anchor.diff:      fi
   
   # stage.2 bigdl
  -FROM ubuntu:18.04 as 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}
  
positive.code: ARG JDK_VERSION=8u192
  ARG JDK_URL=your_jdk_url
  ARG BIGDL_VERSION=0.14.0-SNAPSHOT
  
  # stage.1 jdk & spark
  FROM ubuntu:18.04 as spark
  ARG SPARK_VERSION
  ARG JDK_VERSION
  ARG JDK_URL
  ARG SPARK_HOME
  ENV SPARK_VERSION                       ${SPARK_VERSION}
  ENV SPARK_HOME                          ${SPARK_HOME}
  RUN apt-get update --fix-missing && \
  
negative.code: ARG RUNTIME_EXECUTOR_CORES=4
  ARG RUNTIME_EXECUTOR_MEMORY=20g
  ARG RUNTIME_TOTAL_EXECUTOR_CORES=4
  ARG DEBIAN_FRONTEND
  ENV SPARK_VERSION                   ${SPARK_VERSION}
  ENV BIGDL_VERSION                   ${BIGDL_VERSION}
  ENV NOTEBOOK_PORT                   12345
  