Spring Boot Deployment

Deploying a Spring Boot app means packaging it and running it on a server or cloud platform. Spring Boot's embedded server makes this straightforward — the app ships as a single file that runs anywhere Java is installed.

Packaging Options

Package Type    Contents                          How to Run
────────────    ────────────────────────────────  ────────────────────────────
JAR (default)   App code + all dependencies       java -jar app.jar
                + embedded Tomcat

WAR             App code only (no Tomcat)         Deploy to external Tomcat
                                                  (legacy approach)

Use JAR for almost all modern deployments. The fat JAR contains everything — no external dependencies to install on the server.

Building the JAR

# Using Maven
mvn clean package

# The output file appears at:
target/demo-0.0.1-SNAPSHOT.jar

# Skip tests to build faster during deployment pipelines
mvn clean package -DskipTests

Running the JAR

# Basic run
java -jar target/demo-0.0.1-SNAPSHOT.jar

# Run with a specific profile
java -jar app.jar --spring.profiles.active=prod

# Override any property at runtime
java -jar app.jar --server.port=9090 --spring.datasource.url=jdbc:mysql://...

Deployment to a Linux Server

STEP 1: Build the JAR on your machine
  mvn clean package -DskipTests

STEP 2: Copy to the server
  scp target/app.jar ubuntu@your-server:/opt/myapp/

STEP 3: Create a systemd service so the app runs as a background process
  (on the server)

STEP 4: Start the app
  sudo systemctl start myapp
  sudo systemctl enable myapp   ← Auto-start on server reboot

Running with Docker

Docker packages your app and its runtime environment into a container image. The image runs identically on any machine with Docker installed.

# Dockerfile (place in project root)
FROM eclipse-temurin:17-jdk-alpine        ← Base image with Java 17
WORKDIR /app
COPY target/demo-0.0.1-SNAPSHOT.jar app.jar
EXPOSE 8080
ENTRYPOINT ["java", "-jar", "app.jar"]

# Build the image
docker build -t estudy247/my-app:1.0 .

# Run the container
docker run -d -p 8080:8080 \
  -e SPRING_PROFILES_ACTIVE=prod \
  -e DB_PASSWORD=secret \
  estudy247/my-app:1.0

Docker + Environment Variables

  Docker Container
  ┌──────────────────────────────────────────────┐
  │  Spring Boot App                             │
  │                                              │
  │  Reads: SPRING_PROFILES_ACTIVE=prod          │
  │  Reads: DB_PASSWORD=secret                   │
  │  Reads: SERVER_PORT=8080                     │
  │                                              │
  └──────────────────────────────────────────────┘
           ↑ injected at container start

Deployment to AWS

Option                 What It Is                         Best For
─────────────────────  ─────────────────────────────────  ─────────────────────
EC2                    Virtual server — full control      Custom setups
Elastic Beanstalk      Upload JAR → AWS manages infra     Quick deployment
ECS (Fargate)          Run Docker containers              Containerized apps
Lambda                 Serverless — pay per request       Lightweight functions

Deployment to Render / Railway (Simple Option)

1. Push your code to GitHub
2. Connect your GitHub repo to Render or Railway
3. Set environment variables in the platform dashboard
4. The platform builds and deploys automatically on every push

Health Check for Load Balancers

Production deployments typically sit behind a load balancer. Configure it to check your Actuator health endpoint:

Load Balancer Health Check: GET /actuator/health
Expected response: { "status": "UP" }

If "DOWN" → load balancer routes traffic away from this instance
If "UP"   → load balancer sends traffic to this instance

Deployment Checklist

Before Going Live                   Done?
─────────────────────────────────   ─────
Set spring.profiles.active=prod      □
Set ddl-auto=validate or none        □
Move all secrets to env variables    □
Enable only needed actuator endpoints□
Set logging.level.root=WARN          □
Configure HTTPS (SSL certificate)    □
Set up database connection pool      □
Configure proper error messages      □

Summary

• Spring Boot apps package into a single fat JAR that includes the embedded server
• Run with java -jar app.jar — no separate server installation needed
• Docker containerizes the app for consistent deployment across any environment
• Use environment variables to pass secrets and environment-specific config at runtime
• Always use the prod profile in production and disable ddl-auto table creation