Docker And Docker Compose Cheatsheet

### Docker and Docker Compose Cheatsheet

Docker Commands

1. Docker Basics

   • docker --version: Check Docker version.
   • docker info: Display system-wide information.

2. Images

   • docker images: List all images.
   • docker pull <image>: Download an image from a registry.
   • docker build -t <name>:<tag> .: Build an image from a Dockerfile in the current directory.
   • docker rmi <image>: Remove an image.

3. Containers

   • docker ps: List running containers.
   • docker ps -a: List all containers.
   • docker run -it <image>: Run a container interactively.
   • docker run -d <image>: Run a container in detached mode.
   • docker run -p <host_port>:<container_port> <image>: Run a container with port mapping.
   • docker stop <container>: Stop a running container.
   • docker start <container>: Start a stopped container.
   • docker restart <container>: Restart a container.
   • docker rm <container>: Remove a stopped container.
   • docker logs <container>: View container logs.
   • docker exec -it <container> <command>: Execute a command inside a running container.

4. Volumes

   • docker volume create <volume>: Create a volume.
   • docker volume ls: List all volumes.
   • docker volume rm <volume>: Remove a volume.
   • docker run -v <volume>:/path/in/container <image>: Run a container with a volume.

5. Networks

   • docker network create <network>: Create a network.
   • docker network ls: List all networks.
   • docker network rm <network>: Remove a network.
   • docker run --network <network> <image>: Run a container on a network.

Dockerfile Instructions

1. Basic Instructions

   • FROM <image>: Set the base image.
   • RUN <command>: Execute a command during the build process.
   • COPY <src> <dest>: Copy files/directories to the image.
   • ADD <src> <dest>: Similar to COPY, but can also extract TAR files and download URLs.
   • WORKDIR <path>: Set the working directory.
   • CMD ["executable", "param1", "param2"]: Set the default command to run.
   • ENTRYPOINT ["executable", "param1", "param2"]: Configure a container to run as an executable.
   • EXPOSE <port>: Expose a port.
   • ENV <key>=<value>: Set an environment variable.

2. Advanced Instructions

   • ARG <name>: Define a build-time variable.
   • LABEL <key>=<value>: Add metadata to the image.
   • ONBUILD <instruction>: Add a trigger instruction for the next build stage.
   • HEALTHCHECK <options> CMD <command>: Check container health.

Docker Compose Commands

1. Basics

   • docker-compose --version: Check Docker Compose version.
   • docker-compose up: Create and start containers.
   • docker-compose up -d: Start containers in detached mode.
   • docker-compose down: Stop and remove containers, networks, images, and volumes.
   • docker-compose ps: List containers.
   • docker-compose logs: View logs of all containers.
   • docker-compose logs <service>: View logs of a specific service.
   • docker-compose exec <service> <command>: Execute a command in a running container.
   • docker-compose build: Build or rebuild services.
   • docker-compose stop: Stop running containers.
   • docker-compose start: Start existing containers.
   • docker-compose restart: Restart containers.

2. Docker Compose File (docker-compose.yml) Structure

   version: '3.8'
   
   services:
     app:
       image: node:14
       build:
         context: .
         dockerfile: Dockerfile
       ports:
         - "3000:3000"
       environment:
         - NODE_ENV=development
       volumes:
         - .:/usr/src/app
         - /usr/src/app/node_modules
       depends_on:
         - mongo
   
     mongo:
       image: mongo:4.4
       ports:
         - "27017:27017"
       volumes:
         - mongo-data:/data/db
   
   volumes:
     mongo-data:

3. Common Service Configuration Options

   • build: Configuration options for the build (context, dockerfile, args).
   • image: Specify an image to use.
   • command: Override the default command.
   • ports: Map ports from the host to the container.
   • volumes: Mount host paths or named volumes.
   • environment: Set environment variables.
   • depends_on: Specify service dependencies.
   • networks: Connect services to specific networks.
   • restart: Define the restart policy (no, always, on-failure, unless-stopped).

Examples

1. Simple Node.js Application with MongoDB

Dockerfile:

# Dockerfile
FROM node:14

WORKDIR /usr/src/app

COPY package*.json ./
RUN npm install

COPY . .

EXPOSE 3000
CMD ["npx", "babel-node", "src/index.js"]

docker-compose.yml:

version: '3.8'

services:
  app:
    build: .
    ports:
      - "3000:3000"
    env_file:
      - .env
    volumes:
      - .:/usr/src/app
      - /usr/src/app/node_modules
    depends_on:
      - mongo

  mongo:
    image: mongo:4.4
    ports:
      - "27017:27017"
    volumes:
      - mongo-data:/data/db

volumes:
  mongo-data:

.env:

PORT=3000
MONGODB_URL=mongodb://mongo:27017/mydatabase

Conclusion

This cheatsheet provides a quick reference for essential Docker and Docker Compose commands and configurations. Whether you're building, running, or managing containers, these commands and instructions will help streamline your development and deployment workflows.