Load Balancer in AWS

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krishnapal rawat
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3 min read

What Are Load Balancers?

Load balancers act as intermediaries between clients and backend resources, distributing incoming network traffic across multiple targets, such as Amazon EC2 instances, containers, or Lambda functions. They are essential for maintaining application reliability, improving fault tolerance, and enabling seamless scaling.

1. Application Load Balancer (ALB):

ALBs are Layer 7 load balancers that operate at the application layer, making routing decisions based on the content of the request. They are ideal for routing HTTP and HTTPS traffic and are well-suited for applications like web servers, microservices, and APIs. Some key features include:

  • Content-Based Routing: ALBs support content-based routing, allowing you to route requests based on URL paths, hostnames, or request headers. This is useful for implementing advanced routing and can simplify your application architecture.

  • Path-Based Routing: You can route traffic to different services or microservices within your application by defining specific paths in the URL.

  • HTTPS Support: ALBs can terminate SSL/TLS connections, providing security for your applications. They also support features like Server Name Indication (SNI) and client certificate validation.

2. Network Load Balancer (NLB):

NLBs are Layer 4 load balancers that operate at the transport layer, making routing decisions based on IP protocol data. They are ideal for handling TCP/UDP traffic and are well-suited for scenarios where extreme performance, low latency, and high throughput are critical. Key features include:

  • High Throughput: NLBs provide high throughput and low-latency handling of network traffic. They are designed for high-performance applications and can efficiently route traffic to backend targets.

  • TLS Passthrough: NLBs can pass through TLS-encrypted traffic to the backend targets, making them suitable for handling encrypted communication.

  • Source IP Affinity: NLBs support source IP affinity, which enables session persistence, ensuring that all requests from the same client are directed to the same backend target.

3. Gateway Load Balancer (GWLB):

GWLB is a recently introduced AWS load balancer that operates at both the network and transport layers, making it suitable for a wide range of use cases. It's designed for scenarios where you need to manage multiple IP addresses or route traffic to different virtual appliances. Key features include:

  • High Availability: GWLB provides high availability by distributing traffic across multiple Availability Zones (AZs). It's ideal for scenarios where fault tolerance and redundancy are critical.

  • Ingress and Egress Routing: GWLB can be used for both ingress and egress traffic routing, making it versatile for various network architectures.

  • IP Address Management: GWLB enables efficient IP address management and can be used with Network Address Translation (NAT) gateways, VPNs, and more.

Choosing the Right Load Balancer

Selecting the right load balancer depends on your application's requirements:

  • ALB is suitable for applications that require routing based on content, such as web servers, microservices, and APIs.

  • NLB is ideal for applications requiring high throughput and low latency, like gaming, IoT, and VoIP.

  • GWLB is a versatile choice for managing network traffic with high availability, making it a good fit for virtual appliances and complex network architectures.

By understanding the capabilities and use cases of these load balancers, you can make informed decisions to ensure your applications are highly available, scalable, and performant in the AWS cloud.

happy learning :) .............

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