README.md

Node.js

The official Node.js docker image, made with love by the node community.

Table of Contents

• What is Node.js?
• How to use this image
  • Create a Dockerfile in your Node.js app project
    • Notes
  • Best Practices
  • Run a single Node.js script
  • Verbosity
    • Dockerfile
    • Docker Run
    • NPM run
• Image Variants
  • node:<version>
  • node:alpine
  • node:onbuild
  • node:slim
• License
• Supported Docker versions
• Governance and Current Members
  • Docker Working Group Members
  • Docker Working Group Collaborators

What is Node.js?

Node.js is a platform built on Chrome's JavaScript runtime for easily building fast, scalable network applications. Node.js uses an event-driven, non-blocking I/O model that makes it lightweight and efficient, perfect for data-intensive real-time applications that run across distributed devices.

See: http://nodejs.org

How to use this image

Create a Dockerfile in your Node.js app project

# specify the node base image with your desired version node:<version>
FROM node:6
# replace this with your application's default port
EXPOSE 8888

You can then build and run the Docker image:

$ docker build -t my-nodejs-app .
$ docker run -it --rm --name my-running-app my-nodejs-app

If you prefer Docker Compose:

version: "2"
services:
  node:
    image: "node:8"
    environment:
      - NODE_ENV=production
    volumes:
      - ./:/usr/src/app
    expose:
      - "8080"

You can then run using Docker Compose:

$ docker-compose up -d

Notes

The image assumes that your application has a file named package.json listing its dependencies and defining its start script.

It also assumes that you have a file named .dockerignore otherwise it will copy your local npm modules:

node_modules

Best Practices

We have assembled a Best Practices Guide for those using these images on a daily basis.

Run a single Node.js script

For many simple, single file projects, you may find it inconvenient to write a complete Dockerfile. In such cases, you can run a Node.js script by using the Node.js Docker image directly:

$ docker run -it --rm --name my-running-script -v "$PWD":/usr/src/app -w
/usr/src/app node:4 node your-daemon-or-script.js

Verbosity

By default the Node.js Docker Image has npm log verbosity set to info instead of the default warn. This is because of the way Docker is isolated from the host operating system and you are not guaranteed to be able to retrieve the npm-debug.log file when npm fails.

When npm fails, it writes it's verbose log to a log file inside the container. If npm fails during an install when building a Docker Image with the docker build command, this log file will become inaccessible when Docker exits.

The Docker Working Group have chosen to be overly verbose during a build to provide an easy audit trail when install fails. If you prefer npm to be less verbose you can easily reset the verbosity of npm using the following techniques:

Dockerfile

If you create your own Dockerfile which inherits from the node image you can simply use ENV to override NPM_CONFIG_LOGLEVEL.

FROM node
ENV NPM_CONFIG_LOGLEVEL warn
...

Docker Run

If you run the node image using docker run you can use the -e flag to override NPM_CONFIG_LOGLEVEL.

$ docker run -e NPM_CONFIG_LOGLEVEL=warn node ...

NPM run

If you are running npm commands you can use --loglevel to control the verbosity of the output.

$ docker run node npm --loglevel=warn ...

Image Variants

The node images come in many flavors, each designed for a specific use case. All of the images contain pre-installed versions of node, npm, and yarn. For each supported architecutre, the supported variants are different. In the file: architectures, it lists all supported variants for all of the architecures that we support now.

node:<version>

This is the defacto image. If you are unsure about what your needs are, you probably want to use this one. It is designed to be used both as a throw away container (mount your source code and start the container to start your app), as well as the base to build other images off of. This tag is based off of buildpack-deps. buildpack-deps is designed for the average user of docker who has many images on their system. It, by design, has a large number of extremely common Debian packages. This reduces the number of packages that images that derive from it need to install, thus reducing the overall size of all images on your system.

node:alpine

This image is based on the popular Alpine Linux project, available in the alpine official image. Alpine Linux is much smaller than most distribution base images (~5MB), and thus leads to much slimmer images in general.

This variant is highly recommended when final image size being as small as possible is desired. The main caveat to note is that it does use musl libc instead of glibc and friends, so certain software might run into issues depending on the depth of their libc requirements. However, most software doesn't have an issue with this, so this variant is usually a very safe choice. See this Hacker News comment thread for more discussion of the issues that might arise and some pro/con comparisons of using Alpine-based images. One common issue that may arise is a missing shared library required for use of process.dlopen. To add the missing shared libraries to your image, adding the libc6-compat package in your Dockerfile is recommended: apk add --no-cache libc6-compat

To minimize image size, it's uncommon for additional related tools (such as git or bash) to be included in Alpine-based images. Using this image as a base, add the things you need in your own Dockerfile (see the alpine image description for examples of how to install packages if you are unfamiliar).

node:onbuild

The ONBUILD image variants are deprecated, and their usage is discouraged. For more details, see docker-library/official-images#2076.

This image makes building derivative images easier. For most use cases, creating a Dockerfile in the base of your project directory with the line FROM node:onbuild will be enough to create a stand-alone image for your project.

While the onbuild variant is really useful for "getting off the ground running" (zero to Dockerized in a short period of time), it's not recommended for long-term usage within a project due to the lack of control over when the ONBUILD triggers fire (see also docker/docker#5714, docker/docker#8240, docker/docker#11917).

Once you've got a handle on how your project functions within Docker, you'll probably want to adjust your Dockerfile to inherit from a non-onbuild variant and copy the commands from the onbuild variant Dockerfile (moving the ONBUILD lines to the end and removing the ONBUILD keywords) into your own file so that you have tighter control over them and more transparency for yourself and others looking at your Dockerfile as to what it does. This also makes it easier to add additional requirements as time goes on (such as installing more packages before performing the previously-ONBUILD steps).

This onbuild variant will only install npm packages according to the package.json and does not adhere to the npm-shrinkwrap.json (see full discussion in nodejs/docker-node#65.

Note that npm installs devDependencies by default, which is undesirable if you're building a production image. To avoid this pass NODE_ENV as a build argument i.e. docker build --build-arg NODE_ENV=production ….

node:slim

This image does not contain the common packages contained in the default tag and only contains the minimal packages needed to run node. Unless you are working in an environment where only the Node.js image will be deployed and you have space constraints, we highly recommend using the default image of this repository.

License

License information for the software contained in this image. License information for the Node.js Docker project.

Supported Docker versions

This image is officially supported on Docker version 1.9.1.

Support for older versions (down to 1.6) is provided on a best-effort basis.

Please see the Docker installation documentation for details on how to upgrade your Docker daemon.

Governance and Current Members

The Node.js Docker Image is governed by the Docker Working Group. See GOVERNANCE.md to learn more about the group's structure and CONTRIBUTING.md for guidance about the expectations for all contributors to this project.

Docker Working Group Members

• Christopher Horrell (chorrell)
• Hans Kristian Flaatten (starefossen)
• Hugues Malphettes (hmalphettes)
• John Mitchell (jlmitch5)
• Peter Petrov (pesho)
• William Blankenship (retrohacker)

Docker Working Group Collaborators

• Mikeal Rogers (mikeal)
• Laurent Goderre (LaurentGoderre)
• Simen Bekkhus (SimenB)
• Peter Dave Hello (PeterDaveHello)