Reducing nodejs Docker images size by %50 using multi-stage builds and Zeit pkg.

Update: You might want to try the interactive tutorial I wrote for this blogpost: http://training.play-with-docker.com/node-zeit-pkg/ A week ago announced a new project called pkg ( which allows to bundle applications and all it’s dependencies (even the node runtime) in a single dynamically linked binary that can be easily shipped to different environments. This is very useful because it makes packaging, deploying and running your app extremely simple by handling just one binary instead of dealing with different dependencies and node runtimes. Zeit https://github.com/zeit/pkg) nodejs If you’re currently using nodejs + docker in your project, it’s most likely that you’re relying on any of different official nodejs ( ) images. As you may already know, these images are not usually lightweight as they need the runtime and also include other tools like which results in 200+MB images starting from the alternatives. https://hub.docker.com/_/node/ node npm slim At the same time, Docker announced a new feature called multi-stage builds (https://blog.docker.com/2017/04/dockercon-2017-day-1-highlights/) which helps to build docker images that usually have a different and context. build prod multi-stage build feature is only available in latest Docker 17.05-rc’s for the moment. Make sure to have a proper Docker version before trying the examples below or you’ll get some errors. I’ll show you now, how combining both these features you can build and ship extremely small and optimized nodejs docker images. First, we’ll create a small nodejs project, let’s start with a simple and index.js package.json index.js: console.log('Hello, pkg!'); package.json: {"name": "pkg-sample","bin": "index.js"} We’ll create our Dockerfile that uses pkg and multi-stage builds now: Dockerfile: FROM node:boron RUN npm install -g pkg pkg-fetch ENV NODE node6ENV PLATFORM linuxENV ARCH x64 RUN /usr/local/bin/pkg-fetch ${NODE} ${PLATFORM} ${ARCH} COPY . /app WORKDIR /app RUN /usr/local/bin/pkg --targets ${NODE}-${PLATFORM}-${ARCH} index.js FROM debian:jessie-slim COPY --from=0 /app/index / CMD ["/index"] In this particular case as you can see in the Dockerfile, we’re targeting a runtime. You have several options you can combine depending on the runtime you need, for example you can just the standard platform instead of linux if you wish. Refer to the pkg documentation for more details. node6, linux and x86_64 alpine Now, you can build your app image as before with . Once your image is built you’ll notice it’s size will be only a couple of megs and you’ll be able to run it just like any other docker container with docker build -t myapp . docker run myapp is how hackers start their afternoons. We’re a part of the family. We are now and happy to opportunities. Hacker Noon @AMI accepting submissions discuss advertising & sponsorship To learn more, , , or simply, read our about page like/message us on Facebook tweet/DM @HackerNoon. If you enjoyed this story, we recommend reading our and . Until next time, don’t take the realities of the world for granted! latest tech stories trending tech stories