Like other metaphorical objects that float on the water, Docker has a lot hidden below its surface. Many of us use Docker or other containerization platforms to run our applications. But what are containers and images, and how do these two concepts come together in Docker?
In this talk we'll build a simple image and start a running container from it. Then, like the curious engineers we are, we'll start poking and prodding this container and its image to learn what's actually going on under the hood.
We'll see how Linux namespaces and cgroups are used to lie to the running container process about its networking and filesystem environment and its available resources. We'll see how the overlay filesystem is used to stack the layers of the image up into what the container sees as a unified file system. And we'll see how the image is stored as a simple collection of tarballs and json files.
Finally, we'll look at other ways to build images, and see what's different about the resulting images and containers.
