Gentoo Docker image with distcc

Decrease Gentoo compilation times by leveraging spare resources, such as an Ubuntu or Windows box idling around. Docker is the only prerequisite.

Important

The SSH image variants have been deprecated as of 2025-05-16 in order to ease maintenance and reduce resource usage. No SSH images will be built moving forward. As an alternative, consider using the TCP image variants either with a VPN (recommended) or a reverse SSH tunnel.

Features

• Out-of-the-box support for the following Gentoo architectures:
  • amd64
  • arm
  • arm64
  • ppc64
  • x86
• Server-side caching using ccache
• Cross-compilation support using crossdev

Note

Only the stable toolchain of these architectures is supported.

Usage

On the worker node(s), run the containerized distcc server (distccd):

docker run -d -p 3632:3632 --name gentoo-distcc --rm ksmanis/gentoo-distcc:tcp

distccd should now be accessible from all interfaces at port 3632 (0.0.0.0:3632).

Note

Only private IP addresses are allowed to connect to distccd by default.

Command-line arguments are passed on verbatim to distccd. For instance, you can turn on the built-in HTTP statistics server:

docker run -d -p 3632-3633:3632-3633 --name gentoo-distcc --rm ksmanis/gentoo-distcc:tcp --stats

The statistics server should now be accessible from all interfaces at port 3633 (0.0.0.0:3633).

For a full list of options refer to distccd(1).

Ccache

If you share a worker instance between multiple clients, you might be interested in enabling server-side caching with ccache to avoid redundant recompilations. To do so, pull the tcp-ccache tag:

docker run -d -p 3632:3632 --name gentoo-distcc-ccache --rm ksmanis/gentoo-distcc:tcp-ccache

The directory /var/cache/ccache automatically persists in an anonymous Docker volume, but a named Docker volume or a bind mount may also be used for stronger persistence guarantees.

Ccache statistics can be queried as follows:

docker exec gentoo-distcc-ccache ccache -sv

Crossdev

All amd64 image variants support cross-compilation for the arm64 architecture (specifically the aarch64-unknown-linux-gnu toolchain) and vice versa: all arm64 image variants support cross-compilation for the amd64 architecture (specifically the x86_64-pc-linux-gnu toolchain). In other words, an amd64 desktop can be used to cross-compile for an arm64 Raspberry Pi and vice versa.

Cross-compilation support is enabled out of the box without any user configuration. More architecture combinations can be added upon request.

Testing

A manual way to test the containers is to compile a sample C file:

#include <stdio.h>

int main() {
    printf("Hello, distcc!\n");
    return 0;
}

DISTCC_HOSTS="127.0.0.1:3632" DISTCC_VERBOSE=1 distcc gcc -c main.c -o /dev/null