message: Use docker multi-stage build to reduce the docker image size
diff: - FROM centos:7
  + FROM centos:7 as builder
  LABEL maintainer="SvenDowideit@home.org.au, zhangshaomin_1990@126.com"
  @@ -34,7 +34,16 @@ RUN rpm -ivh https://mirrors.aliyun.com/epel/epel-release-latest-7.noarch.rpm &&
  yum -y remove git && \
  yum -y clean all
  +FROM centos:7
  +ENV PIKA /pika
  +ENV PATH ${PIKA}:${PIKA}/bin:${PATH}
  +
  +RUN set -eux; yum install -y epel-release; \
  + yum install -y snappy protobuf gflags glog bzip2 zlib lz4 libzstd rsync; \
  + yum clean all;
  +
  WORKDIR ${PIKA}
  +COPY --from=builder $PIKA ./
  ENTRYPOINT ["/pika/entrypoint.sh"]
  CMD ["/pika/bin/pika", "-c", "/pika/conf/pika.conf"]
  