How does Docker utilize overlay filesystems?

Docker uses overlay filesystems primarily to manage and layer filesystem changes efficiently for images and containers. This layering approach allows Docker to efficiently share common files among different images and containers, minimizing redundancy and optimizing storage.

When a Docker image is created, it consists of multiple layers. Each layer represents a set of filesystem changes over the previous layer. The overlay filesystem provides a mechanism to combine these layers into a single unified view for the container. This means that when a container is run, it can only see and interact with the top layer of this stack, which allows for isolation and efficient file management. Changes made by processes running inside the container are recorded in a new top layer without modifying the underlying image layers. This not only saves space but also allows for quick creation and deletion of containers from those images.

Additionally, using overlay filesystems is advantageous because it facilitates faster image builds and changes, as Docker only needs to process and store the differences between layers instead of duplicating entire filesystem structures.

Other options, while they touch on relevant concepts, do not capture the primary role of overlay filesystems in Docker. For example, compression of image sizes, backing up container data, and enhancing security are important considerations in the container ecosystem, but they do not directly explain the