title: Reuse host binaries or share between containers in Docker
body: <p>Consider the following scenario:</p>
  
  <p>There are three independent web applications A, B and C that require an apache server to be run on. </p>
  
  <p>A linux server runs web application A and may act as a Docker host. It is required that the applications B and C are isolated from the linux server and each other. They are therefore realized as two Docker containers, initially created from the same image.</p>
  
  <p>My question updates, and security updates in special.</p>
  
  <p>Do the two Docker containers require a full OS installation image? Can they share the host's apache binary, so security updates of the host's apache could be propagated to the containers automatically?</p>
  
  <p>If this doesn't work: Would I need to install updates for apache on both containers independently, or could I benefit from the fact, that they are based on the same image, and somehow simplify the update process?</p>