What is the difference between a Docker image and a Docker container?

The distinction between a Docker image and a Docker container is best captured by understanding that an image serves as a blueprint or template from which containers are created. An image contains everything needed to run an application, including the application code, libraries, dependencies, and environment settings. It remains unchanged and is essentially a static snapshot.

In contrast, a container is a live, running instance of that image. When a container is created, it utilizes the image but can also be modified and retains its own state during its lifecycle. This allows the application to be executed and interacted with actively, making containers dynamic as opposed to the static nature of images.

This concept highlights the relationship whereby multiple containers can be instantiated from the same Docker image, sharing the underlying structure while existing as separate execution environments. This distinction is fundamental for understanding Docker’s architecture and how it manages application deployment and scalability.