How to Configure IBM Db2 in Dropwizard

July 30, 2025

When you're building a Dropwizard application that needs a robust relational database, IBM Db2 is a solid choice. Whether you're working locally or deploying in production, this guide walks you through setting up Db2 with Docker for development and Kubernetes for secure, scalable production environments. We’ll also show how to keep your setup clean using config-dev.yml for development and config-prod.yml for production.

1. Add Dependencies in `pom.xml`

First, update your Maven build to include necessary libraries:

<dependencies>
  <!-- Dropwizard core -->
  <dependency>
    <groupId>io.dropwizard</groupId>
    <artifactId>dropwizard-core</artifactId>
    <version>${dropwizard.version}</version>
  </dependency>

  <!-- IBM Db2 JDBC driver -->
  <dependency>
    <groupId>com.ibm.db2</groupId>
    <artifactId>jcc</artifactId>
    <version>${db2.jcc.version}</version>
  </dependency>

  <!-- Kubernetes client (optional but useful) -->
  <dependency>
    <groupId>io.fabric8</groupId>
    <artifactId>kubernetes-client</artifactId>
    <version>${fabric8.version}</version>
  </dependency>
</dependencies>

You now have Dropwizard, the IBM Db2 JDBC driver, and optional Kubernetes support for production-grade deployment.

2. Run Db2 Locally with Docker

For development, let’s spin up Db2 using Docker:

version: '3'
services:
  db2:
    image: icr.io/db2:latest
    environment:
      DB2INST1_PASSWORD: db2inst1pwd
      LICENSE: accept
    ports:
      - "50000:50000"
    command: db2start

Run the container:

docker-compose up -d

Db2 will be available via localhost:50000, with credentials you specified (db2inst1/db2inst1pwd).

3. Create `config-dev.yml` for Development

Your local configuration might look like:

server:
  applicationConnectors:
    - type: http
      port: 8080

database:
  driverClass: com.ibm.db2.jcc.DB2Driver
  user: db2inst1
  password: db2inst1pwd
  url: jdbc:db2://localhost:50000/sample
  validationQuery: SELECT 1 FROM sysibm.sysdummy1

Map properties using a config POJO:

public class DbConfig {
  @JsonProperty public String driverClass;
  @JsonProperty public String user;
  @JsonProperty public String password;
  @JsonProperty public String url;
  @JsonProperty public String validationQuery;
}
public class AppConfig extends Configuration {
  @JsonProperty("database")
  public DbConfig database = new DbConfig();
}

In your Application class, initialize Db2:

ManagedDataSource ds = config.database.build(environment.metrics(), "db");
environment.lifecycle().manage(ds);

Run locally with:

java -jar target/myapp.jar server config-dev.yml

Your Dropwizard app will now connect to the local Db2 instance for development.

4. Configure Kubernetes for Production

When deploying, avoid hardcoding credentials. Use Kubernetes ConfigMaps and Secrets:

kubectl create configmap db2-config \
  --from-literal=DB_URL=jdbc:db2://db2-service:50000/proddb \
  --from-literal=DB_DRIVER=com.ibm.db2.jcc.DB2Driver \
  --from-literal=DB_VALIDATION_QUERY=SELECT+1+FROM+sysibm.sysdummy1

kubectl create secret generic db2-secret \
  --from-literal=DB_USER=db2prod \
  --from-literal=DB_PASSWORD=prodPassw0rd

These store your production database URL and credentials securely.

5. Create `config-prod.yml` for Production Use

Use environment variables in your production config:

server:
  applicationConnectors:
    - type: http
      port: 8080

database:
  driverClass: ${DB_DRIVER}
  user: ${DB_USER}
  password: ${DB_PASSWORD}
  url: ${DB_URL}
  validationQuery: ${DB_VALIDATION_QUERY}

Dropwizard will substitute these at run time using Kubernetes-provided values.

6. Kubernetes Deployment Snippet

Include the environment variables in your deployment manifest:

env:
  - name: DB_DRIVER
    valueFrom:
      configMapKeyRef:
        name: db2-config
        key: DB_DRIVER
  - name: DB_URL
    valueFrom:
      configMapKeyRef:
        name: db2-config
        key: DB_URL
  - name: DB_VALIDATION_QUERY
    valueFrom:
      configMapKeyRef:
        name: db2-config
        key: DB_VALIDATION_QUERY
  - name: DB_USER
    valueFrom:
      secretKeyRef:
        name: db2-secret
        key: DB_USER
  - name: DB_PASSWORD
    valueFrom:
      secretKeyRef:
        name: db2-secret
        key: DB_PASSWORD

Deploy and start your app with:

java -jar myapp.jar server config-prod.yml

Now your Dropwizard application connects securely to Db2 in production.

7. Why This Setup Makes Sense

Quick local setup: Docker spins up Db2 fast for clean testing.
Secure production: Credentials are hidden in Kubernetes resources—not in code.
Clean configs: Separate dev and prod YAML keep things tidy and manageable.
Future-ready: Easily extend this to pool connections or scale your database tier.

Mixing Dropwizard with IBM Db2 using this pattern gives you a robust foundation for both development and production. By localizing environment setups and applying Kubernetes best practices, you're primed for real-world use—whether you're building an enterprise API, transitioning to the cloud, or just experimenting with Db2.

1. Add Dependencies in pom.xml