= 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://deb.debian.org/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://deb.debian.org/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://deb.debian.org/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://deb.debian.org/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
[[http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=698451#10|#698451]].


== powerpc ==

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

 * Extract vmlinuz-2.4.27-001 from the [[http://www.overselfresearch.com/kb/download/qemu/kernel-2.4.27-ppc32-prep-debian_sarge_patches-preptool_patch.zip|following tarball]];
 * Download preptool from http://www.olifantasia.com/qemu/kernels/2.4.25/preptool
 * Then run prepool on the kernel image, so as to pass correct parameters to the kernel directly:
{{{
$ 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