Designs

Advance on-prem web application architecture

By SND
June 10, 2026 5 Min Read
0

On-Prem Enterprise Kubernetes Architecture Diagram:

┌─────────────────────────────────────────────────────────────┐
│                     EXTERNAL USERS                          │
├─────────────────────────────────────────────────────────────┤
│ Desktop Browser │ Mobile Browser │ Mobile App │ Partners    │
└─────────────────────────────────────────────────────────────┘
                              │
                              ▼
┌─────────────────────────────────────────────────────────────┐
│                           DNS                               │
├─────────────────────────────────────────────────────────────┤
│ Infoblox │ Active Directory DNS │ BIND DNS                 │
└─────────────────────────────────────────────────────────────┘
                              │
                              ▼
┌─────────────────────────────────────────────────────────────┐
│                    SECURITY LAYER                           │
├─────────────────────────────────────────────────────────────┤
│ F5 ASM / Cloudflare / Akamai / ModSecurity                 │
│ (WAF, DDoS Protection, Bot Protection, SSL)               │
└─────────────────────────────────────────────────────────────┘
                              │
                              ▼
┌─────────────────────────────────────────────────────────────┐
│                  LOAD BALANCER LAYER                        │
├─────────────────────────────────────────────────────────────┤
│ F5 LTM / HAProxy / NGINX Plus                              │
└─────────────────────────────────────────────────────────────┘
                              │
                              ▼
┌─────────────────────────────────────────────────────────────┐
│                  INGRESS CONTROLLER                         │
├─────────────────────────────────────────────────────────────┤
│ NGINX Ingress / HAProxy Ingress / Traefik                  │
└─────────────────────────────────────────────────────────────┘
                              │
                              ▼

═══════════════════════════════════════════════════════════════════════
                    ON-PREMISE KUBERNETES CLUSTER
═══════════════════════════════════════════════════════════════════════

┌─────────────────────────────────────────────────────────────┐
│                        UI LAYER                             │
├─────────────────────────────────────────────────────────────┤
│ Product-UI Service                                          │
│ ├─ product-ui-pod-1                                         │
│ ├─ product-ui-pod-2                                         │
│ └─ product-ui-pod-3                                         │
│                                                             │
│ Order-UI Service                                            │
│ ├─ order-ui-pod-1                                           │
│ └─ order-ui-pod-2                                           │
└─────────────────────────────────────────────────────────────┘
                              │
                              ▼

┌─────────────────────────────────────────────────────────────┐
│                    API GATEWAY LAYER                        │
├─────────────────────────────────────────────────────────────┤
│ Spring Cloud Gateway Service                               │
│ ├─ gateway-pod-1                                            │
│ ├─ gateway-pod-2                                            │
│ └─ gateway-pod-3                                            │
└─────────────────────────────────────────────────────────────┘
                              │
                              ▼

┌─────────────────────────────────────────────────────────────┐
│                   MICROSERVICES LAYER                       │
├─────────────────────────────────────────────────────────────┤
│ Product Service (ClusterIP)                                │
│ ├─ product-svc-pod-1                                        │
│ ├─ product-svc-pod-2                                        │
│ └─ product-svc-pod-3                                        │
│                                                             │
│ Order Service (ClusterIP)                                  │
│ ├─ order-svc-pod-1                                          │
│ ├─ order-svc-pod-2                                          │
│ └─ order-svc-pod-3                                          │
└─────────────────────────────────────────────────────────────┘
                              │
              ┌───────────────┴───────────────┐
              ▼                               ▼

┌─────────────────────────┐     ┌─────────────────────────┐
│      CACHE LAYER        │     │    MESSAGE BROKER       │
├─────────────────────────┤     ├─────────────────────────┤
│ Redis                   │     │ Kafka                   │
│ Hazelcast               │     │ RabbitMQ               │
└─────────────────────────┘     └─────────────────────────┘
              │                               │
              └───────────────┬───────────────┘
                              ▼

┌─────────────────────────────────────────────────────────────┐
│                    DATABASE LAYER                           │
├─────────────────────────────────────────────────────────────┤
│ PostgreSQL Primary                                          │
│ PostgreSQL Replica                                          │
│                                                             │
│ OR                                                          │
│                                                             │
│ Oracle RAC                                                  │
│ SQL Server AlwaysOn                                         │
└─────────────────────────────────────────────────────────────┘

═══════════════════════════════════════════════════════════════════════
                       OBSERVABILITY STACK
═══════════════════════════════════════════════════════════════════════

┌─────────────────────────────────────────────────────────────┐
│ LOGGING                                                     │
├─────────────────────────────────────────────────────────────┤
│ Fluent Bit → Elasticsearch/OpenSearch → Kibana            │
│ Splunk                                                     │
└─────────────────────────────────────────────────────────────┘

┌─────────────────────────────────────────────────────────────┐
│ MONITORING                                                  │
├─────────────────────────────────────────────────────────────┤
│ Prometheus → Grafana                                       │
│ Zabbix / Nagios                                            │
└─────────────────────────────────────────────────────────────┘

┌─────────────────────────────────────────────────────────────┐
│ DISTRIBUTED TRACING                                         │
├─────────────────────────────────────────────────────────────┤
│ Jaeger / Tempo / Zipkin                                    │
└─────────────────────────────────────────────────────────────┘

Traffic Flow

User
 ↓
DNS
 ↓
WAF (F5 ASM)
 ↓
Load Balancer (F5 LTM)
 ↓
NGINX Ingress
 ↓
Product UI / Order UI
 ↓
Spring Cloud Gateway
 ↓
Product Service / Order Service
 ↓
Redis / Kafka
 ↓
Database

External API Consumer Flow

Partner System
      ↓
F5 ASM
      ↓
F5 LTM
      ↓
NGINX Ingress
      ↓
Spring Cloud Gateway
      ↓
Product Service / Order Service

Internal Service Communication

Gateway
   ↓
product-svc (ClusterIP)
   ↓
product pods

Gateway
   ↓
order-svc (ClusterIP)
   ↓
order pods

This is a realistic enterprise on-prem architecture suitable for banks, insurance, retail, telecom, and large-scale Java/Spring microservices platforms.

Below is a detailed explanation of each layer, why it exists, what problems it solves, and what happens if you don’t have it.

1. Client Layer

Desktop Browser
Mobile Browser
Mobile App
Partner Systems

Purpose

This is where requests originate.

Examples:

  • Customer opens website
  • Mobile app calls APIs
  • External partner consumes APIs
  • Internal applications integrate with your platform

Why Needed?

Without clients, there is no traffic.

Different clients have different requirements:

ClientTypical Need
BrowserHTML/CSS/JS
Mobile AppJSON APIs
Partner SystemSecure API Integration

Example

User
 |
https://shop.company.com

2. DNS Layer

Infoblox
AD DNS
BIND

Purpose

Convert:

shop.company.com

into

10.10.20.100

Why Needed?

Humans remember:

api.company.com

not

10.20.30.40

Without DNS

Users would need to type IP addresses.

Impossible at enterprise scale.

3. Security / WAF Layer

F5 ASM
Cloudflare
Akamai
ModSecurity

Purpose

Protect applications before requests enter your environment.

Typical Attacks

SQL Injection

' OR 1=1 --

Cross Site Scripting

<script>alert('hack')</script>

API Abuse

1,000,000 requests/minute

DDoS

Millions of fake requests

Why Needed?

Without WAF:

Internet
   |
Application

Attackers directly hit application.

With WAF:

Internet
   |
WAF
   |
Application

Bad requests are blocked.

4. Load Balancer Layer

F5 LTM
HAProxy
NGINX Plus

Purpose

Distribute traffic across multiple application instances.

Example:

10000 Requests
       |
Load Balancer
   /     |      \
App1   App2   App3

Why Needed?

Without LB:

Users
  |
App1

If App1 crashes:

Application Down

With LB:

Users
  |
LB
 / \
A1 A2

Traffic automatically shifts.

5. Ingress Controller

NGINX Ingress
HAProxy Ingress
Traefik

Purpose

Acts as Kubernetes entry point.

Routes requests.

Example:

/api/*
   |
Gateway

/shop/*
   |
Product UI

/orders/*
   |
Order UI

Why Needed?

Without Ingress:

Every service needs external exposure.

product-ui
order-ui
gateway

Each needs:

LoadBalancer
NodePort

Hard to manage.

Ingress centralizes access.

6. UI Layer

Product UI
Order UI

Purpose

Present information to users.

Example:

React
Angular
Vue

Responsibilities

  • Render pages
  • Display products
  • Accept user input
  • Call APIs

Why Needed?

Users do not call databases.

Users interact with UI.

Example:

User
 |
Product UI
 |
Gateway

7. API Gateway Layer

Spring Cloud Gateway
Kong
Apigee

Purpose

Single entry point for APIs.

Responsibilities

Authentication

JWT Validation
OAuth2

Authorization

Can user access API?

Rate Limiting

100 req/min

Logging

Capture request details

Routing

/products -> product-service
/orders -> order-service

Why Needed?

Without Gateway:

Internet
 |
Product Service

Internet
 |
Order Service

Every service becomes internet-facing.

Security nightmare.

8. Microservices Layer

Product Service
Order Service
Payment Service
Inventory Service

Purpose

Implement business logic.

Example:

Product Service

Search Products
Create Products
Update Products

Order Service

Create Order
Cancel Order
Track Order

Why Needed?

Separation of concerns.

Instead of:

Huge Monolith

Use:

Product Team
Order Team
Payment Team

Independent deployment.

9. Service Discovery Layer

Kubernetes DNS
CoreDNS
ClusterIP

Purpose

Allow services to find each other.

Gateway calls:

http://product-svc

instead of:

10.1.1.45

Why Needed?

Pods constantly change IPs.

Example:

Pod Restart

New IP assigned.

Service Discovery hides this complexity.

10. Cache Layer

Redis
Hazelcast
Memcached

Purpose

Reduce database traffic.

Example

Product Search:

Without cache:

10000 Requests
10000 DB Queries

With cache:

10000 Requests
100 DB Queries

Benefits

  • Faster response
  • Reduced DB load
  • Better scalability

11. Message Broker Layer

Kafka
RabbitMQ
ActiveMQ

Purpose

Enable asynchronous processing.

Example

Order Placement:

Instead of:

Create Order
Send Email
Update Inventory
Process Payment

synchronously,

use:

Order Created Event
        |
      Kafka
       / | \
 Email Inventory Payment

Benefits

  • Loose coupling
  • Better scalability
  • Event-driven architecture

12. Database Layer

PostgreSQL
Oracle
SQL Server
MongoDB

Purpose

Store application data.

Examples:

Product Table

Product
Price
Category

Order Table

Order
Status
Amount

Why Needed?

Services are stateless.

Database stores persistent state.

13. Logging Layer

FluentBit
Elasticsearch
Kibana

or

OpenSearch

Purpose

Centralized logging.

Example

Logs from:

Ingress
Gateway
Services
Database

go into:

ELK

Why Needed?

Without centralized logs:

SSH to every server

Very difficult troubleshooting.

14. Monitoring Layer

Prometheus
Grafana

Purpose

Track health.

Metrics:

CPU
Memory
Latency
Error Rate
Requests/sec

Example

Dashboard:

Gateway CPU 90%

Alert before outage.

Why Needed?

Without monitoring:

Users report issue first

With monitoring:

Ops team knows before users

15. Distributed Tracing Layer

Jaeger
Tempo
Zipkin

Purpose

Track a request across services.

Example

User request:

Gateway
  |
Product Service
  |
Inventory Service
  |
Database

Tracing shows:

Gateway      20ms
Product      50ms
Inventory   900ms
Database     10ms

Root cause immediately visible.

16. Alerting Layer

Alertmanager
PagerDuty
OpsGenie

Purpose

Notify operations team.

Examples:

CPU > 90%
Database Down
Gateway Errors > 5%

Complete Request Flow

User
 |
DNS
 |
F5 ASM (Security)
 |
F5 LTM (Load Balancing)
 |
NGINX Ingress
 |
Product UI
 |
Spring Cloud Gateway
 |
Product Service
 |
Redis Cache
 |
PostgreSQL
 |
Kafka Events
 |
ELK / Prometheus / Jaeger

In One Sentence

  • DNS → Find application
  • WAF → Protect application
  • Load Balancer → Distribute traffic
  • Ingress → Kubernetes entry point
  • UI → User experience
  • API Gateway → Secure API entry
  • Microservices → Business logic
  • Service Discovery → Find services
  • Cache → Improve performance
  • Message Broker → Async processing
  • Database → Persist data
  • Logging → Troubleshooting
  • Monitoring → Health visibility
  • Tracing → Performance analysis
  • Alerting → Incident response

This layered architecture is what you’d typically see in large-scale on-prem enterprise systems built on Kubernetes and Spring Boot microservices.

How to convert same design in AWS ?

Web Application Architecture in AWS (Amazon)
Author

SND

Technology leader with 24 years of experience designing and delivering large-scale enterprise applications across multiple industries. Expertise in Java, Spring ecosystem, cloud-native architectures, and distributed systems. Strong background in Big Data, machine learning, and building scalable, high-performance platforms. Extensive experience with open-source technologies, databases, microservices, and modern application modernization initiatives. Proven track record of leading architecture, engineering, and digital transformation programs from concept to production.

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