content: ########## How To Use Docker Image ###############
  ##
  ##  Install docker utility
  ##  Download docker image: docker pull denny/hadoop:v1
  ##  Boot docker container:
  ##     docker run -d -t -h myhadoopaio --name my-hadoop-aio --privileged -v /root/ -p 15022:22 -p 8088:8088 -p 9000:9000 -p 50000-50100:50000-50100 -p 19888:19888 denny/hadoop:v1 /usr/sbin/sshd -D
  ##
  ##  Start services:
  ##     docker start my-hadoop-aio
  ##     docker exec -it my-hadoop-aio bash
  ##
  ##     bash /usr/local/hadoop/sbin/stop-dfs.sh
  ##     bash /usr/local/hadoop/sbin/stop-yarn.sh
  ##
  ##     bash /usr/local/hadoop/sbin/start-dfs.sh
  ##     bash /usr/local/hadoop/sbin/start-yarn.sh
  ##
  ##     jps
  ##
  ##     Ports:
  ##        sshd 22,
  ##        ResourceManager: 8088, 8031, 8030, 8032, 8033
  ##        NameNode: 50070, localhost:9000
  ##        SecondaryNameNode: 50090
  ##        DataNode: 50010, 50075, 50020
  ##        NodeManager: 58095, 8040, 13562, 8042
  ##        
  ##     http endpoints:
  ##       NameNode: http://hadoop_ip:50070
  ##       ResourceManager: http://hadoop_ip:8088
  ##       MapReduce JobHistory Server: http://hadoop_ip:19888
  ##       SecondaryNameNode: http://hadoop_ip:50090
  ##################################################
  
  FROM ubuntu:14.04
  MAINTAINER DennyZhang.com <http://dennyzhang.com>
  
  ########################################################################################
  
  # TODO: install packages
  apt-get install -y curl tree
  
  apt-get -y update
  
  # clean up
  rm -rf /var/cache/*
  rm -rf /tmp/* /var/tmp/*
  rm -rf /usr/share/doc && \
  apt-get clean && apt-get autoclean
  ########################################################################################
  