Docker and Kubernetes Cheat Sheet

docker run -d --name web -p 8080:80 nginx:1.30-alpine
docker run -it --rm alpine:3.24 sh     # interactive, delete on exit
docker run -e KEY=value image          # environment variable
docker run --env-file .env image
docker run -v data:/var/lib/data image # volume
docker run -v "$PWD":/app image        # bind mount
docker run --network app-net image
docker run --restart unless-stopped image
docker run --memory=256m --cpus=1 image

docker ps                   # running
docker ps -a                # all
docker logs -f web          # follow logs
docker exec -it web sh      # shell inside
docker stop web             # SIGTERM, then SIGKILL
docker start web
docker restart web
docker rm -f web            # stop and remove
docker cp file web:/path    # copy a file
docker inspect web
docker stats                # live resource use

docker images
docker pull postgres:17-alpine
docker build -t app:1.0 .
docker build --target test -t app:test .
docker tag app:1.0 you/app:1.0
docker push you/app:1.0
docker rmi app:1.0
docker history app:1.0

FROM python:3.13-slim
ENV PYTHONUNBUFFERED=1
WORKDIR /app
COPY requirements.txt .
RUN pip install --no-cache-dir -r requirements.txt
COPY . .
USER nobody
EXPOSE 8000
HEALTHCHECK CMD curl -f http://localhost:8000/health
CMD ["gunicorn", "--bind", "0.0.0.0:8000", "app:app"]

FROM node:24-alpine AS build
WORKDIR /app
COPY package*.json ./
RUN npm ci
COPY . .
RUN npm run build

FROM nginx:1.30-alpine
COPY --from=build /app/dist /usr/share/nginx/html

docker volume ls
docker volume create data
docker volume rm data
docker network ls
docker network create app-net
docker network inspect app-net

services:
  api:
    build: .
    ports:
      - "8000:8000"
    environment:
      DATABASE_URL: postgres://app:pass@db:5432/app
    depends_on:
      db:
        condition: service_healthy
  db:
    image: postgres:17-alpine
    environment:
      POSTGRES_PASSWORD: pass
    volumes:
      - db-data:/var/lib/postgresql/data
    healthcheck:
      test: ["CMD-SHELL", "pg_isready"]
      interval: 5s
volumes:
  db-data:

docker compose up -d
docker compose up -d --build
docker compose ps
docker compose logs -f api
docker compose exec api sh
docker compose run --rm api npm test
docker compose down
docker compose down -v      # also delete volumes

docker container prune      # stopped containers
docker image prune -a       # unused images
docker volume prune         # unused volumes: careful
docker system df            # disk use
docker system prune         # most of the above

docker ps -a
docker logs name
docker inspect --format '{{.State.ExitCode}}' name
docker run -it --rm --entrypoint sh image

kubectl get pods,deploy,svc
kubectl apply -f app.yaml
kubectl delete -f app.yaml
kubectl describe pod name
kubectl logs -f name
kubectl logs --previous name
kubectl exec -it name -- sh
kubectl scale deployment web --replicas=3
kubectl set image deployment/web c=app:2.0
kubectl rollout status deployment/web
kubectl rollout undo deployment/web
kubectl port-forward service/web 8080:80
kubectl get events --sort-by=.lastTimestamp