From WARs to Containers: How Build Automation Evolved from Traditional Web Apps to Microservices

In the
world of software delivery, how we build and ship applications has changed dramatically.
Let’s take a simple look at the difference between traditional web build automation (think WAR files and Tomcat) and microservices build automation (think Docker and Kubernetes).

🔹 Traditional Web Build Automation (The Monolith Way)

In a monolithic world, you usually had one giant codebase producing a WAR/EAR file.
The build automation process looked something like this:

1.Checkout Code
Single repo with the entire application.

git clone https://github.com/company/monolith-app.git

2.Compile & Package
Use Maven to build everything at once:

mvn clean package

Output → target/myapp.war

3.Deploy
Copy WAR into Tomcat or JBoss:

cp target/myapp.war $TOMCAT_HOME/webapps/

4.Restart Server
Usually required downtime.

⚠️ Problems:

Slow builds (even for tiny changes).

Deployments were risky.

Scaling meant buying a bigger server.

🔹 Microservices Build Automation (The Cloud-Native Way)

With microservices, each service has its own repo and build pipeline.
The process looks very different:

1.Checkout Only That Service

git clone https://github.com/company/user-service.git

2.Compile & Package
Each service builds independently:

mvn clean package

Output → target/user-service.jar

3.Dockerize It
Wrap the service into a container:

FROM eclipse-temurin:17-jdk
COPY target/user-service.jar app.jar
ENTRYPOINT ["java", "-jar", "app.jar"]

Build the image:

docker build -t myorg/user-service:1.0 .

4.Push to Registry

docker push myorg/user-service:1.0

5.Deploy to Kubernetes

apiVersion: apps/v1
kind: Deployment
metadata:
name: user-service
spec:
replicas: 3
selector:
matchLabels:
app: user-service
template:
metadata:
labels:
app: user-service
spec:
containers:
- name: user-service
image: myorg/user-service:1.0
ports:
- containerPort: 8080