passenger-docker

# Docker base images for Ruby, Python, Node.js and Meteor web apps

<img src="http://blog.phusion.nl/content/images/2018/03/passenger-docker.jpg" width="500" alt="Docker">

Passenger-docker is a set of [Docker](https://www.docker.com) images meant to serve as good bases for **Ruby, Python, Node.js and Meteor** web app images. In line with [Phusion Passenger](https://www.phusionpassenger.com/)'s goal, passenger-docker's goal is to make Docker image building for web apps much easier and faster.

Why is this image called "passenger"? It's to represent the ease: you just have to sit back and watch most of the heavy lifting being done for you. Passenger-docker is part of a larger and more ambitious project: to make web app deployment ridiculously simple, to heights never achieved before.

**Relevant links:**
 [Github](https://github.com/phusion/passenger-docker) |
 [Docker registry](https://registry.hub.docker.com/r/phusion/passenger-full/) |
 [Discussion forum](https://groups.google.com/d/forum/passenger-docker) |
 [Twitter/X](https://twitter.com/phusion_nl) |
 [Blog](http://blog.phusion.nl/)

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**Table of contents**

 * [Why use passenger-docker?](#why_use)
 * [About passenger-docker](#about)
   * [What's included?](#whats_included)
   * [Memory efficiency](#memory_efficiency)
   * [Image variants](#image_variants)
 * [Inspecting the image](#inspecting_the_image)
 * [Using the image as base](#using)
   * [Getting started](#getting_started)
   * [The `app` user](#app_user)
   * [Using Nginx and Passenger](#nginx_passenger)
     * [Adding your web app to the image](#adding_web_app)
     * [Configuring Nginx](#configuring_nginx)
     * [Setting environment variables in Nginx](#nginx_env_vars)
     * [Application environment name (`RAILS_ENV`, `NODE_ENV`, etc)](#app_env_name)
   * [Using Redis](#redis)
   * [Using memcached](#memcached)
   * [Additional daemons](#additional_daemons)
   * [Using Ruby](#using_ruby)
     * [Selecting a default Ruby version](#selecting_default_ruby)
     * [Running a command with a specific Ruby version](#running_command_with_specific_ruby_version)
     * [Default wrapper scripts](default_ruby_wrapper_scripts)
   * [Running scripts during container startup](#running_startup_scripts)
   * [Upgrading the operating system inside the container](#upgrading_os)
   * [Upgrading Passenger to the latest version](#upgrading_passenger)
 * [Container administration](#container_administration)
   * [Running a one-shot command in a new container](#oneshot)
   * [Running a command in an existing, running container](#run_inside_existing_container)
   * [Login to the container via `docker exec`](#login_docker_exec)
     * [Usage](#docker_exec)
   * [Login to the container via SSH](#login_ssh)
     * [Enabling SSH](#enabling_ssh)
     * [About SSH keys](#ssh_keys)
     * [Using the insecure key for one container only](#using_the_insecure_key_for_one_container_only)
     * [Enabling the insecure key perm