anchor.diff:  
   # install dev tools
   RUN set -x \
  -    && apt-get update && apt-get install -y \
  +    && apt-get update && DEBIAN_FRONTEND=noninteractive apt-get install -y \
       curl tar sudo openssh-server openssh-client rsync unzip krb5-user
   
   # Kerberos client
  
positive.code:     && ssh-keygen -q -N "" -t rsa -f /etc/ssh/ssh_host_rsa_key \
      && ssh-keygen -q -N "" -t rsa -f /root/.ssh/id_rsa \
      && cp /root/.ssh/id_rsa.pub /root/.ssh/authorized_keys
  
  # java
  RUN set -x \
      && mkdir -p /usr/java/default \
      && curl -Ls 'https://download.oracle.com/otn-pub/java/jdk/8u251-b08/3d5a2bb8f8d4428bbe94aed7ec7ae784/jdk-8u251-linux-x64.tar.gz' -H 'Cookie: oraclelicense=accept-securebackup-cookie' | \
          tar --strip-components=1 -xz -C /usr/java/default/
  
  ENV JAVA_HOME /usr/java/default
  ENV PATH $PATH:$JAVA_HOME/bin
  
  RUN sed -i 's/^#crypto.policy=unlimited/crypto.policy=unlimited/' $JAVA_HOME/jre/lib/security/java.security
  
  
negative.code: #
  # Creates multi-node, kerberized Hadoop cluster on Docker
  
  FROM openjdk:8
  
  RUN set -x \
      && addgroup hadoop \
  