Debian-Installer: Building the installer yourself

This page explains how to manually build specific images. Alternative approaches are available:

The installer can be built like any other package (using for example dpkg-buildpackage or debuild) although this is probably not what you want, as doing this will generate images you won't need for testing changes, and thus takes much longer.
Take advantage of the fact that udeb repositories on salsa should be configured to use branch2repo, which means that if you fork such a repository and make modifications, the CI pipeline will include a mini-ISO job, that creates a mini-ISO for you that incorporates your changes. This allows you to test that your changes before you create an MR. It is also possible to launch automated tests using openQA

First of all, debian-installer images should only be built in an environment that matches the version of the installer you want to build, so:

if you want to build the installer for development purposes, your system needs to be running unstable, or you need to create a chroot environment that has unstable;
if you want to build D-I for a specific Debian release, e.g. for the current stable release, your system needs to either be running the current Debian stable release, or you need to create a chroot that has the stable release.

Note: Don't forget to mount /proc inside chroot. mkfs.vfat is failing if you are running a chroot in sid, so it is better to have a full lenny installation (you could use Virtual Box or qemu, roughly the same space as a chroot)

If you get this wrong, build errors or non-working images are almost guaranteed! It is sometimes possible to smuggle with testing and unstable, but don't expect any support from the D-I team if you do.

This same procedure can also be followed to build the installer from testing, using udebs from testing. But you should be aware that there are periods during which it is very likely that builds from testing are broken, especially: (1) the period after a new Debian stable release and before the first alpha release of D-I for the next Debian release and (2) when a new release of D-I is being prepared. Building the installer from testing is only really advisable when there is a Release Candidate (RC) release of debian-installer in testing.

$/!\$ If you build the installer for release purposes, make sure your build environment is "clean", i.e. that it is up-to-date and that you don't have any weird (versions of) packages installed from external repositories. If your system is not clean, use for example pbuilder or create a chroot environment.

Here are the steps to build debian-installer and download required udebs.

Get the source

See CheckOut.

Preparing the build system

Change to the directory installer/ under your TOP directory.
Read build/README
Install the build-dependencies on the host system (or in the chroot):
```
# apt build-dep debian-installer
```

Verify that the build dependencies are all met using dpkg-checkbuilddeps. You may still see something like:

$ dpkg-checkbuilddeps
dpkg-checkbuilddeps: Unmet build dependencies: grep-dctrl debiandoc-sgml glibc-pic libparted1.6-13 libslang2-pic libnewt-pic libdiscover1-pic libbogl-dev genext2fs (>= 1.3-7.1) mklibs (>= 0.1.15) mkisofs dosfstools syslinux (>= 2.11-0.1) tofrodos bf-utf-source upx-ucl-beta (>= 1:1.91+0.20030910cvs-2)

which means some build dependencies are still missing. Correct this by installing the missing packages, for example:

# aptitude install -R grep-dctrl debiandoc-sgml [...]

repeat the check until dpkg-checkbuilddeps no longer reports any missing dependencies.

Check that the variables DEBIAN_RELEASE and USE_UDEBS_FROM in the file build/config/common are set correctly:
- if you are building the installer for development purposes (from Git HEAD), no changes should be needed;
- if you are building the installer for stable or oldstable, the variables should already be set to the codename of that Debian release; if not you need to change them;
- if you are building the installer for testing it is likely you will need to change at least the variable USE_UDEBS_FROM to the codename for testing.

Building an image

Change directory to the directory installer/build/.
Run make to get a list of available targets.
Build an image using one of the "build" targets (build_netboot, all_build, etc).
```
$ make reallyclean
$ fakeroot make build_netboot
```

Because your build environment is for the same Debian release as the version of debian-installer you want to build, the build system should automatically generate a correct sources.list.udeb file based on your /etc/apt/sources.list. However, in some cases it may be necessary to create a sources.list.udeb.local. In some cases you have to explicitly provide main/debian-installer section in the sources.list file of your chroot or local installation.

Look in dest/ for the completed images.
Look in dest/MANIFEST.udebs for the udebs associated with this image.

Adding a udeb or files to the built image

The list of packages added to the netboot image is in installer/build/pkg-lists/netboot/yourarch.cfg , you can try add the desired package there.

In order to just add a few files, you can create your own udeb package:

Create a control file containing:

Package: mypackage
Files: /my/file/on/my/hard/drive /where/to/put/it/in/installer
 /my/other/file /another/place/in/installer

run equivs-build control , that will create mypackage_1.0_all.deb, which you can rename to mypackage.udeb, and put it into installer/build/localudebs . You can then add mypackage in installer/build/pkg-lists/netboot/yourarch.cfg

Questions

How does one build an image which also contains a repository, like the netinst images contain?
- A: This is normally done using debian-cd; see also DebianInstaller/Modify
If I'm not able to rebuild Debian-Installer from source, what should I do?
- A: Persist. Most likely you are already subscribed mailinglist debian-boot where development of d-i is discussed. Explain in an e-mail to that ML where you are stuck.

CategoryDebianInstaller