Container

A lightweight, stand-alone, executable package of software that includes everything needed to run a piece of software, including the code, runtime, libraries, and system settings.

A container is a lightweight, portable unit of software that packages application code together with its dependencies, libraries, and runtime environment. Unlike virtual machines, containers share the host operating system's kernel, making them faster to start and more resource-efficient.

Docker is the most widely used container runtime, and container images are typically stored in registries like Docker Hub or cloud-provider registries. Containers are defined by a Dockerfile or similar configuration that specifies the base image, dependencies, and startup commands.

Containers are foundational to microservices architectures, where each service runs in its own container and communicates with others via APIs. Container orchestration platforms like Kubernetes manage the deployment, scaling, and networking of containerized applications. While serverless platforms eliminate the need to manage containers directly, many serverless runtimes (including some configurations of Cloudflare Workers) use container-like isolation under the hood.