Day191-198 Hands-On Docker: From Basics to Real-World Deployment (Course Completed)

📚 The Start of Recording TIL Summer ‘24 : Why Did I Start This Project? 🚀

🔔 Don't Miss: Continous Records of TIL '25 (Still On-Going!) 🌟

✨ A New Chapter in TIL '25: Reflecting, Growing, and Moving Forward 📖

Docker Review — From CLI Fundamentals to Multi-Container Orchestration

Over the past week, I completed the course Hands-On Docker: From Basics to Real-World Deployment. While I’ve used Docker casually before, this time I focused on end-to-end container workflows — from basic CLI commands to deploying multi-container services on AWS EC2 — and documented every step in my Notion.

Throughout this intensive week, I felt a sense of empowerment and clarity as I moved from a scattered understanding of Docker to a confident, organized view. The course’s practical approach—from CLI commands to multi-container orchestration and cloud deployment—transformed my use of Docker into a structured, workflow-focused skill. I appreciated how smoothly the course explained everything! (from concepts like volumes and custom images to their integration in docker-compose.yml, which made managing complex stacks natural and empowering) Deploying to AWS EC2 was a “lightbulb” moment, highlighting Docker’s portability and boosting my confidence in its practical use.

Here’s what I learned and practiced hands-on.

Section 2–3: Docker CLI & Container Lifecycle

• Listed, created, started, stopped, and removed containers with docker create, docker run, docker ps, docker stop, docker rm
• Understood foreground vs. background execution modes and when to use each
• Mapped host ports to container ports with -p host:container for service access
• Used --name for easier container management instead of container IDs
• Checked container logs (docker logs -f --tail) and connected inside running containers with docker exec -it
• Use case: Running Nginx in the background with docker run -d -p 4000:80 nginx and instantly testing from the host browser.

Section 4: Volumes & Data Persistence

• Created named volumes to persist container data beyond container lifecycle
• Used bind mounts to sync local development files into containers
• Verified volume mounts in docker inspect
• Use case: Preserving MySQL data between container restarts for local development and testing.

Section 5: Building Custom Images

• Wrote Dockerfile to package a Spring Boot JAR into a container
• Understood build context, image layers, and caching for optimization
• Use case: Created a reusable Spring Boot image for deployment across multiple environments.

Section 6–7: Docker Compose for Multi-Container Management

• Defined multiple services (Spring Boot + MySQL, later adding Redis) in docker-compose.yml
• Used service names as hostnames for container-to-container communication (instead of localhost)
• Configured depends_on with healthcheck to ensure service readiness before startup
• Managed full-stack environments with a single command: docker compose up -d --build
• Use case: Built and ran Spring Boot + MySQL + Redis stack with persistent storage, port mapping, and service dependencies.

Section 8–9: Deploying to AWS EC2

• Installed Docker & Docker Compose on EC2
• Deployed multi-container apps to the cloud using the same local docker-compose.yml
• Verified external accessibility via public EC2 IP + exposed ports
• Use case: Hosting my Spring Boot app with MySQL backend on AWS for remote testing.

Key Lessons Learned

• Containers are isolated environments — localhost inside a container refers only to itself.
• Use service names for inter-container communication in Compose.
• Volumes are essential for persistent, stateful services.
• Health checks improve reliability in multi-service setups.
• One Compose file can define an entire application stack from local dev to production.

📒 My Docker Notes

I compiled all commands, configurations, and troubleshooting steps in Notion for quick reference:

🔗 Docker Study Notes: Visit Here!

These notes include:

• CLI command cheatsheets
• Example Dockerfile and docker-compose.yml setups
• Port mapping & volume management tips
• Debugging container networking issues
  

Examples are provided below…