What is load balancer and how does it work in cloud environment?
By Pooja | 30th June 2025
Introduction
A load balancer is a system that automatically spreads incoming network traffic across multiple servers or resources. This helps maintain high availability, reliability, and scalability of applications. A load balancer is a system or service that distributes incoming network traffic (HTTP, HTTPS, TCP, etc.) across multiple backend resources. These backend resources can be physical servers, virtual machines (VMs), containers, or any compute instances capable of processing user requests
What Is a Load Balancer?
A load balancer serves as a traffic manager or middleman between clients, such as users accessing a website, and backend servers. Its main functions are to:
- Evenly distribute traffic among servers
- Prevent any single server from getting overwhelmed
- Detect and bypass unhealthy servers
- Improve overall performance and availability
How It Works in a Cloud Environment?
In cloud platforms like AWS, Azure, or Google Cloud, load balancers are generally fully managed services. Here’s how they work:
Client Request
- A user sends a request, like opening a website.
- The request first reaches the load balancer.
Traffic Distribution
- The load balancer checks factors like server load, health, and response time.
- It forwards the request to one of the available backend servers, such as EC2 instances or containers.
Health Checks
- The load balancer continuously monitors the health of backend servers.
- If a server fails, it is automatically taken out of the pool until it recovers.
Session Handling
It can maintain sticky sessions, ensuring the same user connects to the same server if needed.
Benefits in Cloud:
Elasticity: Scales up or down based on demand.
- High Availability: Distributes across multiple regions or availability zones.
- Fault Tolerance: Automatically reroutes traffic from failed servers.
- Security: Acts as a shield by terminating SSL and hiding backend servers.
Examples:
- AWS Elastic Load Balancer (ELB): Offers Application Load Balancer (ALB), Network Load Balancer (NLB), and Gateway Load Balancer.
- Azure Load Balancer: Provides both internal and public load balancing.
- Google Cloud Load Balancer: Global and scalable load balancing with integrated CDN.
How Load Balancing Works?
Load balancing in cloud computing is the process of distributing incoming network traffic across multiple servers, services, or computing resources in a cloud infrastructure. Its primary purpose is to ensure no single resource becomes a bottleneck, while maximizing availability, responsiveness, and fault tolerance. Cloud providers like AWS, Azure, and Google Cloud offer managed load balancing services that simplify setup, scaling, and management.
Why Load Balancing is Essential in Cloud Computing?
In traditional computing, physical servers could be manually configured for load balancing, but that method lacks flexibility and elasticity.
In cloud computing, where applications run on virtualized, scalable, and often ephemeral infrastructure, load balancing is critical for:
- Elastic Scaling: Automatically handle increases/decreases in demand.
- High Availability (HA): Keep the app accessible even if one server fails.
- Geographical Distribution: Route users to nearest servers for low latency.
- Micro services Architecture: Manage communication between multiple services.
Conclusion:
Load balancers are essential to modern, cloud-native architectures. They help manage distributed workloads, scale applications dynamically, and ensure your services remain fast and available, even under pressure. Whether you’re running a small startup or a large enterprise, using load balancing in the cloud allows you to build a resilient, efficient, and scalable system.