title: how to set ulimit / file descriptor on docker container the image tag is phusion/baseimage-docker
body: <p>I need to set the file descriptor limit correctly on the docker container 
  I connect to container with ssh (<a href="https://github.com/phusion/baseimage-docker" rel="noreferrer">https://github.com/phusion/baseimage-docker</a>)</p>
  
  <p>Already tried:</p>
  
  <ul>
  <li>edit limits.conf  the container ignore this file </li>
  <li>upstart procedure found at <a href="https://coderwall.com/p/myodcq" rel="noreferrer">https://coderwall.com/p/myodcq</a> but this docker image has different kind of init process. (runit)</li>
  <li>I tried to modify configuration of pam library in /etc/pam.d</li>
  <li>try to enabled pam for ssh  in sshd_config</li>
  </ul>
  
  <p>The output it always the same. </p>
  
  <pre><code>bash: ulimit: open files: cannot modify limit: Operation not permitted
  </code></pre>