anchor.diff:  
   EXPOSE 12000
   
  -CMD ["sqoop2-server", "start"]
  +CMD sqoop2-server start && tail -f $SQOOP_HOME/@LOGDIR@/sqoop.log
  
positive.code: 
  MAINTAINER Jiayu Liu <etareduce@gmail.com>
  
  ENV SQOOP_HOME /usr/lib/sqoop
  ENV SQOOP_VERSION 1.99.7
  
  # choose a closer mirror
  RUN mkdir -p $SQOOP_HOME \
  
negative.code:     && curl -o /tmp/sqoop-$SQOOP_VERSION-bin-hadoop200.tar.gz https://mirrors.tuna.tsinghua.edu.cn/apache/sqoop/$SQOOP_VERSION/sqoop-$SQOOP_VERSION-bin-hadoop200.tar.gz \
      && tar -xvf /tmp/sqoop-$SQOOP_VERSION-bin-hadoop200.tar.gz -C $SQOOP_HOME --strip-components=1 \
      && rm /tmp/sqoop-$SQOOP_VERSION-bin-hadoop200.tar.gz
  
  # override the core-site
  ADD core-site.xml $HADOOP_HOME/etc/hadoop/core-site.xml
  