qemubuilder

This page is README.Debian of qemubuilder, a pbuilder implementation using qemu. See also cowbuilder.

Usage

pbuilderrc-arch.config:

KERNEL_IMAGE=/boot/vmlinuz-2.6.21-1-686
INITRD=/boot/initrd.img-2.6.21-1-686
MIRRORSITE=http://ftp.cz.debian.org/debian
ARCH=i386
BASEPATH=/var/cache/pbuilder/base-i386.qemu
MEMORY_MEGS=64

and adjust the KERNEL_IMAGE and INITRD paths, so that they point to the kernel and initrd that you want to use in qemu (so obviously, for ARCH=i386, use i386 kernel, for amd64, use amd64 kernel, etc.). Adjust the MIRRORSITE to your favourite Debian mirror.

Create the base image:

$ sudo qemubuilder --create --configfile pbuilder-arch.config
[...]
Setting up g++ (4:4.2.1-6) ...
Setting up dpkg-dev (1.14.6) ...
Setting up build-essential (11.3) ...

 -> received termination signal with exit-code 0, killing child process (qemu)
  -> killed (qemu)
 -> child process terminated with status: f

This is a correct behavior and the qemu image /var/cache/pbuilder/base-i386.qemu was successfully created (it will have 3.1GB). If this step doesn't work, read the logs first, then if you can't figure out what's wrong, please report a bug.

Compile a package:

$ sudo qemubuilder --configfile pbuilder-arch.config --build something.dsc
[...]
 dpkg-genchanges
dpkg-genchanges: including full source code in upload
dpkg-buildpackage: full upload; Debian-native package (full source is included)

  -> received termination signal with exit-code 0, killing child process (qemu)
   -> killed (qemu)
  -> child process terminated with status: f
 -> running post-run process
running host command: cp -p "/var/cache/pbuilder/build//qemu.16459"/*_* "/var/cache/pbuilder/result/" 2>/dev/null || true
 -> clean up COW device files

and the source and binary package will be in /var/cache/pbuilder/result/.

See also man qemubuilder, man pbuilder and /usr/share/doc/pbuilder/pbuilder-doc.html.

Architecture specific information

To run qemubuilder you need a kernel image, and optionally initrd.

To get qemubuilder working, qemu support for that target architecture, the kernel image (and optionally initrd image) for the target architecture, and a way to invoke the kernel from the command-line using -kernel command-line option is required. Support for specifying disk devices through -hda and -hdb is required for operation.

You might have some luck finding some of the kernels from http://people.debian.org/~aurel32/qemu/ Ideally you should be able to find the kernels from Debian archive, but we're not there yet.

i386

Files from Debian kernel package (linux-image-xxx) should work.

An example of a working configuration as of September 7, 2007 - use sid, run on i386, emulate i386:

$ sudo apt-get install linux-image-2.6.22-2-686
$ cat pbuilderrc-i386.config 
KERNEL_IMAGE=/boot/vmlinuz-2.6.22-2-686
INITRD=/boot/initrd.img-2.6.22-2-686
MIRRORSITE=http://ftp.cz.debian.org/debian
ARCH=i386
BASEPATH=/var/cache/pbuilder/base-i386.qemu
MEMORY_MEGS=64
$ sudo qemubuilder --configfile pbuilderrc-i386.config --create
[...]

and a working qemu image base-i386.qemu is created in /var/cache/pbuilder/.

use sid, run on amd64, emulate i386:

# on i386 machine do:
$ scp /boot/vmlinuz-2.6.22-2-686 /boot/initrd.img-2.6.22-2-686 some.amd64.computer.cz:debian/
# on the amd64 machine, in the "debian" directory
$ cat pbuilderrc-i386.config 
KERNEL_IMAGE=vmlinuz-2.6.22-2-686
INITRD=initrd.img-2.6.22-2-686
MIRRORSITE=http://ftp.cz.debian.org/debian
ARCH=i386
BASEPATH=/var/cache/pbuilder/base-i386.qemu
MEMORY_MEGS=64
$ sudo qemubuilder --configfile pbuilderrc-i386.config --create
[...]

and a working qemu image base-i386.qemu is created in /var/cache/pbuilder/.

amd64

Files from Debian kernel package (linux-image-xxx) should work.

An example of a working configuration as of September 7, 2007 - use sid, run on i386, emulate amd64:

$ sudo apt-get install linux-image-2.6.22-2-amd64
$ cat pbuilderrc-amd64.config
KERNEL_IMAGE=/boot/vmlinuz-2.6.22-2-amd64
INITRD=/boot/initrd.img-2.6.22-2-amd64
MIRRORSITE=http://cdn.debian.net/debian
ARCH=amd64
BASEPATH=/home/ondra/debian/base-amd64.qemu
MEMORY_MEGS=64
$ sudo qemubuilder --configfile pbuilderrc-amd64.config --create
[...]

and a working qemu image base-amd64.qemu is created in /home/ondra/debian/.

I found that MEMORY_MEGS=64 was too small. It seemed to work much better for me with MEMORY_MEGS=512 [DavidBremner]

arm

kernel for versatile architecture is available from Debian archive: http://cdn.debian.net/debian/pool/main/l/linux-latest-2.6/ for example, linux-image-2.6.26-1-versatile_2.6.26-12_armel.deb This kernel requires initrd, and ext3 and ethernet driver module is not built-in.

Currently you cannot use this kernel. But yosh@d.o came to rescue with a self-prepared kernel he is offering to all on http://yoush.homelinux.org:8079/tech/setting-up-armel-qemubuilder accompanied with a nice description of how to set it up and about what exactly he had done.

mips

For etch, there was qemu architecture, for lenny it's malta.

Get the kernel and initrd from http://cdn.debian.net/debian/pool/main/l/linux-latest-2.6/ for malta architecture, is this too modularized too?

mipsel

For etch, there was qemu architecture, for lenny and higher it's malta. "initrd" is not needed for "mipsel".

Sample config file "qemubuilderrc-mipsel"

ARCHITECTURE=mipsel
KERNEL_IMAGE=/var/cache/pbuilder/vmlinux-3.10-2-4kc-malta
BASEPATH=/var/cache/pbuilder/mipsel-unstable.raw
MIRRORSITE=http://http.debian.net/debian
DISTRIBUTION=sid
MEMORY_MEGS=256
#BUILDPLACE=/var/cache/pbuilder/build
#DEBBUILDOPTS=" -B"
AUTO_DEBSIGN=yes
BUILDRESULT=.
PKGNAME_LOGFILE=yes

Getting kernel image file

  1. Open http://packages.debian.org/sid/linux-image-4kc-malta

  2. click on "dep: linux-image-3.10-2-4kc-malta".
  3. click "mipsel" link in download section.
  4. choose mirror to download from.

Effectively package with kernel image can be downloaded with following sample command:

wget 'http://ftp.iinet.net.au/debian/debian/pool/main/l/linux/linux-image-3.10-2-4kc-malta_3.10.7-1_mipsel.deb'

Using mc copy boot/vmlinux-3.10-2-4kc-malta to KERNEL_IMAGE location. Alternatively vmlinux file can be extracted using the following commands

dpkg -X linux-image-3.10-2-4kc-malta_3.10.7-1_mipsel.deb .

or

ar -vx linux-image-3.10-2-4kc-malta_3.10.7-1_mipsel.deb
tar -xf data.tar.xz --wildcards --no-anchored 'boot/vmlinu*'

Create image file using

sudo qemubuilder --config /var/cache/pbuilder/qemubuilderrc-mipsel --create

If qemubuilder mounts rootfs as read-only then use workaround from #698451.

powerpc

Running fine for etch, with some quirks. Solution pending for sid. 440555

$ preptool -s"ide0=0x1f0,0x3f6,13 ide1=0x170,0x376,13 netdev=9,0x300,eth0 console=ttyS0 root=/dev/hda init=/pbuilder-run ro" vmlinuz-2.4.27.001

You're done. Package successfully build as of 15 of september 2007.

sparc

requires openbios.

found it from: http://fly.srk.fer.hr/~jelly/qemu/openbios-builtin.elf

http://mirror/debian/dists/sid/main/installer-sparc/20070308/images/combined/2.6/mini.iso

Does not support loading kernel through -kernel ?

other architecture

support needs to be added. Please mail Junichi Uekawa with information on a kernel configuration that works.

troubleshooting

kernel panic!

The last log message may say kernel panic, but that's the symptom, not the problem. Look for the messages above it. Trying out different kernel versions may help sometimes.

Location of README.Debian

canonical version is available at http://wiki.debian.org/qemubuilder the file in Debian package is updated from the contents from time to time by running debian/rules debian/qemubuilder.README.Debian