containers.yml

macros:
 get_release:  # In the end of the docker build print version of the installed GCC 
  - cat /etc/*release
  - gcc --version

 build_essential_centos: # Install GCC&friends
  - gcc 
  - gcc-c++ 
  - make
 
 make_dir:
  - mkdir -p /etc/docker
 
 environment_vars:
   # I need an env variable referencing a persistent folder
   - SHARED_FOLDER /etc/docker  

dockerfiles:

 centos7:
    base: centos:centos7
    packager: rpm
    help_disable: false  # optional flags controlling the Dockerfile L&F 
    readme_disable: false
    build_trace_disable: false
    comments_disable: false
    
    install:
      - $build_essential_centos 
      - rpm-build
    run:
      - $get_release
    env:
      - $environment_vars

 ubuntu.16.04:
    packager: deb
    stages:
      - intermediate: # Comment for intermediate 
         base: ubuntu:16.04
         help: 
           - Intermediate container help
         sections:
           - section:  #first section
             expose:
               - 8080/TCP
             install:
               - build-essential    
           - section: # second section
             run:
               - $get_release
             env:
               - $environment_vars
      - final: # Comment for final
         base: intermediate
         help: 
           - Final container help
         run:
           - touch "/root/final"
           - echo "Final"