Translation(s): none


What is sbuild

What is sbuild:

The alternative to sbuild are

This main part of this page is intended as a short guide to sbuild. It documents how to set up sbuild and build packages with it. The later parts of the page document optional enhancements to the simple setup described in the first section.

Setup

We assume you are running at least Debian 11 bullseye (testing) using a type=directory chroot.

Automatic setup using sbuild-debian-developer-setup

sbuild provides the package sbuild-debian-developer-setup which helps you setup an sbuild environment easily, if you're interested, make sure to take a look at the manpage at https://manpages.debian.org/unstable/sbuild/sbuild-debian-developer-setup.1

Manual setup of sbuild

This ~/.sbuildrc sets up sbuild for the modern source only upload practice of Debian (SourceOnlyUpload) building for Debian unstable and to run all expected post-build tests.

   1 sudo apt-get install sbuild schroot debootstrap apt-cacher-ng devscripts
   2 sudo tee $HOME/.sbuildrc << EOF
   3 ##############################################################################
   4 # PACKAGE BUILD RELATED (source-only-upload as default)
   5 ##############################################################################
   6 # -d
   7 $distribution = 'unstable';
   8 # -A
   9 $build_arch_all = 1;
  10 # -s
  11 $build_source = 1;
  12 # --source-only-changes
  13 $source_only_changes = 1;
  14 # -v
  15 $verbose = 1;
  16 # parallel build
  17 $ENV{'DEB_BUILD_OPTIONS'} = 'parallel=5';
  18 ##############################################################################
  19 # POST-BUILD RELATED (turn off functionality by setting variables to 0)
  20 ##############################################################################
  21 $run_lintian = 1;
  22 $lintian_opts = ['-i', '-I'];
  23 $run_piuparts = 1;
  24 $piuparts_opts = ['--schroot', 'unstable-amd64-sbuild', '--no-eatmydata'];
  25 $run_autopkgtest = 1;
  26 $autopkgtest_root_args = '';
  27 $autopkgtest_opts = [ '--', 'schroot', '%r-%a-sbuild' ];
  28 
  29 ##############################################################################
  30 # PERL MAGIC
  31 ##############################################################################
  32 1;
  33 EOF
  34 sudo sbuild-adduser $LOGNAME
  35 sudo ln -sf ~$LOGNAME/.sbuild /root/.sbuild

... *logout* and *re-login* or use newgrp sbuild in your current shell

   1 sudo sbuild-createchroot --include=eatmydata,ccache unstable /srv/chroot/unstable-amd64-sbuild http://127.0.0.1:3142/cdn-fastly.deb.debian.org/debian

Now for a brief explanation on what these commands do.

  1. Install sbuild and other useful packages onto the system.
  2. Create the sbuild template configuration to your home folder. (This example is setting up sbuild for personal use, instead of as part of a build server.)
    1. This setting allows you to avoid long commandline options and run all post-build tests.
    2. Adjust parallel=5 to match your system resources.

    3. Setting the $run_lintian variable to 0 instead will disable running of lintian.

    4. Setting the $run_piuparts variable to 0 instead will disable running piuparts.

      1. '--no-eatmydata' for piuparts is needed when you configure schroot with "command-prefix=eatmydata" in /etc/schroot/chroot.d/unstable-amd64-sbuild-*.

    5. Setting the $run_autopkgtest variable to 0 instead will disable running autopkgtest.

    6. See the sbuild.conf manpage for more options.

  3. Update the active user group set to include sbuild.
    1. This will add your username so that it may use the sbuild command. Additional users may be added by running sudo sbuild-adduser USER1 USER2 .... sbuild-adduser will prompt you to copy the template sbuild configuration in /usr/share/doc/sbuild/examples/example.sbuildrc to each user's ~/.sbuildrc, to be used as their user sbuild configuration. You can customize sbuild settings here, but you usually won't need to customize anything. This should be done once per user.

  4. Use sbuild-createchroot to create a chroot used by sbuild meant for building packages targeting Debian unstable main and configured to be compatible with apt-cacher-ng. (See AptCacherNg )

    • The chroot is saved in /srv/chroot/unstable-amd64-sbuild. It installs the packages ccache and eatmydata in the chroot in case you want to use some of the enhancements detailed below. The apt repository used is the mirror service http://deb.debian.org/debian through apt-cacher-ng which will choose a suitable local mirror automatically. This can be changed to use a URL for a different mirror of the Debian archive. You can run this command once per distribution you want, and pass # --arch=i386 to create a chroot for a different architecture (the default is your host architecture).

      Each post build package test feature can be turned off by changing the corresponding variable to 0 .

      The command given above creates a type=directory chroot. If you are short of disc space, you can instead use the following command to create a chroot stored in a tarball at /srv/chroot/unstable-amd64-sbuild.tar.gz. This is not recommended unless you really can't spare the disc space, because several of the enhancements below depend on using a type=directory chroot.

      sudo sbuild-createchroot --make-sbuild-tarball=/srv/chroot/unstable-amd64-sbuild.tar.gz unstable `mktemp -d` http://deb.debian.org/debian

Updating chroot manually

The chroot should be up-to-date before building packages. Use the sbuild-update to perform updates.

First, note the name of the sbuild chroot to be updated. All sbuild chroots built with sbuild-createchroot will have a suffix of '-sbuild'. Thus to find the names of all sbuild chroots, run the following.

   1 schroot -l | grep sbuild

If you followed the setup instructions above, there should be one chroot named source:unstable-$arch-sbuild where $arch is the architecture installed on your machine.

After noting the name of your sbuild chroot, run the following.

   1 sudo sbuild-update -udcar unstable-$arch-sbuild

Or using its short form as:

   1 sudo sbuild-update -udcar u

The arguments '-udcar' will tell sbuild-update to run an apt-get update, dist-upgrade, clean, autoclean, and autoremove in the chroot. "u" stands for unstable.

You can also pass --apt-update --apt-distupgrade to the individual sbuild invocation to update the temporary copy of the build chroot, but this won't cause any changes to happen in the persistent copy of the chroot (in the .tar.gz file). So if you are building more than once, you should run sbuild-update instead of relying on this.

Building packages

With properly configured ~/.sbuildrc as above, you can imply run the following to build a package from the source directory of a debianized package.

   1 sbuild

Alternatively, you may pass in the '.dsc' file of a package generated by dpkg-buildpackage, git-buildpackage, and so forth so that it may be built with sbuild. For example, to build sbuild from its '.dsc' file, do the following.

   1 sbuild sbuild_*.dsc

Integration with gbp (gbp-buildpackage)

Sbuild can be integrated into gbp's workflow with little effort with properly configured ~/.sbuildrc as above with ~/.gbp.conf which includs:

[DEFAULT]
# the default build command:
builder = sbuild -A -s --source-only-changes -v -d unstable

Then, you can build package for normal source only upload and for source and binary upload just with:

   1 gbp buildpackage

(Of course, you can specify this via --git-builder option.)

More information on git packaging at PackagingWithGit

Speeding up build process

Consider configuring sbuild/schroot with tmpfs or eatmydata. Otherwise, running dpkg especially by adt-run will slow the build a lot.

sbuild with eatmydata

Edit the corresponding /etc/schroot/chroot.d/$dist-$arch-sbuild-$suffix to append the line to use eatmydata:

command-prefix=eatmydata

Note that piuparts invokes eatmydata by default and nested eatmydata invocations don't work. To deal with this pass --no-eatmydata to piuparts in your ~/.sbuildrc, or set up a separate schroot profile for piuparts as described above.

sbuild with tmpfs

You could configure /etc/fstab to mount all short term contents on tmpfs. (Added bonus: less access to precious SSD.)

# For speeding up sbuild/schroot and prevent SSD wear-out
none /var/lib/schroot/session        tmpfs uid=root,gid=root,mode=0755 0 0
none /var/lib/schroot/union/overlay  tmpfs uid=root,gid=root,mode=0755 0 0
none /var/lib/schroot/union/underlay tmpfs uid=root,gid=root,mode=0755 0 0
none /var/lib/schroot/unpack         tmpfs uid=root,gid=root,mode=0755 0 0
none /var/lib/sbuild/apt-keys        tmpfs uid=sbuild,gid=sbuild,mode=2770 0 0
none /var/lib/sbuild/build           tmpfs uid=sbuild,gid=sbuild,mode=2770 0 0

If you are using a type=directory chroot as described in "Setup" above, and you have sufficient memory, you can run builds in RAM for a huge speed increase. The build is performed in a tmpfs that is overlaid upon the base chroot. You need union-type=overlay in your /etc/schroot/chroot.d/sbuild-amd64-sbuild-<hash> file but that should be there by default if you followed the setup instructions above.

Using "ccache" with sbuild

ccache is a compiler wrapper that will cache compilation results (produced object files) from gcc and g++; if you repeatedly compile the same source code (or parts of it), ccache will greatly shorten compilation times by avoiding recompilation of files that it has cached earlier.

This is especially useful during package development, when you might have to rebuild a package with a long compilation phase several times. It is also effective with packages that are frequently updated, because often only a few files actually change during updates to a software.

In order to prepare your sbuild environment for ccache, first perform the following setup in the host environment (i.e., outside the chroot), as user root:

   1 dir=/var/cache/ccache-sbuild
   2 install --group=sbuild --mode=2775 -d $dir
   3 env CCACHE_DIR=$dir ccache --max-size 4G
   4 cat >>/etc/schroot/sbuild/fstab <<END
   5 $dir $dir none rw,bind 0 0
   6 END

This assumes that you trust all members of the sbuild group.

It is perfectly fine to share the cache among chroots, even for different architectures. ccache honours the compiler name, size and timestamp as well as the command line when calculating hash values. At least one of these will differ between builds of the same file for different architectures.

Next place the following script into $dir/sbuild-setup:

   1 cat >$dir/sbuild-setup <<END
   2 #!/bin/sh
   3 export CCACHE_DIR=$dir
   4 export CCACHE_UMASK=002
   5 export CCACHE_COMPRESS=1
   6 unset CCACHE_HARDLINK
   7 export PATH="/usr/lib/ccache:\$PATH"
   8 exec "\$@"
   9 END

and make it executable:

chmod a+rx $dir/sbuild-setup

Then for each chroot ($dist-$arch-sbuild) where you want to enable ccache

  1. Install ccache inside the chroot by running

     schroot -c source:$dist-$arch-sbuild -d /home apt-get install ccache
  2. and edit the corresponding configuration file in /etc/schroot/chroot.d/ by appending the line

     command-prefix=/var/cache/ccache-sbuild/sbuild-setup

    (Multiple command-prefix can be joined with commas, in case you already have one configured; see eatmydata below.)

Using eatmydata and ccache with sbuild

If you want to combine eatmydata with the ccache instructions from above then use:

command-prefix=/var/cache/ccache-sbuild/sbuild-setup,eatmydata

Basic tips

Delete a chroot

sudo rm -r /srv/chroot/unstable-amd64-sbuild/
sudo rm /etc/schroot/chroot.d/unstable-amd64-sbuild-* /etc/sbuild/chroot/unstable-amd64-sbuild

Also see sbuild-destroychroot(1).

Cleaning up schroot session

Sometimes you can end up with dangling chroot sessions potentially taking up valuable system resources (find them with `schroot -l --all`). This command is useful:

sudo schroot --end-session --all-sessions

Customizations of sbuild chroots

Sometimes it is desirable to further customize your sbuild chroot environment. Typical customizations done are installing more packages inside the chroot, modifying /etc/apt/sources.list, and installing custom scripts to be run inside the chroot.

To modify a chroot, start a session for the chroot with the prefix 'source:'. For example, to modify the unstable-$arch-sbuild chroot, start a session for the chroot as follows.

   1 sudo sbuild-shell source:unstable-$arch-sbuild

Or using its short form as:

   1 sudo sbuild-shell u

This will start a session inside the unstable-$arch-sbuild chroot. Any modifications done inside the chroot will be saved upon exiting. Inside this chroot, you may run apt-get commands to install or remove packages as desired. For example, to install ccache, do the following in the chroot session.

   1 apt-get install ccache

Note that you are already root inside a chroot session. Also, sudo would typically not be installed in the chroot anyway.

Making other modifications such as editing /etc/apt/sources.list or adding scripts inside the chroot is best done from outside the chroot session. In order to do this, leave the current chroot session open and start another terminal session. In the other terminal session, find the path used for the existing chroot session as follows.

   1 schroot --info --all-sessions | grep Path

This should output exactly one line and should specify the path of the chroot session. It should look something like this.

  Path                   /var/lib/schroot/mount/unstable-amd64-sbuild-5bad48fe-9823-4454-815f-b869d1d7b22c

Doing an ls on this directory should resemble a standard listing of the '/' directory.

With the above path, the sources.list file will be in the following path.

/var/lib/schroot/mount/unstable-amd64-sbuild-5bad48fe-9823-4454-815f-b869d1d7b22c/etc/apt/sources.list

Open the sources.list file at this path with root privileges using your favorite editor, for example:

   1 sudo -e /var/lib/schroot/mount/unstable-amd64-sbuild-5bad48fe-9823-4454-815f-b869d1d7b22c/etc/apt/sources.list

Proceed to edit the sources.list file as you see fit, then save.

To add scripts inside the chroot, simply place the scripts in the following directory.

/var/lib/schroot/mount/unstable-amd64-sbuild-5bad48fe-9823-4454-815f-b869d1d7b22c/usr/local/bin

Be sure to make the scripts executable.

   1 sudo chmod a+x /var/lib/schroot/mount/unstable-amd64-sbuild-5bad48fe-9823-4454-815f-b869d1d7b22c/usr/local/bin/*

Other modifications may be done to the chroot, either by running commands available within the chroot session, or by running commands with root privileges via the secondary terminal session. Once you are done making modifications to the chroot, simply exit the session. Inside the chroot session, do the following.

   1 exit

After exiting, your modifications will be saved and made available for every new chroot session created afterwards.

Advanced Tips

Cross compiling

sbuild also supports cross-compiling a package: to build a package which is e.g. only buildable on mips, in the amd64 chroot from the above example, you can use:

   1 sbuild --host=mips

To build packages available from the apt repositories used in the sbuild chroot, just pass in a package name (older versions of sbuild required $package_$version). For example to build the latest sbuild:

   1 sbuild -d unstable sbuild

Everything needed to build the latest sbuild version will be downloaded from the repositories and will be saved in your current directory after building of the packages is finished.

External Commands

sbuild supports running external commands at various stages of the build process. This is useful for cases such as running a script inside the chroot after it has been setup. As an example, to run a script in /usr/local/bin/myscript, edit the $external_commands in the sbuild configuration file ~/.sbuildrc as follows.

   1 $external_commands = {
   2                         'post-build-commands' => [],
   3                         'chroot-setup-commands' => ['/usr/local/bin/myscript'],
   4                         'chroot-cleanup-commands' => [],
   5                         'pre-build-commands' => []
   6                       };

sbuild can also translate certain percent escaped keywords for external commands during certain portions of a build. For example, in post build commands, %SBUILD_CHANGES is changed to the path of the '.changes' file for a successfully built package.

Here is an example of adding a post build command to run /usr/local/bin/postbuildscript with %SBUILD_CHANGES as an argument.

   1 $external_commands = {
   2                         'post-build-commands' => ['/usr/local/bin/postbuildscript', '%SBUILD_CHANGES'],
   3                         'chroot-setup-commands' => ['/usr/local/bin/myscript'],
   4                         'chroot-cleanup-commands' => [],
   5                         'pre-build-commands' => []
   6                       };

See the 'EXTERNAL COMMANDS' section of the sbuild man page for more information on external commands.

Enabling experimental

The Debian experimental repository can be added dynamically on top of an existing unstable chroot during each sbuild run that requires experimental. You can use either the aspcud resolver (in use on the experimental buildds) or aptitude (used by *-backports).

sbuild --extra-repository='deb http://deb.debian.org/debian experimental main' --build-dep-resolver=aspcud mypkg.dsc

or

sbuild --extra-repository='deb http://deb.debian.org/debian experimental main' --build-dep-resolver=aptitude mypkg.dsc

If you need to test a build against a versioned Build-Depends from experimental, you can add --add-depends:

sbuild --extra-repository='deb http://deb.debian.org/debian experimental main' --build-dep-resolver=aspcud --add-depends='foo-dev (>= 1.2.3-4)' mypkg.dsc

Build for experimental

If you want to build for unstable but upload to experimental. Use schroot -l --all-source-chroots to get the name of the chroot (unstable-amd64-sbuild in this case).

sbuild -d experimental -c unstable-amd64-sbuild mypkg.dsc

Alternatively, if you know that you always want to build your packages for experimental in a sid chroot, just add experimental as an alias of your sid schroot to your sid schroot configuration:

aliases=experimental

Enabling incoming.debian.org

Another useful repository to add as --extra-repository option is deb http://incoming.debian.org/debian-buildd/ buildd-unstable main in case you want to build or do a new upload before the next dinstall

sbuild --extra-repository='deb http://incoming.debian.org/debian-buildd/ buildd-unstable main' mypkg.dsc

Disabling network access for dpkg-buildpackage

<!> This doesn't seem to work with recent sbuild (2016/05)

Source packages must be buildable without accessing any remote machines. On the other hand, the build process needs network access for the installation of the build dependencies. Conveniently, the build dependencies are installed by the "root" user while dpkg-buildpackage is run under fakeroot by the user running sbuild. So the following will deny any network access during the build process through blocking traffic originating from any process owned by the sbuild group while the root user will still have network access:

sudo iptables -I OUTPUT -m owner --gid-owner sbuild ! -d 127.0.0.0/8 -j DROP
sudo -u sbuild sbuild mypkg.dsc

A better fix would be if schroot allowed to unshare the network namespace for the dpkg-buildpackage invocation. See bugs 802850 and 802849

Using aliases

In Debian, an unstable chroot is used for building in a number of situations like building an unpacked source package with UNRELEASED in debian/changelog or building packages for experimental. Furthermore, distributions have alternative names like sid/unstable or experimental/rc-buggy. Sbuild selects the chroot to use either from debian/changelog (so it would be nice if UNRELEASED would trigger a build in an unstable chroot) or through the -d option which also sets the Distribution value in the resulting .changes file (so it would be handy if saying -d sid were enough and one wouldn't have to use the -c option to type unstable-amd64-sbuild manually). All of this can be solved by using schroot aliases. My sid schroot config says:

aliases=UNRELEASED,sid,rc-buggy,experimental

This means, that this schroot will be used for packages having UNRELEASED in their debian/changelog, for packages I build with -d sid (because writing out unstable is too long) as well as for packages I build for experimental.

Adding extra packages

It is often necessary to add extra binary packages as build dependencies. For example, you might want to make a package available as a build dependency that is waiting in the NEW queue and so isn't available from the mirrors. To do this, use the --extra-package=./foo.deb option to sbuild.

You might find that the output from the resolver is not helpful in determining which extra package you need to make available. In this case, it can be useful to pass --build-dep-resolver=aptitude which tends to provide more useful output (though you should remove it once you've figured out the problem).

Remote build servers

One advantage of cowbuilder over sbuild is that it supports offloading builds to a remote server with cowpoke. Unfortunately, that command is specifically crafted for cowbuilder, so you need something else for sbuild.

The trick is to create a source package and transfer it to the remote machine for building. The latter can be done with dcmd. Example:

dpkg-buildpackage -S
dcmd scp ../foo-1.0.dsc example.net:build-area
ssh example.net sbuild build-area/foo-1.0.dsc

Validate package cleanup

Packages will fail to build twice in a row if the clean target of debian/rules do not restore the source directory to its initial state. Adding the following to your ~/.sbuildrc will help you to detect modifications:

$external_commands = {
    "starting-build-commands" => [
        'bash -c \'find %SBUILD_PKGBUILD_DIR -print0 |
                  sort -z |
                  while read -d $\'\\\'\'\0\'\\\'\' file; do
                      echo -n "$(stat -c "%n %F %%s" "${file}") "
                      if [ -f "${file}" ]; then
                          sha256sum "${file}" |
                              cut -d " " -f 1
                      else
                              echo
                      fi
                  done > /tmp/file-list.pre-build\''
    ],
    "chroot-cleanup-commands" => [
        'cd %SBUILD_PKGBUILD_DIR && ./debian/rules clean',
        'bash -c \'find %SBUILD_PKGBUILD_DIR -print0 |
                  sort -z |
                  while read -d $\'\\\'\'\0\'\\\'\' file; do
                      echo -n "$(stat -c "%n %F %%s" "${file}") "
                      if [ -f "${file}" ]; then
                          sha256sum "${file}" |
                              cut -d " " -f 1
                      else
                              echo
                      fi
                  done > /tmp/file-list.post-build\'',
        'diff /tmp/file-list.pre-build /tmp/file-list.post-build'
    ]
};

Missing space in /build

It is possible that you lack space for builds even if /srv/chroot has plenty of space. This can happen at build time on large packages (e.g. Libreoffice) because sbuild decompresses the packages in /build in the chroot, which is a bind mount to /var/lib/sbuild/build. If you are on a workstation where /var is shared with the root partition, you may sometimes not have enough space for the largest packages. The symptom will be an error message like this:

E: Disc space is probably not sufficient for building.
I: Source needs 2703644 KiB, while 4089748 KiB is free.)

But then when you actually look at the df, you have plenty of space! This happens because sbuild cleans up after itself on failure and gives back the disk space. If you follow disk space usage more closely during the build, you will notice that /var will take up more and more space until that failure.

A workaround for this is to change the configuration of the /build bind mount. This is done in /etc/schroot/sbuild/fstab. For example, the following configuration uses /home/build instead:

# Mount a large scratch space for the build, so we don't use up
# space on an LVM snapshot of the chroot itself.
#/var/lib/sbuild/build  /build   none    rw,bind         0       0
/home/build  /build   none    rw,bind         0       0