We have been using the node:8 image as the base of our Hobnob image. However, like Elasticsearch, Node Docker images come in many flavors:

• standard: This uses buildpack-deps:jessie as its base image. buildpack-deps is an image that provides a collection of the most common build dependencies, such as the GNU Compiler Collection (gcc.gnu.org) and GNU Make (gnu.org/software/make/). The buildpack-deps:jessie image is, itself, based on the debian:jessie Debian 8 image.
• slim: This is the same as the standard image, but does not contain all the build dependencies. Instead, it only contains curl, wget, ca-certificates, and the minimal set of packages that are required to work with Node.
• stretch: This is similar to the standard flavor, but uses Debian 9 (Stretch) instead of Debian 8 (Jessie).
• alpine: The standard and slim flavors use Debian as its base image. The alpine flavor uses Alpine Linux as its base image. Alpine is a distribution which is extremely lightweight, and thus its images are also smaller than others.

If we look at the Docker images for all the popular Linux distributions, you’ll find that alpine is, by far, the smallest:

$ docker images
REPOSITORY   TAG       IMAGE ID        CREATED        SIZE
alpine       latest    3fd9065eaf02    4 months ago   4.15MB
ubuntu       latest    452a96d81c30    2 weeks ago    79.6MB
debian       latest    8626492fecd3    2 weeks ago    101MB
opensuse     latest    35057ab4ef08    3 weeks ago    110MB
centos       latest    e934aafc2206    5 weeks ago    199MB
fedora       latest    cc510acfcd70    7 days ago     253MB

Keeping a container lightweight is important, as it affects how quickly a container can be deployed. Let's pull the more lightweight Node Docker images and compare them:

$ docker pull node:8-alpine
$ docker pull node:8-slim
$ docker images node
REPOSITORY TAG IMAGE ID CREATED SIZE
node 8-slim 65ab3bed38aa 2 days ago 231MB
node 8-alpine fc3b0429ffb5 2 days ago 68MB
node 8 78f8aef50581 2 weeks ago 673MB

As you can see, the node:8-alpine image is the smallest. So, let’s use that as our base image. Just to recap, your Docker image should now look like this:

FROM node:8-alpine
 
USER node
WORKDIR /home/node

COPY --chown=node:node ["package*.json", "yarn.lock", "./"]
RUN ["yarn"]
COPY --chown=node:node . .
RUN ["yarn", "run", "build"]

CMD ["node", "dist/index.js"]

Now, let’s remove the previous hobnob image and build a new one:

$ docker rmi hobnob:0.1.0
$ docker build -t hobnob:0.1.0 . --no-cache
$ docker images
REPOSITORY   TAG      IMAGE ID         CREATED          SIZE
hobnob       0.1.0    e0962ccc28cf     9 minutes ago    210MB

As you can see, the size of our image has decreased from 814 MB to 210 MB – a 74% decrease!