What is Docker Hub?
Answer
Docker Hub is Docker's official cloud-based registry service — the world's largest library of container images. It is the default registry Docker uses when you docker pull an image without specifying a registry. Docker Hub hosts: (1) Official images: curated, security-scanned images for popular software maintained by Docker or the software vendor — nginx, mysql, node, python, ubuntu. Use these as base images; (2) Verified publisher images: images from certified companies (AWS, Oracle, etc.); (3) Community images: images published by individuals and organizations. Image naming convention: official images have no prefix (nginx:1.25); user/organization images have a username prefix (username/myapp:latest). Limits: Docker Hub free tier has pull rate limits (100 pulls/6 hours anonymously, 200 authenticated). For production or CI, use a private registry (Amazon ECR, Google GCR, GitHub Container Registry, self-hosted Harbor) or pay for Docker Hub Pro. Commands: docker login — authenticate; docker push username/myapp:1.0 — push your image; docker search nginx — search for images.