Network Load Balancers in AWS


In the world of online services, managing incoming traffic efficiently is crucial for a seamless user experience. Elastic Load Balancing (ELB) is a powerful tool that automatically distributes traffic across various targets, such as EC2 instances and containers. In this blog post, we'll explore the basics of ELB, specifically focusing on Network Load Balancers (NLB) and how to create them in AWS.

What is Elastic Load Balancing (ELB)?

Elastic Load Balancing is like a traffic cop for your website or app. It takes incoming visitors and directs them to different servers, making sure no single server gets overwhelmed. This ensures your application stays reliable and performs well, even as the number of users changes over time.

ELB supports different types of load balancers, including Application Load Balancers, Network Load Balancers, Gateway Load Balancers, and Classic Load Balancers. You can choose the one that fits your needs best. In this guide, we'll dive into Network Load Balancers.

Network Load Balancer Components

A Network Load Balancer consists of a few key parts:

  1. Load Balancer: Acts as the central point for client communication, distributing traffic among various targets like EC2 instances.
  2. Listeners: Check for connection requests from clients and forward them to target groups based on configured protocols and ports.
  3. Target Groups: Route requests to registered targets (e.g., EC2 instances) using specified protocols and port numbers. Supports TCP, UDP, TCP_UDP, and TLS protocols.

Network Load Balancer Overview

Network Load Balancers operate at the fourth layer of the OSI model and can handle millions of requests per second. They intelligently select a target from a group for incoming connection requests, striving to maintain a balance across servers.

When to Use Network Load Balancers

Consider using Network Load Balancers when you need to:

  • Handle high-throughput applications
  • Efficiently manage TCP and UDP traffic
  • Ensure fault tolerance across multiple Availability Zones

How to Create Network Load Balancer in AWS ALB

Creating a Network Load Balancer in AWS ALB involves several steps:

  1. Access AWS Management Console: Log in to your AWS account and navigate to the EC2 dashboard.
  2. Select the Load Balancer: Locate your desired ALB in the Load Balancers section.
  3. Configure Rules: Edit the listener for which you want to set up custom routing.
  4. Define Conditions and Actions: Add rules based on conditions like path patterns, headers, or query strings. Specify the target or action associated with each rule.
  5. Save Changes: Save your configurations, and the ALB will now use custom routing based on the defined rules.

Benefits of Network Load Balancers over Classic Load Balancers

Migrating to Network Load Balancers offers several advantages, including:

  • Ability to handle volatile workloads and scale to millions of requests per second.
  • Support for static IP addresses and Elastic IP addresses for the load balancer.
  • Flexibility to register targets by IP address, including those outside the VPC.
  • Capability to route requests to multiple applications on a single EC2 instance using multiple ports.
  • Support for containerized applications with Amazon Elastic Container Service (Amazon ECS).