参考教程：https://docs.docker.com/develop/develop-images/dockerfile_best-practices/
环境
- virtual box 6.1
- centos 7.8
- docker 19.03
CMD
The CMD instruction should be used to run the software contained in your image, along with any arguments. CMD should almost always be used in the form of CMD ["executable", "param1", "param2"…]. Thus, if the image is for a service, such as Apache and Rails, you would run something like CMD ["apache2","-DFOREGROUND"]. Indeed, this form of the instruction is recommended for any service-based image.
应该使用 CMD 指令来运行镜像中包含的软件以及所有参数。CMD 几乎应始终以 CMD ["executable", "param1", "param2"…] 的形式使用。因此，如果镜像用于服务，例如 Apache 和 Rails，则将运行诸如 CMD ["apache2","-DFOREGROUND"]之类的内容。实际上，建议将这种形式的指令用于任何基于服务的镜像。
In most other cases, CMD should be given an interactive shell, such as bash, python and perl. For example, CMD ["perl", "-de0"], CMD ["python"], or CMD ["php", "-a"]. Using this form means that when you execute something like docker run -it python, you’ll get dropped into a usable shell, ready to go. CMD should rarely be used in the manner of CMD ["param", "param"] in conjunction with ENTRYPOINT, unless you and your expected users are already quite familiar with how ENTRYPOINT works.
在大多数其他情况下，应该给 CMD 一个交互式外壳，例如 bash，python 和 perl。例如，CMD ["perl", "-de0"]，CMD ["python"] 或 CMD ["php", "-a"]。使用此种格式意味着执行 docker run -it python 之类的操作时，您将进入可用的 shell 中，随时可以使用。除非您和您的预期用户已经非常熟悉 ENTRYPOINT 的工作原理，否则 CMD 很少以 CMD ["param", "param"] 的形式与 ENTRYPOINT 结合使用。
总结
介绍了 Dockerfile 的 CMD 指令的最佳实践。