title: Pull docker images from a private repository during docker build?
body: <p>Is there any way of pulling images from a private registry during a <code>docker build</code> instead of docker hub?</p>
  
  <p>I deployed a private registry and I would like to be able to avoid naming its specific <code>ip:port</code> in the Dockerfile's <code>FROM</code> instruction. I was expecting a <code>docker build</code> option or a docker environment variable to change the default registry.</p>