anchor.diff:      rm bigdl*.zip
   
   # stage.3 bigdl-tutorials
  -FROM ubuntu:18.04
  +FROM ubuntu:20.04
   ARG BIGDL_VERSION
   ARG SPARK_VERSION
   ARG RUNTIME_SPARK_MASTER=local[4]
  
positive.code: ARG RUNTIME_EXECUTOR_CORES=4
  ARG RUNTIME_EXECUTOR_MEMORY=20g
  ARG RUNTIME_TOTAL_EXECUTOR_CORES=4
  ENV SPARK_VERSION                   ${SPARK_VERSION}
  ENV BIGDL_VERSION                   ${BIGDL_VERSION}
  ENV NOTEBOOK_PORT                   12345
  
negative.code:     fi
  
  # stage.2 bigdl
  FROM ubuntu:20.04 as bigdl
  ARG SPARK_VERSION
  ARG BIGDL_VERSION
  ARG DEBIAN_FRONTEND
  ENV SPARK_VERSION               ${SPARK_VERSION}
  ENV BIGDL_VERSION               ${BIGDL_VERSION}
  ENV BIGDL_HOME                  /opt/bigdl-${BIGDL_VERSION}
  