title: Docker practice for CI/CD and deployment
body: <p>I'm new to Docker and read some articles about it. </p>
  
  <p>I read many articles that say "use same image for all environments(dev/stage/production)" and "image for CI/CD and for deployment are different".</p>
  
  <p>But I can't integrate those two advices and I also can't find dockerfile examples for that.</p>
  
  <p>Is that mean I have to make below two docker images? </p>
  
  <pre><code>(1) image for deployment
  - application code and its dependencies
  - there is no CMD 
  
  (2) image for CI/CD
  - use (1) as base image
  - add extra for CI/CD
  </code></pre>