Build a Gentoo Base System in a Container

Run ./gentoo-init.docker to fetch the latest Gentoo stage3 image and use this as a basis to build a new @system image intended to act as the base on which to build further binary packages. Be warned that this process may take several hours even with all dependent packages pre-built as binaries.

./gentoo-build-pkg.docker <package> will then use the resulting image to build the specified package and store the result persistently on the host as a binary package.

Gentoo's Portage allows many configuration files beneath /etc/portage to be represented as a single file, or as multiple files within a directory of the same name. Due to the need to merge elements from the host and elements from the build-system, the container build process requires some of these configuration elements to be represented as directories. If this is required but not the case on the host system, the build process will advise of the fix required.

The file gentoo-base/etc/portage/package.use.build/package.use.local may be used to represent any host-specific configuration conventionally located in /etc/portage/make.conf.

Please note: Certain elements may not work as intended if the overlay-repo srcshelton is not available on the system performing the container build - this configuration is largely untested.

N.B. This build system can be hosted by either docker or podman, and they will be searched for in this order. podman has proven more reliable over time, and so is the recommended option. However, the podman packages available with certain distributions and for certain architectures are very outdated - and upstream binary availability is poor - so docker is still used if both are present.

If upgrading from a packaged release of podman to a more current binary when the original has already been executed at least once, it may be necessary to remove the file /dev/shm/libpod_lock and then run podman system renumber.

Getting started

In an environment which requires a Linux VM to host containers (e.g. macOS, etc):

cp common/local.sh . && eval "${EDITOR} local.sh"
./podman-machine-init.sh --init

On a host running a non-Gentoo Linux distribution:

cp common/local.sh . && eval "${EDITOR} local.sh"
./podman-machine-init.sh --host
sudo ./gentoo-init.docker

On Gentoo Linux:

eval "${EDITOR} common/local.sh"
sudo ./sync-portage.sh
sudo dispatch-conf
sudo ./gentoo-init.docker

Container Images

gentoo-env

• Empty stage with global environment variables set;

gentoo-stage3

• Latest Gentoo stage3 image, copied on top of env image to preserve environment;

gentoo-init

• gentoo-stage3, with additional filesystem setup and entrypoint which will install @system to a separate build-root when the container is invoked;

gentoo-base

• Intermediate stage3 with with a new @system installed to a build-root, committed by running gentoo-init rather than built from a Containerfile file;

gentoo-build

• @system deployment relocated to the container root, ready to be used as the build environment to create new binary packages.