Docker and Node.js

Build this image:

# Build and image named 'express-image' from the Dockerfile located here.
docker build --tag express-image .

Create a container with this image:

# Run a instance named 'express-container'.
docker run -d -p 5000:3000 --name express-container express-image

Now visit http://localhost:5000.

Notice the mapped the machine's port 5000 to the container's port 3000. This is also possible to map port 80 to expose the container to the default HTTP port.