content: ########## How To Use Docker Image ###############
  ##
  ##  Install docker utility
  ##  Download docker image: docker pull denny/chefserver:v1
  ##  Boot docker container: docker run -d -p 61080:80 -p 443:443 -p 61022:22 -h chefserver --name my-chefserver --privileged denny/chefserver:v1 /usr/sbin/sshd -D
  ##  Start container:
  ##    sysctl -w kernel.shmmax=17179869184
  ##    # change back hostname
  ##    echo "127.0.0.1 chefserver" >> /etc/hosts
  ##    nohup /opt/opscode/embedded/bin/runsvdir-start &
  ##    chef-server-ctl stop
  ##    chef-server-ctl start
  ##    chef-server-ctl status
  ##    chef-server-ctl tail
  ##    chef-server-ctl reconfigure
  ##    ls -lth /var/log/opscode
  ##    curl -k -v http://127.0.0.1:443
  ##
  ##    In client node, download admin.pem and digitalocean-validator.pem
  ##    create knife.rb, say ~/.chef/my-chef-knife.rb
  ##    knife cookbook list -c ~/.chef/my-chef-knife.rb 
  ##################################################
  
  FROM denny/sshd:v1
  MAINTAINER DennyZhang.com <http://dennyzhang.com>
  
  ########################################################################################
  apt-get update
  wget --no-check-certificate https://web-dl.packagecloud.io/chef/stable/packages/ubuntu/*/chef-server-core_12.0.7-1_amd64.deb
  dpkg -i ./chef-server-core_12.0.7-1_amd64.deb
  /opt/opscode/embedded/bin/runsvdir-start &
  chef-server-ctl reconfigure
  chef-server-ctl status 
  
  # clean up
  rm -rf /var/cache/*
  rm -rf /tmp/* /var/tmp/*
  rm -rf /usr/share/doc && \
  apt-get clean && apt-get autoclean
  ########################################################################################
  