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When you're building Java applications with Quarkus, managing environment-specific configurations is crucial—especially when connecting to services like PostgreSQL. Thanks to Quarkus’s support for profiles and YAML-based configuration, it’s easy to set up clean, isolated environments for development and production.
In this guide, we’ll walk through configuring PostgreSQL in a Quarkus application using Docker for local development and Kubernetes for production. We’ll organize our configuration using application-dev.yml and application-prod.yml so that switching between environments is smooth and low-maintenance.

1. Add the Necessary Dependencies

First, make sure your pom.xml includes the right dependencies: 
<dependencies>
  <!-- Quarkus JDBC support for PostgreSQL -->
  <dependency>
    <groupId>io.quarkus</groupId>
    <artifactId>quarkus-jdbc-postgresql</artifactId>
  </dependency>

  <!-- Hibernate ORM for JPA support -->
  <dependency>
    <groupId>io.quarkus</groupId>
    <artifactId>quarkus-hibernate-orm</artifactId>
  </dependency>

  <!-- YAML configuration support -->
  <dependency>
    <groupId>io.quarkus</groupId>
    <artifactId>quarkus-config-yaml</artifactId>
  </dependency>

  <!-- Kubernetes configuration (for prod) -->
  <dependency>
    <groupId>io.quarkus</groupId>
    <artifactId>quarkus-kubernetes-config</artifactId>
  </dependency>
</dependencies>
These enable PostgreSQL support, JPA integration, YAML-based configuration, and Kubernetes ConfigMap/Secret loading.

2. Start PostgreSQL Using Docker (Development)

Here’s a simple command to start a PostgreSQL container for development: 
docker run --name postgres-dev \
  -e POSTGRES_USER=devuser \
  -e POSTGRES_PASSWORD=devpass \
  -e POSTGRES_DB=devdb \
  -p 5432:5432 \
  -d postgres:14
This creates a local PostgreSQL instance with the database devdb, running on port 5432.

3. Configure application-dev.yml

Now let’s define development-specific settings in src/main/resources/application-dev.yml: 
"%dev":
  quarkus:
    datasource:
      db-kind: postgresql
      jdbc:
        url: jdbc:postgresql://localhost:5432/devdb
        driver: org.postgresql.Driver
      username: devuser
      password: devpass
    hibernate-orm:
      database:
        generation: drop-and-create
      dialect: org.hibernate.dialect.PostgreSQLDialect
This setup ensures your dev environment uses Docker-hosted PostgreSQL and automatically regenerates the schema on app startup.
Run the app with: 
./mvnw quarkus:dev -Dquarkus.profile=dev

4. Production Setup Using Kubernetes

For production, you should avoid hardcoded values. Kubernetes allows you to manage configurations using ConfigMaps and Secrets.

4.1: Create a ConfigMap

apiVersion: v1
kind: ConfigMap
metadata:
  name: postgres-config
data:
  db-kind: postgresql
  jdbc-url: jdbc:postgresql://postgres-service:5432/proddb
  hibernate-dialect: org.hibernate.dialect.PostgreSQLDialect

4.2: Create a Secret

apiVersion: v1
kind: Secret
metadata:
  name: postgres-secret
type: Opaque
data:
  username: cHJvZHVzZXI=  # base64 for 'produser'
  password: cHJvZHBhc3M=  # base64 for 'prodpass'

5. Configure application-prod.yml

In your src/main/resources/application-prod.yml, refer to values through environment variables (these will be injected by Kubernetes): 
"%prod":
  quarkus:
    datasource:
      db-kind: ${DB_KIND:postgresql}
      jdbc:
        url: ${JDBC_URL}
        driver: org.postgresql.Driver
      username: ${DB_USERNAME}
      password: ${DB_PASSWORD}
    hibernate-orm:
      database:
        generation: validate
      dialect: ${HIBERNATE_DIALECT}
    kubernetes-config:
      enabled: true
      config-maps: postgres-config
      secrets: postgres-secret
This file instructs Quarkus to dynamically load its config from the Kubernetes environment.

6. Configure Kubernetes Deployment

In your Quarkus deployment file, make sure to set up environment variables from the ConfigMap and Secret: 
env:
  - name: QUARKUS_PROFILE
    value: prod
  - name: DB_KIND
    valueFrom:
      configMapKeyRef:
        name: postgres-config
        key: db-kind
  - name: JDBC_URL
    valueFrom:
      configMapKeyRef:
        name: postgres-config
        key: jdbc-url
  - name: HIBERNATE_DIALECT
    valueFrom:
      configMapKeyRef:
        name: postgres-config
        key: hibernate-dialect
  - name: DB_USERNAME
    valueFrom:
      secretKeyRef:
        name: postgres-secret
        key: username
  - name: DB_PASSWORD
    valueFrom:
      secretKeyRef:
        name: postgres-secret
        key: password
This setup allows your Quarkus app to securely connect to PostgreSQL in Kubernetes without hardcoding credentials.
By using application.yml profiles and separating your dev and prod configurations, you get the best of both worlds: fast and flexible development with Docker, and secure, scalable production deployment via Kubernetes.
Quarkus makes it easy to manage environment-specific behavior with its %profile syntax. Combine this with Kubernetes' configuration management tools, and your PostgreSQL integration stays clean, portable, and maintainable. whether you’re running locally or in the cloud.

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