr/local/sbin:/usr/local/bin:/usr/bin:/usr/sbin:/sbin:/bin QEMU_AUDIO_DRV=none /usr/bin/kvm-spice -name media -S -machine trusty,accel=kvm,usb=off -m 1548 -realtime mlock=off -smp 1,sockets=1,cores=1,threads=1 -uuid 60b20f7b-6d20-bcb3-f4fc-808a9b2fe0d0 -no-user-config -nodefaults -chardev socket,id=charmonitor,path=/var/lib/libvirt/qemu/media.monitor,server,nowait -mon chardev=charmonitor,id=monitor,mode=control -rtc base=utc -no-shutdown -boot menu=off,strict=on -device piix3-usb-uhci,id=usb,bus=pci.0,addr=0x1.0x2 -drive file=/var/lib/libvirt/images/media.img,if=none,id=drive-virtio-disk0,format=raw -device virtio-blk-pci,scsi=off,bus=pci.0,addr=0x4,drive=drive-virtio-disk0,id=virtio-disk0,bootindex=1 -drive file=/home/charles/iso/ubuntu-desktop-12.04.4-amd64.iso,if=none,id=drive-ide0-1-0,readonly=on,format=raw -device ide-cd,bus=ide.1,unit=0,drive=drive-ide0-1-0,id=ide0-1-0 -netdev tap,fd=24,id=hostnet0,vhost=on,vhostfd=25 -device virtio-net-pci,netdev=hostnet0,id=net0,mac=52:54:00:a0:69:d9,bus=pci.0,addr=0x3 -chardev pty,id=charserial0 -device isa-serial,chardev=charserial0,id=serial0 -vnc 127.0.0.1:0 -device cirrus-vga,id=video0,bus=pci.0,addr=0x2 -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x5 qemu-system-x86_64: -machine trusty,accel=kvm,usb=off: Unsupported machine type Use -machine help to list supported machines! 2014-04-10 03:59:25.696+0000: shutting down After some additional investigating it looks like the XML format for the trusty machine has changed. I created a new VM and got it to boot off my MAAS cluster, The immediate change I see is: new: hvm old: hvm None of the old XML machines were updated with this new machine flag. Thanks for reporting this bug. We briefly had a 'trusty' machine type, with a corresponding libvirt patch to handle it. When we renamed the trusty machine type we dropped the libvirt patch to handle it. We should either re-introduce the libvirt patch to handle the trusty machine type for those who have stale VM definitions, or mention this in the release notes. In either case we should keep this bug open to guide others who run into this problem. This has just happened to me. For some reason, all my machines had machine='pc-i440fx-wily'. After an update in yakkety, they stopped working. $ qemu-system-x86_64 -enable-kvm -machine help | grep wily So I updated the machine xml to a supported machine as Charles suggested, and they work again. Here's the note for my future self about how to do the update: $ virsh dumpxml $machine-name > /tmp/machine.xml Edit the xml. $ virsh define /tmp/machine.xml Machine type changes may be related to: https://bugs.launchpad.net/ubuntu/+source/qemu/+bug/1626070 There's a PPA in the bug with a fix for at least the wily machine type. On Thu, Sep 22, 2016 at 6:05 PM, Leo Arias