Disclaimer: The details in this post have been derived from various sources. If you find any inaccuracies or omissions, please leave a comment, and I will do my best to fix them.

Docker has revolutionized the way we build, share, and deploy applications. Whether you’re just starting with Docker or you’re looking for a quick reference, this guide will provide you with everything you need to know about Docker commands, best practices, and tips.

Table of Contents

  1. What is Docker?
  2. Key Docker Concepts
  3. Installing Docker
  4. Essential Docker Commands
  5. Working with Images
  6. Working with Containers
  7. Docker Networks
  8. Docker Volumes (Data Persistence)
  9. Docker Compose
  10. Best Practices
  11. Troubleshooting Commands
  12. Resources for Further Learning

What is Docker?

Docker is a platform for developing, shipping, and running applications inside lightweight, portable containers. These containers ensure consistency across different environments, making it easier to scale and deploy applications.

Key Docker Concepts

  • Image: A blueprint for containers, similar to a snapshot or template.
  • Container: A running instance of an image.
  • Dockerfile: A text file with instructions to build an image.
  • Registry: A repository to store and share Docker images (e.g., Docker Hub).
  • Volume: A mechanism to persist data generated or used by Docker containers.
  • Network: Allows containers to communicate with each other or with external systems.

Installing Docker

Install Docker by following the official documentation for your operating system:

Verify installation:

docker --version

Essential Docker Commands

Check Docker Installation

docker version  # Display Docker client and server versions
docker info     # Display system-wide information

Get Help

docker --help        # General help
docker <command> --help  # Help for a specific command

Working with Images

Search and Pull Images

docker search <image_name>   # Search for an image on Docker Hub
docker pull <image_name>     # Download an image

List Local Images

docker images

Remove an Image

docker rmi <image_name>

Build an Image

docker build -t <image_name>:<tag> .

Working with Containers

Run a Container

docker run -it <image_name>        # Interactive terminal
docker run -d <image_name>         # Detached mode
docker run -p 8080:80 <image_name> # Map host port 8080 to container port 80

List Running Containers

docker ps          # Running containers
docker ps -a       # All containers

Stop, Start, and Restart a Container

docker stop <container_id>
docker start <container_id>
docker restart <container_id>

Remove a Container

docker rm <container_id>

Execute Commands Inside a Container

docker exec -it <container_id> bash

Inspect a Container

docker inspect <container_id>

Docker Networks

List Networks

docker network ls

Create a New Network

docker network create <network_name>

Connect a Container to a Network

docker network connect <network_name> <container_name>

Disconnect a Container from a Network

docker network disconnect <network_name> <container_name>

Docker Volumes (Data Persistence)

Create a Volume

docker volume create <volume_name>

List Volumes

docker volume ls

Use a Volume

docker run -v <volume_name>:/path/in/container <image_name>

Remove a Volume

docker volume rm <volume_name>

Docker Compose

What is Docker Compose?

Docker Compose allows you to define and manage multi-container applications using a docker-compose.yml file.

Common Commands

docker-compose up         # Start services
docker-compose down       # Stop services
docker-compose build      # Build images
docker-compose ps         # List services

Example docker-compose.yml

version: '3'
services:
  web:
    image: nginx
    ports:
      - "8080:80"
  db:
    image: mysql
    environment:
      MYSQL_ROOT_PASSWORD: example

Best Practices

  1. Minimize Image Size: Use lightweight base images like alpine.
  2. Use Multi-Stage Builds: Optimize builds for production.
  3. Tag Images: Use meaningful tags for versioning (myapp:v1.0).
  4. Leverage .dockerignore: Exclude unnecessary files when building images.
  5. Keep Containers Stateless: Store persistent data in volumes.
  6. Monitor Containers: Use tools like docker stats or external monitoring tools.
  7. Regular Cleanup: Remove unused containers, images, and volumes (docker system prune).

Troubleshooting Commands

Check Logs

docker logs <container_id>

Debugging Containers

docker exec -it <container_id> bash

Inspect Networking

docker network inspect <network_name>

Prune Unused Resources

docker system prune -a

Resources for Further Learning

This blog post is your all-in-one Docker guide. Bookmark it, and keep it handy for your containerization journey! Happy Dockering!

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