Tag Archive for 'docker'

Creating a Minimally Sized Docker Image

dockerThis is a follow up to the Publishing a Static AngularJS Application with Docker post.

Relative to the size of a standard Ubuntu Docker image I thought the 250MB CoreOS image was “lean”. Earlier this month I went to a Docker talk by Brian DeHamer and learned that there are much smaller Linux base images available on DockerHub. In particular, he mentioned Alpine which is only 5MB and includes a package manager.

Here are the instructions for building the same Apache server image from the previous post with Alpine.

The Dockerfile has significant changes:

Explanation of differences:

line 2: The base image is alpine:latest.

lines 4-5: Unlike the CoreOS image, the base Apline image does not include Apache. These lines use the apk package manager to install Apache2 and clean up after.

lines 6-7: Runs the exec form of the Dockerfile ENTRYPOINT command. This will run httpd in the background when the image is started.

line 8: The static web content is copied to a different directory.

Building and pushing the image to DockerHub is the same as before:

Because of the exec additions to the Dockerfile, the command line for starting the Docker image is simpler:

The resulting Docker image is only 10MB as compared to 290MB for the same content and functionality. Nice!

UPDATE (12-Jun-17): Here’s an even smaller image: Stuffing Angular into a Tiny Docker Container (< 2 MB)

Publishing a Static AngularJS Application with Docker


The most common use for JavaScript frameworks is to provide dynamic client-side user interface functionality for a web site. There are situations where a JS application does not require any services from its host server (see example unhosted apps). One of the challenges for this type of application is how to distribute it to end users.

This post will walk through creating a static AngularJS application (i.e. no back-end server) and how to create and publish a lean Docker container that serves the application content.  I will mention some tooling but discussion of setting up a JS development environment is beyond the scope of this article. There are many resources that cover those topics.

Also note that even though I’m using AngularJS, any static web content can be distributed with this method.

Side Note on AngularJS

One of the major advantages of using AngularJS over the many JavaScript framework alternatives is its overwhelming popularity. Any question or issue you may encounter will typically be answered with a simple search (or two).


With the recent AngularJS 2.0 controversy it will be interesting to see if this trend continues.

Creating an AngularJS application

The easiest way to create a full-featured Angular application is with Yeoman.  Yeoman is a Node.js module (npm) and along with its Angular generator creates a project that includes all of the build and test tools you’ll need to maintain an application.

Generate the Angular application with yo. Accepting all the defaults will include “Bootstrap and some AngularJS recommended modules.”  There’s probably more functionality included then you’ll need, but modules can be removed later.

The yo command will take a little while to complete because it has to download Angular and all of the modules and dependencies.

Start the server with Grunt (which needs to be installed separately).

The application can be viewed in a browser at http://localhost:9000/#/:


Building the Application Distribution

After removing the ‘Allo, Allo’ cruft and creating your custom application create a distribution with:

This will create a dist directory that contains the static application content.

Creating and Publishing the Docker Container

The prerequisite is of course to install Docker and create a Docker Hub account (free). See Docker Installation Documentation.

A typical Ubuntu Docker container requires more than a 1GB download. A leaner Linux distribution is CoreOs. The coreos/apache container has a standard Apache server and is only ~250MB.

Add a Dockerfile file to the myapp directory:

The key here is the COPY command which copies the content of the dist directory to the container /var/www directory. This is where the Apache server will find index.html and serve it on port 80 by default.  No additional Apache configuration is required.

Create the docker container:



Now push the container to your Docker hub account:

The dockeruser/myapp Docker container is now available for anyone to pull and run on their local machine or a shared server.

Starting the Application with Docker

The application can be started on a client system by downloading the running the dockeruser/myapp container.

The run command will download the container and dependencies if needed. The -d option runs the Docker process in the background while apache2ctrl is run in the container in the foreground. The application will be running on http://localhost:9001/#/.

To inspect the Apache2 logs on the running Docker instance:

To stop the server:

If you’ve pushed a new version of the application to Docker hub, users can update their local version with:

This example shows how Docker containers can provide a consistent distribution medium for delivering applications and components.



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