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8.4 Production Profiles & Configuration

← Back to Chapter 8: Testing, Deployment & Production-Ready Spring Boot

Deploying enterprise services into cloud environments (Kubernetes, AWS ECS, GCP Cloud Run) mandates adherence to the Twelve-Factor App methodology, specifically externalizing all secrets and environment configurations.

1. The Twelve-Factor Config Principle​

"Store config in the environment."

A codebase should be deployed to multiple environments without modifying a single line of code or recompiling the jar archive.

Rule of Environment Variables in Spring Boot:​

Spring Boot relaxes property names so that environment variables automatically map to YAML properties:

  • Property spring.datasource.password ➔ Environment variable SPRING_DATASOURCE_PASSWORD
  • Property app.mail.sender-address ➔ Environment variable APP_MAIL_SENDER_ADDRESS

2. Secrets Management & Vault Integration​

Never commit API keys, database credentials, or private JWT signing secrets to Git repositories:

# application-prod.yml
spring:
  datasource:
    url: ${DB_JDBC_URL}
    username: ${DB_USERNAME}
    password: ${DB_PASSWORD}
    hikari:
      maximum-pool-size: 20
      minimum-idle: 5
      connection-timeout: 30000
      idle-timeout: 600000
      max-lifetime: 1800000

app:
  jwt:
    secret-key: ${JWT_SIGNING_SECRET}

In Kubernetes environments, these environment variables are populated dynamically from Kubernetes Secrets or external secret managers (HashiCorp Vault, AWS Secrets Manager).

3. Graceful Shutdown Configuration​

When a container is terminated during Kubernetes rolling deployments, pods receive a SIGTERM signal. Without graceful shutdown, active in-flight HTTP requests are severed abruptly:

server:
  shutdown: graceful # Waits for active requests to finish

spring:
  lifecycle:
    timeout-per-shutdown-phase: 30s # Max grace period before force SIGKILL

When configured:

  1. Embedded Tomcat stops accepting new inbound connections immediately.
  2. In-flight HTTP transactions are allowed up to 30 seconds to complete gracefully.
  3. Database pools and thread pools are cleanly terminated.