Create your own Debian packages
Introduction
In my project to create a self-sufficient infrastructure, I sometimes find myself installing small programs on many machines with a Makefile or a series of commands. And even if it's pretty clean, it's not very practical when you manage a large quantity of servers. So I had the idea to package my programs to simplify the deployment on my machines.
So we will see how to create our own .deb packages !
The requirements are simple:
- Be on a Debian-based system
- Install the following packages:
sudo apt install build-essential binutils lintian debhelper dh-make devscripts
Create your own Debian package
I will take a simple example Kompose
It's a small script in Go allowing to convert docker-composes into YAML Kubernetes files. To install it, we download the compiled executable and we put it in a folder of our $PATH.
I would then like to create a .deb that would contain the Kompose binary and put it in /usr/bin.
The official Debian documentation (available here) is very clear: we have to create a directory which will be considered as the root of our system.
Let me explain:
If I want to drop the kompose file into my /usr/bin folder. I will then create the folder ./kompose_1.28.0-1_amd/usr/bin/.
The documentation offers us a very simple naming convention, You should name your files as follows
name_version-revision_architecture.deb
In my case, I name my folder kompose_1.28.0-1_amd64 (the .deb extension will be added at the package creation)
Now that we know how to drop files into the tree, we need to create the DEBIAN/control file.
This file gathers the metadata of the (Name, maintainer, architecture) file, it allows dpkg to name what we just installed and its version.
Package: kompose
Version: 1.28.0
Maintainer: Quentin JOLY <github@thoughtless.eu>
Architecture: amd64
Description: Kompose is a conversion tool for Docker Compose to container orchestrators such as Kubernetes (or OpenShift).
It is also possible to add conflicts with other packages, or conversely dependencies before/after installation.
Pre/Post scripts
If dropping files is not enough to install your package, it is still possible to run {post,pre}{inst,rm} scripts. These should be placed in the DEBIAN/ folder (the same as for the control file).
Here are the 4 possibilities of script launching:
- pre installation (
preinst) - post installation (
postinstall) - pre delete (
prerm) - post removal (
postrm)
The use of these scripts allows you to compile the necessary, drop the configuration files, or delete the logs after the deletion.
Create the archive
Here is our tree with the Kompose executable, my metadata file and my post-installation script.
└── kompose_1.28.0-1_amd64
├── DEBIAN
│ ├── control
│ └── postinst
└── usr
└── bin
└── kompose
Now, the command for creating our deb is dpkg-deb --build kompose_1.28.0-1_amd64.
➜ dpkg-deb --build kompose_1.28.0-1_amd64
dpkg-deb: building package 'kompose' in 'kompose_1.28.0-1_amd64.deb'.
Now we just need to send our kompose_1.28.0-1_amd64.deb file to a Debian machine and install it with sudo dpkg -i kompose_1.28.0-1_amd64.deb.
If you get the following error :
# dpkg -i kompose_1.28.0-1_amd64.deb
dpkg-deb: error: archive 'kompose_1.28.0-1_amd64.deb' uses unknown compression for member 'control.tar.zst', giving up
dpkg: error processing archive kompose_1.28.0-1_amd64.deb (--install):
dpkg-deb --control subprocess returned error exit status 2
Errors were encountered while processing:
kompose_1.28.0-1_amd64.deb
This is because Debian has changed the package encryption from zstd to xz. It is possible to solve this problem by extracting the contents of the .deb file, and recreating it using the following procedure:
file=kompose_1.28.0-1_amd64.deb
ar x $file
zstd -d < control.tar.zst | xz > control.tar.xz
zstd -d < data.tar.zst | xz > data.tar.xz
ar -m -c -a sdsd repacked_${file} debian-binary control.tar.xz data.tar.xz
rm debian-binary control.tar.xz data.tar.xz control.tar.zst data.tar.zst