title: Why my Docker container's writable layer persists after the container exits?
body: <p>Docker's <a href="https://docs.docker.com/storage/" rel="nofollow noreferrer">storage overview</a> documentation says:</p>
  
  <blockquote>
    <ul>
    <li><strong>The data doesn’t persist when that container is no longer running</strong>, and it can be difficult to get the data out of the container if another process needs it.</li>
    <li>A container’s writable layer is tightly coupled to the host machine where the container is running. You can’t easily move the data somewhere else.</li>
    <li>Writing into a container’s writable layer requires a storage driver to manage the filesystem. The storage driver provides a union filesystem, using the Linux kernel. This extra abstraction reduces performance as compared to using data volumes, which write directly to the host filesystem.</li>
    </ul>
  </blockquote>
  
  <p>As you can see, the docs say, "The data doesn’t persist when that container is no longer running". So why isn't the data removed when I stop my container?</p>
  
  <p><img src="https://i.stack.imgur.com/zmXrc.png" alt="Action logs"></p>