Can Applications Be Load Balanced on AWS?

Amazon Web Services or AWS offers a vast array of innovative, cutting-edge solutions, with many opting to build and host their applications with Amazon’s technology. 

As a server-reliant technology, apps of all kinds — from web apps to mobile apps — can benefit from the use of a load balancer. Load balancing involves the strategic distribution of incoming client requests in a manner that results in greater speed, better reliability, less downtime, enhanced performance, and improved user experience. 

This begs the question: can applications be load balanced on AWS? And how does load balancing work, anyways? 

How Does Load Balancing Work?

Load balancing works by sending server requests — also known as client requests — to a central hub server, known as the load balancer. This central server performs an analysis of the server requests by evaluating traits that differ depending on the type of load balancer and the type of server traffic that it is handling. 

The load balancer’s primary function is to accept groups or “clumps” of incoming client requests which would otherwise flow to a single server, causing a potential overload that may result in a server slowdown or crash – an event that could cause the ever-dreaded downtime. The load balancer breaks up those clumps, evaluating each request using a load balancing algorithm, which determines how each server request is distributed. 

In addition, many load balancers perform health checks on the servers, thereby minimizing error messages and instances of poor performance. Each server is queried and those  that do not pass the health check are removed from the pool and flagged for maintenance.

This still leaves the question, though: Can applications be load balanced on AWS? 

Can You Load Balance Applications on AWS?

The short answer is yes, applications can be load balanced on AWS, although you must meet certain requirements such as hosting the app on the AWS platform instead of on another third-party host. AWS load balancing can also be used in conjunction with applications that are hosted on-premises, provided you use the app’s backend IP addresses as targets in your load balancer configuration. 

AWS was actually a front-runner in the world of load balancing technology. In a world dominated by clunky hardware load balancers since they were invented in the mid-1990s, Amazon developed one of the very first modern software load balancers: the Classic Load Balancer or CLB. 

There are a total of three AWS Elastic Load Balancing (ELB) options available. The term “elastic” refers to auto-scaling capabilities, which allow the load balancer to add or subtract resources on an as-needed basis in order to meet demand fluctuation for a specific workload. AWS offers the Application Load Balancer (ALB), the Network Load Balancer (NLB), and the aforementioned Classic Load Balancer.

The Network Load Balancer works at OSI Layer 4. which is the transport layer, with the capability to handle millions of incoming client requests per second with TCP/IP protocol and UDP traffic. As the name suggests, this particular form of AWS Elastic Load Balancer is ideally designed for use with networks. This means that the NLB is not the ideal load balancing option for use with applications. 

The Application Load Balancer is a much better option for app load balancing on AWS. Introduced in 2016, the ALB works at OSI Layer 7, the transport layer. This load balancer distributes incoming server traffic by evaluating the content of the client request, such as the URL or other header content.

Overall, the Application Load Balancer’s functions are similar to the Classic Load Balancer, except there are a number of enhancements and additional capabilities available in the ALB. 

When comparing the Network Load Balancer with the Application Load Balancer, there is a major difference when it comes to how the two handle incoming server requests. The NLB forwards client requests to the server pool without performing any sort of analysis on the request, whereas the ALB takes an in-depth look at application layer protocol data that is embedded within the header. This analysis does take time, resulting in a slightly longer load balancing timeframe. But the Application Load Balancer is ultimately more effective in distributing server traffic because it has more data to draw from when deciding how it will distribute client requests. 

The Classic Load Balancer was designed to work with EC2-Classic network applications, providing load balancing at the connection level and the request level across multiple Amazon EC2 instances. Unfortunately, though, as of August 15, 2022, the AWS Classic Load Balancer’s EC2-Classic Network was retired and officially deprecated. This means that users of the AWS Classic Load Balancer were required to migrate to the Virtual Private Cloud (VPC). The AWS Virtual Private Cloud is the only place where the AWS Classic Load Balancer is now available. 

While there are numerous configurations, the Application Load Balancer (ALB) is typically regarded as the best AWS Elastic Load Balancing technology for those who are seeking to maximize performance, availability, speed, and reliability for their applications. 

Can Applications Be Load Balanced Outside of AWS?

While many prefer to keep all of their services within one service provider such as Amazon Web Services, others may choose to seek out another load balancing service provider due to a need for different capabilities or features. 

There are numerous load balancing options outside of AWS that may be considered. It’s possible to use third-party load balancers with applications that are hosted on Amazon Web Services, providing additional options to improve user experience and maximize performance. One of those options is Resonate, which offers cutting-edge technology to those in need of application load balancing. 

At Resonate, we specialize in scalable, cost-effective, and reliable high-performance load balancing technology for applications of all kinds. We invite you to reach out to the team here at Resonate to discuss your load balancing needs and our experts will consult on the best LB solution for your precise requirements. We look forward to finding the ideal technology for your application load balancing needs.