I learned about Docker as part of my evolving DevOps journey yet another technology revolutionizing the field of containerization. I explored the fundamentals through the DevOps Beginners to Advanced with Projects course on Udemy, and it was an eye-opener.
Why Docker?
Docker allows you to package applications and their dependencies into lean, portable containers. These containers can run anywhere locally, on virtual machines, or in the cloud ensuring consistent deployment across environments.
Docker forms the foundation of DevOps, microservices, and cloud-native development, so learning it early provides a significant advantage.
What I Learned
Throughout the course, we covered:
- Installing Docker on Linux
- Understanding images and containers
- Writing Dockerfiles
- Building and running custom containers
- Tagging and pushing images to Docker Hub
The learning was hands-on, beginner-friendly, and directly applicable to real-world DevOps workflows.
Docker Tips for Beginners
Here are some of the lessons and insights I picked up quickly:
1. Recognize the Distinction Between Containers and Images
- Images are templates.
- Containers are running instances of those templates.
Use docker ps to view running containers, and docker images to see your available images.
2. Understand the Dockerfile Fundamentals
Here’s a simple Dockerfile example:
FROM python:3.9-slim
WORKDIR /app
COPY . .
RUN pip install -r requirements.txt
CMD ["python", "app.py"]
3. Make Images Lightweight
Use slim or alpine base images when possible to reduce build size and enhance performance:
FROM node:18-alpine
4. Use .dockerignore
Prevent unnecessary files from being added to your image:
__pycache__/
*.log
.env
5. Tag and Push to Docker Hub
Use versioned tags instead of latest for better flexibility:
docker tag myapp:latest mydockerhub/myapp:v1.0
docker push mydockerhub/myapp:v1.0
What’s Next?
Now that I understand the basics, I intend to:
- Integrate Docker with Jenkins and Kubernetes
- Use Docker Compose for multi-container applications
- Optimize Dockerfiles for faster builds
- Develop a Dockerized project portfolio
Final Thoughts
Docker was one of the most exciting parts of the DevOps Beginners to Advanced with Projects course. It brought to life concepts like “build once, run anywhere,” and now I can containerize my own applications confidently.
More Dockerized projects will be posted on my portfolio site soon so stay tuned! And if you’re just getting started, here’s my course certificate that helped me build this foundation! Udemy Certificate.