Do we need Spring Cloud LoadBalancer when using Kubernetes on AWS?

Earlier (Before Kubernetes became popular)

In Spring Cloud microservices, the architecture looked like this:

Client
   |
API Gateway
   |
Spring Cloud LoadBalancer
   |
-------------------------
|        |        |
Order1  Order2  Order3

The application itself needed to know that there were multiple instances.

For example:

@LoadBalanced
@Bean
RestTemplate restTemplate() {
    return new RestTemplate();
}

or later with Spring Cloud LoadBalancer.

The load balancing happened inside the application (client-side load balancing).

---

Modern Enterprise (Kubernetes + AWS)

Now the architecture is usually:

Internet
      |
 AWS Application Load Balancer
      |
 Kubernetes Ingress
      |
 API Gateway Pods
      |
 Kubernetes Services
      |
 Product Pods

Everything is handled by the infrastructure.

• AWS ALB distributes requests to Kubernetes nodes/Ingress.
• Kubernetes Service distributes requests to pods.
• Kubernetes DNS resolves service names.

Your Spring Boot code simply exposes REST APIs.

No load-balancing code is needed for incoming requests.

---

Example

Suppose you have:

payment-service

Pod1
Pod2
Pod3

Your Order Service calls:

http://payment-service/pay

You don’t specify:

Pod1

or

Pod2

or

10.10.2.45

Kubernetes automatically sends the request to one of the healthy pods.

---

So is Spring Cloud LoadBalancer obsolete?

Not completely.

It is still useful in some scenarios:

1. Without Kubernetes

If you’re running microservices on:

• Virtual Machines
• EC2 instances
• Docker Compose
• Bare-metal servers

then Spring Cloud LoadBalancer is still useful.

---

2. Kubernetes

Usually no.

Kubernetes already provides:

• Service Discovery
• DNS
• Load Balancing
• Failover

Using Spring Cloud LoadBalancer would often duplicate functionality.

---

Do enterprise developers configure AWS ALB?

Usually DevOps or Platform Engineers do.

Developers typically:

• Write Spring Boot APIs.
• Create a Deployment manifest.
• Create a Service manifest.
• Optionally define an Ingress resource.

The infrastructure team or cloud platform provisions and manages the AWS ALB.

---

Typical responsibilities

Component	Developer	DevOps/Platform
Spring Boot APIs	✅
Docker image	✅
Kubernetes Deployment	✅ (often)	✅
Kubernetes Service	✅ (often)	✅
AWS ALB		✅
Auto Scaling		✅
SSL Certificates		✅
DNS		✅

---

In your interviews

If someone asks:

Do we need Spring Cloud LoadBalancer when using Kubernetes on AWS?

A strong answer is:

“Generally, no. Kubernetes Services already provide internal load balancing across pods, and AWS Application Load Balancer handles external traffic. Spring Cloud LoadBalancer is more useful in environments without Kubernetes or when client-side load balancing is specifically required.”