shinsenter/alpine-s6 repository overview

⁠Linux Docker images with s6-overlay

🌏 Latest Linux Docker base images featuring autorun and s6-overlay.

⁠Table of Contents

• Introduction⁠
• Docker Image Variants⁠
• Usage⁠
• Application Directory⁠
• Customizing Container User and Group in Docker⁠
• Hooks⁠
• Autorun Scripts⁠
• Using Cron Jobs⁠
• Debug Mode⁠
• Other System Settings⁠
• Contributing⁠
• License⁠

⁠Introduction

Combine official Ubuntu⁠, Debian⁠, and Alpine Linux⁠ Docker images with s6-overlay⁠ and an autorun mechanism. This setup simplifies the process of building portable, production-ready application containers across various architectures.

⁠Docker Image Variants

The Docker images are available for Debian, Ubuntu and Alpine versions.

⁠Ubuntu

• Docker Hub: https://hub.docker.com/r/shinsenter/ubuntu-s6⁠
• GitHub Packages: https://code.shin.company/php/pkgs/container/ubuntu-s6⁠

⁠Debian

• Docker Hub: https://hub.docker.com/r/shinsenter/debian-s6⁠
• GitHub Packages: https://code.shin.company/php/pkgs/container/debian-s6⁠

⁠Alpine

• Docker Hub: https://hub.docker.com/r/shinsenter/alpine-s6⁠
• GitHub Packages: https://code.shin.company/php/pkgs/container/alpine-s6⁠

⁠Usage

Build and try the following Dockerfile examples:

⁠Ubuntu

FROM shinsenter/ubuntu-s6:latest

# Add your instructions here
# For example:
# ADD --chown=$APP_USER:$APP_GROUP ./myproject/ /var/www/html/

⁠Debian

FROM shinsenter/debian-s6:latest

# Add your instructions here
# For example:
# ADD --chown=$APP_USER:$APP_GROUP ./myproject/ /var/www/html/

⁠Alpine

FROM shinsenter/alpine-s6:latest

# Add your instructions here
# For example:
# ADD --chown=$APP_USER:$APP_GROUP ./myproject/ /var/www/html/

⁠Application Directory

The default application directory is /var/www/html and can be customized via the $APP_PATH environment variable:

docker run -v "$PWD":/app -e APP_PATH=/app shinsenter/debian-s6:latest

This changes the web application directory to /app.

⁠Customizing Container User and Group in Docker

Override the default user and group settings by setting environment variables when running the container.

Available variables:

For example, to run a container as user myapp with UID 5000:

docker run -e APP_USER=myapp -e APP_UID=5000 shinsenter/debian-s6:latest

Or in a docker-compose.yml:

services:
  web:
    image: shinsenter/debian-s6:latest
    environment:
      APP_USER: "myapp"
      APP_UID: "5000"

⁠Hooks

Hooks are useful for customizing the behavior of a running container.
These images support the following hooks:

To use hooks, create a hooks folder inside $APP_PATH and add executable files named after the hook, or in subfolders with the same name. Example: to install PHP modules at first-run, add a script hooks/first-run or hooks/first-run/install-modules.

Set DEBUG=1 to see which hooks are executed.

⁠Autorun Scripts

Shell scripts placed in the /startup/ directory will automatically run when the container starts, in alphabetical order by filename. This feature can initialize projects before the main program runs, saving time by executing initialization scripts automatically.

⁠Usage Example

Copy a script called 00-migration into /startup/ via a Dockerfile:

FROM shinsenter/debian-s6:latest

ADD ./autorun/00-migration /startup/00-migration
RUN chmod +x /startup/00-migration

# Add your instructions here
# For example:
# ADD --chown=$APP_USER:$APP_GROUP ./myproject/ /var/www/html/

⁠Disable Autorun Scripts

To disable autorun scripts, set DISABLE_AUTORUN_SCRIPTS=1 as an environment variable.

For example, with docker run:

docker run -e DISABLE_AUTORUN_SCRIPTS=1 shinsenter/debian-s6:latest bash

Or in docker-compose.yml:

services:
  web:
    image: shinsenter/debian-s6:latest
    environment:
      DISABLE_AUTORUN_SCRIPTS: "1"

⁠Using Cron Jobs

To enable cron jobs in containers, you can start the container with ENABLE_CRONTAB=1. This setting activates the Crontab service, which loads settings from the directory specified by $CRONTAB_DIR (default is /etc/crontab.d).

The cron jobs will run as the user defined by $APP_USER:$APP_GROUP, which by default is www-data:www-data, and with the home directory set by $CRONTAB_HOME (default is /var/www/html).

Here is an example Dockerfile to add a crontab:

FROM shinsenter/debian-s6:latest

ENV ENABLE_CRONTAB=1

# create crontab entry via RUN instruction
RUN echo '* * * * * echo "echo This line will run every minute!" | tee /tmp/cron-every-minute.txt' >> /etc/crontab.d/sample1;

# or copy crontab entries via ADD instruction
ADD ./sample2 /etc/crontab.d/

The format of a crontab entry is as follows:

# Job definition:
# .---------------- minute (0 - 59)
# |  .------------- hour (0 - 23)
# |  |  .---------- day of month (1 - 31)
# |  |  |  .------- month (1 - 12) OR jan,feb,mar,apr ...
# |  |  |  |  .---- day of week (0 - 6) (Sunday=0 or 7) OR sun,mon,tue,wed,thu,fri,sat
# |  |  |  |  |
# *  *  *  *  *  command to be executed

You can also easily set up cron jobs through the $CRONTAB_SETTINGS environment variable in the docker-compose.yml file. When the container starts, these settings are loaded into crontab, giving you more flexibility to change them later.

services:
  web:
    image: shinsenter/debian-s6:latest
    environment:
      ENABLE_CRONTAB: "1"
      CRONTAB_SETTINGS: "* * * * * echo 'This line will run every minute!' | tee /tmp/cron-every-minute.txt"

For more information on environment variables for cron jobs, refer to the Other System Settings⁠ section below.

⁠Debug Mode

Enable "debug mode" for more verbose logging by setting DEBUG=1 as an environment variable. This can be used both with docker run and in docker-compose.yml.

⁠Command Line

docker run -e DEBUG=1 shinsenter/debian-s6:latest bash

⁠docker-compose.yml

services:
  web:
    image: shinsenter/debian-s6:latest
    environment:
      DEBUG: "1"

⁠Other System Settings

These Docker images include additional environment variables for fine-tuning container behavior:

⁠Contributing

If you find these images useful, consider donating via PayPal⁠ or opening an issue on GitHub⁠.

Your support helps maintain and improve these images for the community.

⁠License

This project is licensed under the terms of the GNU General Public License v3.0⁠.

Please respect the intellectual efforts involved in creating these images. If you intend to copy or use ideas from this project, proper credit is appreciated.

From Vietnam 🇻🇳 with love.