title: Understanding the output of `docker-compose pull`
body: <p>When I run <code>docker-compose pull</code> for a project with a lot of services, I see output like this:</p>
  
  <pre><code>...
  Pulling service1     ... downloading (64.0%)
  Pulling service2     ... downloading (79.3%)
  Pulling service3     ... downloading (64.0%)  
  ...
  </code></pre>
  
  <p>The numbers seem to go up and down and sometimes they are being updated simultaneously for multiple services. What does this output mean and how to understand the actual progress of <code>docker-compose pull</code>?</p>