qemu-nbd -P option not working - error while reading

[Randy Barlow]

Binary package hint: qemu-kvm

I am unable to use qemu-nbd as an nbd-server in Lucid. In Karmic, the following command works, but not in Lucid:

$ qemu-nbd -n -b localhost -p 2000 -P 1 base.qcow2
qemu-nbd: error while reading

Where base.qcow2 is just a regular qcow image. The image is definitely valid, as I can run it with kvm just fine. Unfortunately, there doesn't seem to be any useful information in the kernel log about this, and there isn't any further information that I know how to get that would be useful.

ProblemType: Bug
Architecture: amd64
Date: Thu Mar 25 11:40:59 2010
DistroRelease: Ubuntu 10.04
EcryptfsInUse: Yes
InstallationMedia: Ubuntu 9.10 "Karmic Koala" - Release amd64 (20091027)
KvmCmdLine: Error: command ['ps', '-C', 'kvm', '-F'] failed with exit code 1: UID PID PPID C SZ RSS PSR STIME TTY TIME CMD
MachineType: Dell Inc. Latitude E6500
NonfreeKernelModules: wl
Package: qemu-kvm 0.12.3+noroms-0ubuntu2
PccardctlIdent:
 Socket 0:
   no product info available
PccardctlStatus:
 Socket 0:
   no card
ProcCmdLine: BOOT_IMAGE=/boot/vmlinuz-2.6.32-17-generic root=UUID=3c7abe9e-d3a4-4123-b57f-2a41b13a3fcd ro quiet splash apparmor=0
ProcEnviron:
 LANG=en_US.utf8
 SHELL=/bin/bash
ProcVersionSignature: Ubuntu 2.6.32-17.26-generic 2.6.32.10+drm33.1
SourcePackage: qemu-kvm
Uname: Linux 2.6.32-17-generic x86_64
dmi.bios.date: 09/17/2009
dmi.bios.vendor: Dell Inc.
dmi.bios.version: A16
dmi.board.name: 0W612R
dmi.board.vendor: Dell Inc.
dmi.chassis.type: 8
dmi.chassis.vendor: Dell Inc.
dmi.modalias: dmi:bvnDellInc.:bvrA16:bd09/17/2009:svnDellInc.:pnLatitudeE6500:pvr:rvnDellInc.:rn0W612R:rvr:cvnDellInc.:ct8:cvr:
dmi.product.name: Latitude E6500
dmi.sys.vendor: Dell Inc.

[Torsten Spindler (tspindler)]

Does it work without the -P 1 option?

[Randy Barlow (rbarlow)]

It does seem to work without the -P 1 option. Unfortunately, the rest of the system I've built around this doesn't work if I start the server that way, but perhaps I can work around. So perhaps the partition option is what is broken for Lucid?

[Serge Hallyn (serge-hallyn)]

Hi,

are you still having this problem?

I tried to reproduce this as follows:

1. Created a .qcow 2 file using:

vmbuilder kvm ubuntu --suite lucid --flavour server --mirror http://localhost:3142/us.archive.ubuntu.com/ubuntu/

2. ran qemu-nbd as:

qemu-nbd -n -b localhost -p 2000 ubuntu-kvm/tmpGVbB1c.qcow2 -P 1

3. ran nbd-client as:

nbd-client localhost 2000 /dev/nbd1

4. mounted the fs as:

mount /dev/nbd1 /mnt

The fs was successfully mounted, i.e. 'ls /mnt' showed the contents.

5. umounted and disconnected using

umount /mnt
nbd-client -d /dev/nbd1

[Launchpad Janitor (janitor)]

[Expired for qemu-kvm (Ubuntu) because there has been no activity for 60 days.]