Glossary term
What is container? Meaning for developers
In DevOps
A running instance of a Docker image: your app in an isolated box that shares the host's kernel. Starts in under a second.
Learn it properly · DevOpsLesson 9: Docker: Containerize Your Next.js and Node AppImages, layers, Dockerfiles and Compose — build once, run the same thing on your laptop and on EC2.In System Design
A lightweight, isolated package of an app and its dependencies. Example: The same image runs on a laptop and in production.
Learn it properly · System DesignLesson 55: Docker & Containers for Beginners“It works on my machine” ends here. What containers really are (and aren't), images, layers and registries, a production-grade multi-stage Dockerfile, running and composing containers locally, tags vs digests, and the security basics.In Docker & Kubernetes
A normal process that the Linux kernel isolates with namespaces and limits with cgroups, running from an image.
Learn it properly · Docker & KubernetesLesson 0: Why Containers: Images, Containers and How They Differ From VMsThe problem containers solve, namespaces and cgroups in plain words, images versus containers, registries, and the first docker run.