Docker base image

A Multi-arch base Alpine image with runit and syslog-ng

Introduction

This Docker image is based on Alpine linux and is intended to be used ad a base image to run services inside a container. On top of Alpine, runit is used as init scheme and service supervisor and syslog-ng is used to collect logs and redirect it to Docker logs (via stderr and stdout).

Multi-Architecture

This image is built with multiple CPU architecture support.
As stated in Docker best-practice, the image is tagged and released with current version tag for many cpu architectures and a manifest "general" version tag, which automatically points to the right architecture when you use the image.

I also add the "latest" manifest tag every time I release a new version.

How to use

Use as base image

The image is available on the Docker hub and can be used as base image to build your own project.

FROM edofede/baseimage:<VERSION>

Container creation

You can simply create and start a Docker container from the image on the Docker hub by running:

docker create --name BaseImage edofede/baseimage:latest
docker start BaseImage

Then you can launch bash or other commands inside:

docker exec -ti BaseImage bash

If, instead, you want to run the image one-shot, without starting services, use:

docker run -ti --rm edofede/baseimage:latest bash

Entrypoint

The entrypoint script (/entrypoint.sh) accepts arguments. These are launched on the container, instead of starting runit and related services.

Setup

Run one-shot script at boot

To run one or more scripts at container boot, insert (or symlink) it inside /etc/runit/1.d/ folder. All scripts/programs inside this folder will be launched before services starts. If one fails, the container enters in shutdown mode.

Add new service

To add a new service, create a new folder inside /etc/sv/ and add the "run" script inside.

Example (/etc/sv/syslog-ng/run):

#!/usr/bin/env sh
set -eu
exec 2>&1

/usr/sbin/syslog-ng --foreground

Configure all services to run in foreground mode, so runit can handle it correctly.

Then link the service folder inside /etc/service directory. Example:

ln -sf /etc/sv/syslog-ng /etc/service/

For additional information or advanced configuration, please read the runit guide.

Set timezone

The image comes with tzdata already installed (and timzone setted to Europe/Rome). To set a new timezone, launch a bash command and follow this guide (skip the first command).

Support me

I treat these free projects exactly like professional works and I'm glad to share it, with some of my knowledge, for free.

If you found my work useful and want to support me, you can donate me a little amount