title: error starting docker daemon on ubuntu 14.04 (Devices cgroup isn't mounted)
body: <p>I followed docker instructions to install and verify the docker installation (from <a href="http://docs.docker.com/linux/step_one/">http://docs.docker.com/linux/step_one/</a>).</p>
  
  <p>I tried on 2 Ubuntu 14.04 machines and on both I got following error when starting docker daemon:</p>
  
  <pre><code>$ sudo docker daemon
  INFO[0000] Listening for HTTP on unix (/var/run/docker.sock) 
  INFO[0000] [graphdriver] using prior storage driver "aufs" 
  INFO[0000] Option DefaultDriver: bridge                 
  INFO[0000] Option DefaultNetwork: bridge                
  WARN[0000] Running modprobe bridge nf_nat br_netfilter failed with    message: modprobe: WARNING: Module br_netfilter not found. , error: exit status 1 
  INFO[0000] Firewalld running: false                     
  WARN[0000] Your kernel does not support cgroup memory limit: mountpoint for memory not found 
  WARN[0000] mountpoint for cpu not found                 
  FATA[0000] Error starting daemon: Devices cgroup isn't mounted 
  </code></pre>
  
  <p>I appreciate any help to resolve this issue.</p>