• Build the Docker Image
  • docker build -t express-app:local .
  • docker run -d -p 3000:3000 --name express-test express-app:local
• View Logs (Optional)
• docker logs -f express-test
• Stop & Clean Up (Optional)
• docker stop express-test
• docker rm express-test

GitLab CI/CD Secrets to Set

In GitLab > Project > Settings > CI/CD > Variables, add:

Key	Value

DOCKER_USERNAME =>	Your Docker Hub username
DOCKER_PASSWORD =>	Your Docker Hub password/token
EC2_HOST =>	user@your-ec2-public-ip
EC2_KEY =>	Paste your private SSH key
DOCKER_IMAGE_NAME => username/repo-name

EC2 Instance Setup (One-Time Manual)

• SSH into your EC2 instance:

sudo apt update
sudo apt install -y docker.io
sudo usermod -aG docker ubuntu
newgrp docker

• Also allow port 80 in the EC2 security group.

Test It

• Commit & push to the master branch.
• GitLab will build the Docker image and push it to Docker Hub.
• GitLab will SSH into EC2 and deploy the container.