Issue link: https://insights.oneneck.com/i/1293607
CHAPTER 4 Preparing for and Testing Docker Containers 29 These materials are © 2017 John Wiley & Sons, Inc. Any dissemination, distribution, or unauthorized use is strictly prohibited. You don't want changes made to an image, but you do want to be able to interact with what's running inside, and that often means that you'll need a read/write file system to make that happen. When a container is started up, Docker adds a thin read/write layer on top of the image to handle this interaction. Figure 4-2 gives you a look at a running container with this addi- tional layer. FIGURE 4-1: A Docker image with four layers. FIGURE 4-2: A running Docker container.