title: Docker: Dockerfile vs docker-compose.yml
body: <p>I have a <code>Dockerfile</code> as the following:</p>
  
  <pre><code>FROM docker/whalesay:latest
  RUN apt-get update &amp;&amp; apt-get install -y fortunes
  CMD while true; do /usr/games/fortune -a | cowsay; sleep 2; done
  </code></pre>
  
  <p>I have built the above <code>Dockerfile</code> as image: <code>docker-whale</code></p>
  
  <p>I want to write a <code>docker-compose.yml</code> for the above image. My understanding is that you can run multiple containers with docker-compose.</p>
  
  <p>So if i want to run 5 images of <code>docker-whale</code>, how does <code>docker-compose.yml</code> looks like?</p>