Public bug reported: Binary package hint: libvirt-bin
I can reproduce that trying to use bus='virtio' for virtual disks in the definition of a libvirt domain makes virtual disks thus defined disappear in the eyes of KVM/QEMU. This leads to error messages like the following when booting, as well as disappearance of all partitions on that virtual disk, except for the root partition (that means especially that no swap space will be enabled): One or more of the mounts listed in /etc/fstab cannot yet be mounted: (ESC for recovery shell) swap: waiting for /dev/sda2 /opt: waiting for /dev/sda3 A screenshot is available here: https://daff.pseudoterminal.org/misc/mountfailed.png It also appears, just after starting the guest, that QEMU doesn't even recognize that there are hard disk drives present, it only sees the DVD drive. See the following screenshots for comparison. bus='ide' in virtual disk domain definition: https://daff.pseudoterminal.org/misc/bus_ide.png bus='virtio' in virtual disk domain definition: https://daff.pseudoterminal.org/misc/bus_virtio.png The result is that only the root partition, probably because of initramfs/initrd and GRUB magic, will be available to the guest when using virtio, and only when no partitions other than a swap partition have been defined during setup or installation of the guest. When only a swap partition is present the boot process succeeds but still complains that it is waiting for the swap partition to become available. When there are any other partitions the boot process just hangs with the error message described above. Background: I like to take advantage of the paravirtualized IO drivers offered for KVM-based guests. Using "virtio" as bus for block devices or model type for network interfaces in the right places in a libvirt domain definition enables those drivers. To facilitate and automate this when creating guests I edited the libvirt template for vmbuilder to automatically use virtio. Notice the target line: #for $disk in $disks <disk type='file' device='disk'> <source file='$disk.filename' /> <target dev='vd$disk.devletters()' bus='virtio' /> </disk> #end for Now for creating a guest using vmbuilder, as per the Ubuntu Server Guide: # vmbuilder kvm ubuntu --dest=/storage/vms/foo -m 2048 --rootsize=4000 --optsize=4000 --hostname=foo --suite=karmic --bridge=br0 --overwrite --libvirt=qemu:///system --flavour=virtual --arch=amd64 --mirror=http://host:9999/ubuntu Here a root and an /opt partition are defined, both 4GB in size. Swap is defined automatically and defaults to 1GB. This works fine and results in the attached foo.xml libvirt domain definition. In particular the disk definition looks like this (again, notice the target line): <disk type='file' device='disk'> <source file='/storage/vms/foo/disk0.qcow2'/> <target dev='vda' bus='virtio'/> </disk> This is what the libvirt and KVM documentation pages suggest. After starting this domain the results are as described above, i.e. either a hanging boot process or a missing swap partition. When changing the target bus definition to bus='ide' everything works correctly. The domain boots as expected and contains all partitions defined during setup. This has been completely reproducible for me and I can switch between a working guest domain and a non-working by changing bus='virtio' to bus='ide' in the domain definition. This is on a Ubuntu Server Edition installation. I have no idea if this is a libvirt problem or a problem with KVM or QEMU or something else entirely. More information follows and please also see the attached files. If there is anything else I can provide please tell me. lsb_release -rd: Description: Ubuntu 9.10 Release: 9.10 apt-cache policy libvirt-bin libvirt-bin: Installed: 0.7.0-1ubuntu13.1 Candidate: 0.7.0-1ubuntu13.1 Version table: *** 0.7.0-1ubuntu13.1 0 500 http://at.archive.ubuntu.com karmic-updates/main Packages 100 /var/lib/dpkg/status 0.7.0-1ubuntu13 0 500 http://at.archive.ubuntu.com karmic/main Packages uname -a: Linux dhcp155 2.6.31-17-server #54-Ubuntu SMP Thu Dec 10 18:06:56 UTC 2009 x86_64 GNU/Linux ** Affects: libvirt (Ubuntu) Importance: Undecided Status: New -- Using virtio for block devices makes disks and partitions disappear in KVM/QEMU (using vmbuilder and libvirt) https://bugs.launchpad.net/bugs/517067 You received this bug notification because you are a member of Ubuntu Server Team, which is subscribed to libvirt in ubuntu. -- Ubuntu-server-bugs mailing list Ubuntu-server-bugs@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-server-bugs
