What is a Docker container?

A Docker container is inherently defined as a lightweight, stand-alone, executable package that encapsulates an application and its dependencies in a unified environment. This allows the application to run consistently across different computing environments. Containers are based on a shared operating system kernel, which contrasts with virtual machines that require a full OS for each instance. This shared architecture makes containers more efficient in terms of resource usage and faster to start compared to virtual machines.

The key characteristic of being lightweight is essential because it means containers consume less overhead than traditional virtual machines. This efficiency enables developers to deploy applications quickly, scale them effortlessly, and maintain environments with consistent configurations.

While options referring to managing application dependencies or compressed archives of files touch on specific uses or aspects of Docker containers, they do not capture the complete essence of what a Docker container fundamentally represents. Additionally, characterizing a container as a virtual machine overlooks the core difference in how containers leverage the host operating system, providing a more agile and resource-efficient approach to application deployment.