5 Steps to Become a Full-Stack Developer

Deploying a Docker App on Oracle Cloud Free Tier (1GB VM)

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A Complete Step-by-Step Guide (FastAPI + Docker + Selenium)

If you’re building side projects, automation tools, or learning cloud deployment, Oracle Cloud’s free tier VM is one of the best places to start.

In this guide, I’ll walk you through how I deployed a Dockerized FastAPI + Selenium app on a 1GB RAM VM, optimized it to avoid crashes, and made it production-ready.

📌 Why This Guide Matters

A 1GB VM is very limited. Without proper setup, you may face:

  • App crashes
  • Docker failures
  • Selenium memory errors
  • Unresponsive server

This guide includes all fixes we learned the hard way 😄

🧱 Step 1 — Create VM (Oracle Cloud)

  1. Go to Oracle Cloud Console
  2. Click Create Instance
  3. Use the following configuration:
  • Shape: VM.Standard.E2.1.Micro
  • CPU: 1 OCPU
  • Memory: 1 GB
  • Boot Volume: 100 GB
  • OS: Ubuntu 22.04

👉 Add your SSH public key during creation

🔐 Step 2 — SSH into VM

chmod 600 your-key.pem
ssh -i your-key.key ubuntu@<PUBLIC_IP>

🔄 Step 3 — Update System

sudo apt update && sudo apt upgrade -y

If you see a kernel update message:

sudo reboot

Reconnect after reboot.

💾 Step 4 — Create Swap (VERY IMPORTANT)

A 1GB VM is not enough for Docker + Selenium.

Create a 2GB swap file:

sudo fallocate -l 2G /swapfile
sudo chmod 600 /swapfile
sudo mkswap /swapfile
sudo swapon /swapfile

Make it permanent:

echo '/swapfile none swap sw 0 0' | sudo tee -a /etc/fstab

Verify:

free -h

👉 This prevents your app from crashing due to low memory.

🐳 Step 5 — Install Docker

sudo apt install -y docker.io

Enable Docker:

sudo systemctl start docker
sudo systemctl enable docker

Allow non-root usage:

sudo usermod -aG docker $USER

Reconnect:

exit
ssh -i your-key.pem ubuntu@<PUBLIC_IP>

Verify:

docker --version

🔓 Step 6 — Open Required Ports

Oracle Cloud Security List

Add ingress rule:

  • Source: 0.0.0.0/0
  • Protocol: TCP
  • Port: 8001

Ubuntu Firewall

sudo ufw allow 8001
sudo ufw enable

🔑 Step 7 — Setup GitHub SSH

Generate key:

ssh-keygen -t ed25519 -C "your-email"

Start agent:

eval "$(ssh-agent -s)"
ssh-add ~/.ssh/id_ed25519

Copy public key:

cat ~/.ssh/id_ed25519.pub

Add it to GitHub → Settings → SSH Keys

Test connection:

ssh -T [email protected]

📦 Step 8 — Clone Repository

git clone [email protected]:<your-username>/<repo>.git
cd <repo>

🏗️ Step 9 — Build Docker Image

docker build -t epay-auto:1.0 .

▶️ Step 10 — Run Container

docker run -d \
  --name epay-auto \
  -p 8001:8001 \
  --shm-size=1g \
  epay-auto:1.0

👉 --shm-size=1g is critical for Selenium stability

🌐 Step 11 — Access Your App

http://<PUBLIC_IP>:8001

⚠️ Note: This is HTTP, not HTTPS

🔍 Step 12 — Check Logs

docker logs -f epay-auto

🔄 Step 13 — Update Deployment

After making code changes:

cd <repo>
git pull

Stop old container:

docker stop epay-auto
docker rm epay-auto

(Optional) remove old image:

docker rmi epay-auto:1.0

Rebuild:

docker build --no-cache -t epay-auto:1.1 .

Run again:

docker run -d \
  --name epay-auto \
  -p 8001:8001 \
  --shm-size=1g \
  epay-auto:1.1

🔁 Step 14 — Versioning & Rollback

Using version tags helps you roll back if something breaks.

Rollback Example

docker stop epay-auto
docker rm epay-auto

# Run previous version
docker run -d \
  --name epay-auto \
  -p 8001:8001 \
  --shm-size=1g \
  epay-auto:1.0

🧹 Step 15 — Cleanup Disk Space

Check usage:

docker system df

Remove unused data:

docker system prune -a

⚡ Troubleshooting

App not accessible

docker ps
sudo ss -tulnp | grep 8001

Check:

  • OCI security rules
  • Firewall (ufw)

App crashes

Ensure:

  • Swap is enabled
  • --shm-size=1g is set

Old code still showing

docker build --no-cache -t epay-auto:1.1 .

GitHub SSH issue

If you see:

Permission denied (publickey)

Make sure:

  • SSH key is added to GitHub
  • SSH agent is running

🧠 Key Learnings

  • Always add swap for low-memory VMs
  • Selenium requires shared memory (--shm-size)
  • OCI security rules are mandatory
  • Use Docker tags for safe deployments
  • Always rebuild with --no-cache when debugging

🎯 Final Architecture

User → Public IP → OCI Firewall → VM → Docker → FastAPI
                                      → Selenium

🚀 Conclusion

With proper setup, even a free 1GB VM can run a production-ready Docker app smoothly.

This setup is perfect for:

  • Side projects
  • Automation tools
  • Learning DevOps
  • Portfolio projects

✨ Next Improvements

  • Add HTTPS (Nginx + SSL)
  • Use Docker Compose
  • Add CI/CD pipeline
  • Use domain instead of IP

If this helped you, feel free to share or connect!

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