93da5caa69
We've been effectively using the basearch of the host, making the stage non-reproducible: if the same pipeline was run on machines with different architectures, it would produce different results. However, pipelines producing different outputs must be different. Thus, this patch includes the basearch in the pipeline. In principle, this allows cross-arch builds. dnf should be the only stage running binaries from the target tree. This is not yet tested.
3.6 KiB
osbuild
A build system for operating system images, working towards an image build pipeline that's more comprehensible, reproducible, and extendable.
Pipelines
The build process for an image is described by a pipeline. Each stage in a pipeline is a program that, given some configuration, modifies a file system tree. Finally, an assembler takes a filesystem tree, and assembles it into an image. Pipelines are defined as JSON files like this one:
{
"name": "Example Image",
"stages": [
{
"name": "org.osbuild.dnf",
"options": {
"releasever": "30",
"basearch": "x86_64",
"repos": {
"fedora": {
"name": "Fedora",
"metalink": "https://mirrors.fedoraproject.org/metalink?repo=fedora-$releasever&arch=$basearch",
"gpgkey": "file:///etc/pki/rpm-gpg/RPM-GPG-KEY-fedora-$releasever-$basearch"
}
},
"packages": [ "@Core", "grub2-pc", "httpd" ]
}
},
{
"name": "org.osbuild.systemd",
"options": {
"enabled_services": [ "httpd" ]
}
},
{
"name": "org.osbuild.grub2",
"options": {
"root_fs_uuid": "76a22bf4-f153-4541-b6c7-0332c0dfaeac"
}
}
],
"assembler": {
"name": "org.osbuild.qcow2",
"options": {
"filename": "example.qcow2",
"root_fs_uuid": "76a22bf4-f153-4541-b6c7-0332c0dfaeac",
"size": 3221225472
}
}
}
osbuild runs each of the stages in turn, isolating them from the host and
from each other, with the exception that they all operate on the same
filesystem-tree. The assembler is similarly isolated, and given the same
tree, in read-only mode and assembles it into an image without altering
its contents.
The filesystem tree produced by the final stage of a pipeline, is named and optionally saved to be reused as the base for future pipelines.
Each stage is passed the (appended) options object as JSON over stdin.
The above pipeline has no base and produces a qcow2 image.
Running
usage: python3 -m osbuild [-h] [--build-pipeline PIPELINE] [--store DIRECTORY]
[-l DIRECTORY] -o DIRECTORY
PIPELINE
Build operating system images
positional arguments:
PIPELINE json file containing the pipeline that should be built
optional arguments:
-h, --help show this help message and exit
--build-pipeline PIPELINE
json file containing the pipeline to create a build
environment
--store DIRECTORY the directory where intermediary os trees are stored
-l DIRECTORY, --libdir DIRECTORY
the directory containing stages, assemblers, and the
osbuild library
required named arguments:
-o DIRECTORY, --output DIRECTORY
provide the empty DIRECTORY as output argument to the
last stage
Running example
You can build basic qcow2 image of Fedora 30 by running a following command:
sudo python3 -m osbuild -o output --libdir . samples/base-qcow2.json
-
Root rights are required because osbuild heavily relies on creating systemd containers and bind mounting.
It shouldn't interfere with host OS but please be careful! It's still under development!
-
--libdirargument is required becauseosbuildexpects itself to be installed in directories under/usr. Using this argument you can change the expected path. -
You don't need to use any kind of virtual environment, modern version of Python 3 is enough.
osbuilduses only standard library and linux commands.