Docker Hub — Image Registry

Docker Hub is the public Docker image registry. Think of it as npm for Node.js or PyPI for Python, but for containers.

What’s Available

• Official language images: python, node, golang, ruby
• Databases: postgres, mysql, mongodb, redis
• Web servers: nginx, apache
• Operating systems: ubuntu, debian, alpine

100+ million images. Official images are marked with a checkmark ✓ and have no username prefix in their name.

Image Name Structure

[username/]repository[:tag]

python              # official Python, latest tag
python:3.11         # Python 3.11
python:3.11-slim    # lightweight variant
python:3.11-alpine  # Alpine Linux based (smallest)
myuser/myapp:v1.0   # your own image

Tags:
- latest — most recent version (default)
- slim — fewer packages, smaller size
- alpine — Alpine Linux based (~5 MB base), most compact
- Specific version: 3.11, 3.11.2

Always pin a specific tag in production — latest can break your build on update.

Commands

docker search python             # search for images
docker pull python:3.11          # pull an image
docker tag myapp:latest myuser/myapp:v1.0  # tag an image
docker push myuser/myapp:v1.0    # publish
docker login                     # authenticate

Publishing Your Own Image

1. Create an account at hub.docker.com
2. Log in: docker login
3. Tag the image: docker tag myapp username/myapp:v1.0
4. Push: docker push username/myapp:v1.0

Free account: unlimited public repositories, 1 private.

Rate Limits

Anonymous users: 100 pulls per 6 hours. Authenticated users: 200 pulls per 6 hours. For CI/CD, use docker login with an access token.