Translation(s): none
Contents
- What is sbuild
- Setup
- Building packages
- Basic tips
-
Advanced Tips
- Cross compiling
- External Commands
- Enabling experimental
- Build for experimental
- Enabling incoming.debian.org
- Disabling network access for dpkg-buildpackage
- Using aliases
- Adding extra packages
- Remote build servers
- Validate package cleanup
- Associated schroot environment for development
- Missing space in /build and /srv/chroot
- Using /var/cache/apt/archives/ as package cache
What is sbuild
What is sbuild:
sbuild is a convenience wrapper script of schroot to build binary package easily under specified chroot.
sbuild is used on the official buildd network to build binary and source packages for all supported architectures.
- This helps good and timely code updates along Debian changes.
sbuild can also be used by individuals to test that their package builds in a minimal installation of Debian Unstable
sbuild now can help ensure that you haven't missed any build dependencies. (This feature was the advantage for pbuilder/cowbuilder over buildd)
sbuild can help ensure the goodness of package by integrating lintian, piuparts, autopkgtest
sbuild can optionally produce a .changes file suitable for making a source-only upload using classic dput.
This last feature allows you to skip a separate dpkg-buildpackage -S execution after doing a final test binary build.
This last feature is irrelevant if you use modern dgit push-source for source-only uploads.
sbuild is fundamentally a tool for making binary builds. None of its isolation and testing features are actually relevant for making source-only uploads.
The alternative to sbuild are
pbuilder combined with cowbuilder (older code base)
propellor platform. (its Propellor.Property.Sbuild module can perform most of this setup for you.)
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
When using sbuild, there are many ways to use it.
In all cases, we assume you are running at least Debian 11 bullseye using a type=directory chroot.
Option 1: Using unshare with mmdebstrap (no root needed)
Rather than creating a chroot directory, a tarball is created using mmdebstrap as the base chroot. The chroot base tarball can be tweaked using the options of mmdebstrap, like loading a custom apt sources configuration. Sbuild uses the tarball as a base for a chroot in a temporary directory to execute the build.
1. Install necesary packages:
1 sudo apt install sbuild mmdebstrap uidmap
2. Prepare necesary directories
1 mkdir -p ~/.cache/sbuild
3. Create/Update the tarballed chroot
1 mmdebstrap --variant=buildd unstable ~/.cache/sbuild/unstable-amd64.tar.zst
You can use several compression algorithms for the tarball. They will be autodetected depending on the extension.
As of May 2024, ZST seems to provide the best size/time ratio. It certainly is the fastest.
Time comparison for a Dell Precision 3800M, 16GB RAM, on an SSD drive (a computer form early 2015).
Format |
Tarball size |
Time |
.xz |
~100MB |
179,60s user 7,09s system 75% cpu 4:07,49 total |
.gz |
~150MB |
38,51s user 6,13s system 83% cpu 53,423 total |
.zst |
~139MB |
22,68s user 6,28s system 74% cpu 38,868 total |
If you use plain .tar as the extension, then no compression at all will be used. You can use that option on slow hardware where you don't care about a few hundred MB more in disk space utilization.
Executing below command including the EOF-heredoc will create a new ~/.sbuildrc. It will overwrite an existing file, so make sure you do not already have an ~/.sbuildrc or create a backup copy as needed.
Option 2: 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
You may still want to further customize setting manually as the following to enjoy additional optional features.
Option 3: Manual setup
This ~/.sbuildrc sets up sbuild in a way compatible with most contemporary Debian practices.
Tip: For creating a .sbuildrc file based on an example:
cp /usr/share/doc/sbuild/examples/example.sbuildrc $HOME/.sbuildrc
1 sudo apt-get install sbuild schroot debootstrap apt-cacher-ng devscripts piuparts
2 sudo tee ~/.sbuildrc << EOF
3 ##############################################################################
4 # PACKAGE BUILD RELATED (additionally produce _source.changes)
5 ##############################################################################
6 # -d
7 $distribution = 'unstable';
8 # -A
9 $build_arch_all = 1;
10 # -s
11 $build_source = 1;
12 # --source-only-changes (applicable for dput. irrelevant for dgit push-source).
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', '%r-%a-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 $LOGNAME
35 sudo ln -sf ~/.sbuildrc /root/.sbuildrc
... *logout* and *re-login* or use newgrp sbuild in your current shell
1 sudo sbuild-createchroot --include=eatmydata,ccache unstable /srv/chroot/unstable-amd64-sbuild http://127.0.0.1:3142/ftp.us.debian.org/debian
This invokes debootstrap with --variant=buildd option to install required, apt ,fakeroot and build-essential packages in addition to specified eatmydata, and ccache packages. This also configures /etc/hosts, /usr/sbin/policy-rc.d, and /etc/apt/sources.list in the newly created chroot environment. The schroot configuration /etc/schroot/chroot.d/sid-amd64-sbuild-$suffix for this newly created chroot is created in the host system as:
[sid-amd64-sbuild] description=Debian sid/amd64 autobuilder groups=root,sbuild root-groups=root,sbuild profile=sbuild type=directory directory=/srv/chroot/sbuild-createchroot union-type=overlay
The schroot created using sbuild-createchroot has a few more packages available by default than the ones used by debci (for example build-essential) so if you are adding or removing dependencies, it is recommended to test the autopkgtest using autopkgtest-build-lxc and autopkgtest your_package_dsc.dsc -- lxc -s -e autopkgtest-unstable at least once to make sure your package won't fail when running on debci due to missing dependencies.
Now for a brief explanation on what these commands do.
- Install sbuild and other useful packages onto the system.
- 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.)
- This setting allows you to avoid long commandline options for typical workflow needs and run all post-build tests.
Adjust parallel=5 to match your system resources.
Setting the $run_lintian variable to 0 instead will disable running of lintian.
Setting the $run_piuparts variable to 0 instead will disable running piuparts.
'--no-eatmydata' for piuparts is needed when you configure schroot with "command-prefix=eatmydata" in /etc/schroot/chroot.d/unstable-amd64-sbuild-*.
Setting the $run_autopkgtest variable to 0 instead will disable running autopkgtest.
See the sbuild.conf manpage for more options.
- Update the active user group set to include sbuild.
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.
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 )
Use of classic mirror server URLs such as http://ftp.us.debian.org instead of its modern http://deb.debian.org is intentional choice to avoid 986356 for apt-cacher-ng.
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://ftp.us.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 .
Updating chroot manually if you use unshare
Updating chroots is not supported, just create a new one.
Updating chroot manually (if you use root - for options 2 and 3)
The chroot should be up-to-date before building packages. Use the sbuild-update to perform updates.
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
All sbuild chroots built with sbuild-createchroot are created by schroot and will have a suffix of '-sbuild'. Thus to find the names of all sbuild chroots, run the following.
1 schroot -l | grep sbuild
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
Standalone
With properly configured ~/.sbuildrc as above, you can simply 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 includes:
[DEFAULT] # the default build command: builder = sbuild
(You can alternatively specify --git-builder=sbuild option to gbp command.)
Then, you can build package for normal source only upload and for source and binary upload just with:
1 gbp buildpackage
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. (If modern fast NVMe SSD is used as storage device, you may not see much speed differences as you see with HDD.)
sbuild with eatmydata
(If you are using unshare tmpfs is a better option)
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 (schroot)
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/sbuild/build tmpfs uid=sbuild,gid=sbuild,mode=2770 0 0
sbuild with tmpfs (unshare)
With trixie this is no longer needed as /tmp is a tmpfs already by default.
1 echo "\$unshare_tmpdir_template = '/dev/shm/tmp.sbuild.XXXXXXXXXX';" >> ~/.sbuildrc
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:
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:
and make it executable:
1 chmod a+rx $dir/sbuild-setup
Then for each chroot ($dist-$arch-sbuild) where you want to enable ccache
Install ccache inside the chroot by running
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
Using ccache with sbuild in unshare mode
Add this to mmdebstrap when creating the chroot tarball:
1 --include=ccache --customize-hook='chroot "$1" update-ccache-symlinks'
(The update-ccache-symlinks is needed due to #632779)
Add this to your .sbuildrc:
1 cat << "EOF" >> ~/.sbuildrc
2 $build_environment = { "CCACHE_DIR" => "/build/ccache" };
3 $path = "/usr/lib/ccache:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games";
4 $build_path = "/build/package/";
5 $dsc_dir = "package";
6 $unshare_bind_mounts = [ { directory => "$HOME/.cache/ccache", mountpoint => "/build/ccache" } ];
7 $autopkgtest_opts = [ '--apt-upgrade', '--env=CCACHE_DIR=/build/ccache', '--env=PATH=/usr/lib/ccache:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games', '--', 'unshare', '--release', '%r', '--arch', '%a', '--prefix=/dev/shm/tmp.autopkgtest.', '--bind', '$HOME/.cache/ccache', '/build/ccache' ];
8 EOF
Note that the sbuild user needs to have access to $HOME/.cache/ccache so either set chmod a+X to "$HOME" "$HOME/.cache" and chmod -R a+rwX "$HOME/.cache/ccache" or use a temporary directory for it.
Basic tips
Delete a chroot
Also see sbuild-destroychroot(1).
Note: You may be unable to completely delete a chroot sometimes with a failing message, "Device or resource busy". This may mean that chroot has open or active session(s) which you should close or end first. See below for how to end sessions.
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:
1 sudo schroot --end-session --all-sessions
Customizations of sbuild chroots
Sometimes it is desirable to further customize your sbuild chroot environment (type=directory) permanently. 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.
You start a root shell prompt inside the unstable chroot.
1 sudo sbuild-shell u
Here, "u" is short for "unstable". You can specify longer form such as unstable-amd64 here, too.
This starts a schroot session for source:unstable-$arch-sbuild. 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.
Modifications to /etc/apt/sources.list inside the unstable chroot can be done from outside the chroot with root privileges using your favorite editor as:
1 sudo -e /srv/chroot/unstable-amd64-sbuild/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 directory /srv/chroot/unstable-amd64-sbuild/usr/local/bin/
Be sure to make the scripts executable.
1 sudo chmod a+x /srv/chroot/unstable-amd64-sbuild/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.
Think negative impacts of modifications to the chroot environment used by the sbuild command before making modifications to it. If you simply want to have a chroot environment with many pre-loaded packages for debugging packages, it is better to set up a custom chroot environment using Schroot directly and use it.
Advanced Tips
Cross compiling
sbuild also supports cross-compiling a package to build for a different processor architecture e.g arm64 or ppc64el etc( if a package has an arch:all package option, then there's no point trying to cross build, since that's already arch independent): 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.
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.
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 the aspcud resolver (in use on the experimental buildds)
1 sbuild --extra-repository='deb http://deb.debian.org/debian experimental main' --build-dep-resolver=aspcud mypkg.dsc
To exactly mimic the resolver behaviour used by the official buildds you need to add aspcud preferences that minimise the number of packages from experimental. See the DSA puppet repository at https://salsa.debian.org/dsa-team/mirror/dsa-puppet/-/blob/production/modules/buildd/templates/sbuild.conf.erb
1 sbuild --extra-repository='deb http://deb.debian.org/debian experimental main' --build-dep-resolver=aspcud --aspcud-criteria '-count(solution,APT-Release:=/a=experimental/),-removed,-changed,-new' mypkg.dsc
You can also use aptitude (used by *-backports), which for most packages should have the same effects
1 sbuild --extra-repository='deb http://deb.debian.org/debian experimental main' --build-dep-resolver=aptitude mypkg.dsc
Another possibility is to have a dedicated ~/.sbuildrc.experimental configuration file and run sbuild via
1 SBUILD_CONFIG=~/.sbuildrc.experimental sbuild mypkg.dsc
with ~/.sbuildrc.experimental containing for example:
If you need to test a build against a versioned Build-Depends from experimental, you can add --add-depends:
1 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).
1 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
1 sbuild --extra-repository='deb http://incoming.debian.org/debian-buildd/ buildd-unstable main' mypkg.dsc
Disabling network access for dpkg-buildpackage
Using the unshare backend
The sbuild unshare backend disables network during the build by default. See above for documentation.
Using iptables
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:
A better fix would be if schroot allowed to unshare the network namespace for the dpkg-buildpackage invocation. See bugs 802850 and 802849
Using linux network namespaces
As an alternative, you can also use linux network namespace to isolate sbuild. In its most basic form, it will create a namespace with only the loopback interface (in a down state). This means no network access outside the namespace. Your dependencies must already be installed in the chroot. The main drawback of this method is that it requires root privileges.
Run the following to build your package without network access:
A more elaborate setup could include a pair of peer interfaces, shared between the main and no-net namespace, without default routes, fetching packages from a local proxy.
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:
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'
]
};
Associated schroot environment for development
For development, creating the latest minimal unstable chroot environment to execute programs in unstable environment as sbuild does is time consuming. Let’s create an associated package pre-loaded unstable chroot shell environment and use it directly from the schroot command. (This assumes you have already created chroot environment as above.)
1 $ sudo cp -a /srv/chroot/unstable-amd64-sbuild-$suffix /srv/chroot/unstable-amd64-dev
2 $ sudo cp -a /etc/schroot/desktop /etc/schroot/dev
3 $ sudo tee /etc/schroot/chroot.d/unstable-amd64-dev << EOF
4 [unstable-dev]
5 description=Debian unstable/amd64 chroot development environment
6 groups=root,sbuild
7 root-groups=root,sbuild
8 source-groups=root,sbuild
9 source-root-groups=root,sbuild
10 profile=dev
11 type=directory
12 preserve-environment=true
13 directory=/srv/chroot/unstable-amd64-dev
14 union-type=overlay
15 command-prefix=eatmydata
16 EOF
Let’s install basic build environment packages to this chroot in /srv/chroot/unstable-amd64-dev.
Let's further customize mount points by editing /etc/schroot/osamu/fstab as needed. Let's also copy setting from the host PC to the chroot as needed.
Let's add 2 shell alias definitions to ~/.bashrc on the host system as follows and enable convenient access to this chroot environment.
alias devs="schroot -c source:unstable-dev" alias devx="xhost +si:localuser:$(id -un) ; schroot -c chroot:unstable-dev ; xhost -"
The devs command opens a shell prompt and allows us to modify the source chroot environment. The changes made are persistent. This is good for installing and upgrading packages in the chroot.
The devx command opens a shell prompt and allows us to work in a chroot session to build a source tree with access to X applications such as gitk as usual. The changes made aren’t persistent.
Missing space in /build and /srv/chroot
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 of the chroot itself. #/var/lib/sbuild/build /build none rw,bind 0 0 /home/build /build none rw,bind 0 0
If /srv/chroot lacks space but some other directory has plenty of space, you can make space by adding the similar bind mount from the other directory to /srv/chroot.
Using /var/cache/apt/archives/ as package cache
1 sudo apt -o Dir::State::status=lock build-dep -d <pkg>
2 sudo apt -o Dir::State::status=lock install -d lintian
3 cd $(mktemp -d)
4 ln -s /var/cache/apt/archives/
5 apt-ftparchive packages . > Packages
6 apt-ftparchive release . > Release
7 python3 -m http.server 5678 --bind 127.0.0.1
8 sbuild --extra-repository="deb [trusted=yes] http://127.0.0.1:5678 ./" --chroot-setup-commands "rm /etc/apt/sources.list"