[Libguestfs] Libguestfs can't launch with one of the disk images in the RHEV cluster

[Richard W.M. Jones]

On Tue, Jan 14, 2014 at 08:07:43AM +0000, Исаев Виталий Анатольевич wrote:

> [00072ms] /usr/libexec/qemu-kvm \
>     -global virtio-blk-pci.scsi=off \
>     -nodefconfig \
>     -nodefaults \
>     -nographic \
>     -drive file=/dev/mapper/1a9aa971--f81f--4ad8--932f--607034c924fc-666faa62--da73--4465--aed2--912119fcf67f,snapshot=on,if=virtio \
>     -nodefconfig \
>     -machine accel=kvm:tcg \
>     -m 500 \
>     -no-reboot \
>     -device virtio-serial \
>     -serial stdio \
>     -device sga \
>     -chardev socket,path=/tmp/libguestfs2yVhoH/guestfsd.sock,id=channel0 \
>     -device virtserialport,chardev=channel0,name=org.libguestfs.channel.0 \
>     -kernel /var/tmp/.guestfs-0/kernel.3269 \
>     -initrd /var/tmp/.guestfs-0/initrd.3269 \
>     -append 'panic=1 console=ttyS0 udevtimeout=300 no_timer_check acpi=off printk.time=1 cgroup_disable=memory selinux=0 guestfs_verbose=1 TERM=xterm ' \
>     -drive file=/var/tmp/.guestfs-0/root.3269,snapshot=on,if=virtio,cache=unsafeqemu-kvm: -drive file=/dev/mapper/1a9aa971--f81f--4ad8--932f--607034c924fc-666faa62--da73--4465--aed2--912119fcf67f,snapshot=on,if=virtio: could not open disk image /dev/mapper/1a9aa971--f81f--4ad8--932f--607034c924fc-666faa62--da73--4465--aed2--912119fcf67f: No such file or directory
> libguestfs: child_cleanup: 0x23dc5d0: child process died
> libguestfs: trace: launch = -1 (error)

libguestfs runs qemu with the command line above.  qemu tries to open
the /dev/mapper/1a9... file.  qemu reports that it cannot open that file.

Unfortunately qemu's error messages are very poor.  However there are
a few possibilities:

(a) An actual permissions issue.  Since you seem to be running this as
root, this doesn't seem to be likely, but you should check that
anyway.  Are there SELinux AVCs?

(b) qemu cannot open the backing file.  Try running:

  qemu-img info /dev/mapper/1a9...

and if it has a backing file, check that the backing file(s)
[recursively] can be opened too.

(c) Also check that the backing file paths are not relative.  If they
are you will need to run your script from the correct directory so
that the relative paths are accessible.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
virt-p2v converts physical machines to virtual machines.  Boot with a
live CD or over the network (PXE) and turn machines into KVM guests.
http://libguestfs.org/virt-v2v