With the right load balancing in place, the demand of increasing web traffic can become manageable, but how do you determine which load balancing algorithm is best suited for your applications? Does the ease of use of static load balancing better suit the services you provide, or would your system benefit from a more complex and dynamic set of algorithms to maximize efficiency? In this blog post, we discuss what to consider when deciding on the right load-balancing algorithm.
What is Load Balancing?
Load balancing is the process of distributing web application traffic across multiple servers in order to reduce strain on resources and allow services to run more efficiently. Considering the demand on today’s applications and the near-instant access to services users have with their smart devices, businesses need their web applications to be accessible all the time. Load balancing supports this high availability of these applications, reducing the risk of system failure by not overloading one single server. Instead, load balancing ensures web application demands are shared across multiple resources so that a single system does not fail due to immense processing requests.
Load balancing essentially provides the right roads to the destination. Much like a physical world, the proper infrastructure needs to be in place to support the movement of digital traffic. A load balancer will utilize this infrastructure efficiently. Without a load balancer, all the traffic would be directed down a single road. This would result in traffic jams, accidents, and the inability to reach the destination. The load balancer solves this issue by providing the right navigation, reducing the strain on the infrastructure, taking some traffic down alternative roads when another path is too busy, and ensuring everyone gets to where they need to go.
While eliminating the risk of system failure is the main goal of load balancing, there is more to it than that. It’s not just about system uptime and performance, it’s about ensuring a seamless user experience. Effective load balancing means users don’t notice slowdowns and hiccups. It means their interactions with web applications are fast and absent of any road bumps. A balanced and efficient service means your clients associate your brand with consistency and reliability–and building that trust in the services you provide is invaluable.
Static & Dynamic Algorithms
Load balancing algorithms can be broken down into two main categories: static and dynamic. As the titles suggest, static load balancing is more fixed and is unchanging regardless of the state of incoming traffic, while dynamic load balancing is adaptive and capable of changing how it sorts incoming requests based on the current demand servers face.
A static load balancing algorithm is the easiest to deploy. It does not actively account for system load or the size of information requests. Instead, it takes a more passive approach to managing incoming traffic based on a previously specified sorting rule, along with available system information, such as the number of servers available to support the web application. The algorithm takes this static information and manages incoming traffic based on that. It does not adapt to changing environments and adheres to its sorting rule.
An example of static load balancing is the round robin algorithm. With round robin, client requests are distributed among servers in sequence. When the last available server receives a request, the algorithm distributes from the top of the server list all over again. This algorithm distributes client requests to servers in the same order they are received. It is a simple algorithm to understand and get running, and for web applications that receive quick, predictable requests, it can work, but some applications require more complex load balancing to manage the traffic.
Dynamic load balancing actively accounts for the current load systems are processing. It takes a real-time approach to managing incoming traffic and is not bound to its patterned or random distributions. It can adapt and change alongside the traffic as the load increases and decreases. Dynamic load balancing is able to divert traffic away from servers that are already under strain and send those requests to servers that are managing fewer connections. This type of load balancing algorithm ensures systems are operating as efficiently as possible.
An example of dynamic load balancing is the least connection algorithm. This algorithm sends incoming traffic to servers that are managing fewer connections. In these instances, the load balancer will monitor the number of connections each server has active and direct traffic to those that have more capacity to handle incoming requests. The algorithm essentially attempts to equally manage the load across all resources, instead of delegating connections in the order that they come in. This type of load balancing prioritizes efficiency over the more superficial balancing of static algorithms like round robin.
There are no right or wrong decisions when it comes to determining which type of algorithm suits your needs best. Both static and dynamic algorithms will help manage incoming traffic for web applications, and it is certainly better to have a load balancer than to have none.
The resources you have at hand may be a determining factor between static and dynamic load balancing. Limited resources and predictable client requests may mean static algorithms are more suited for your systems, but even then, there are ways to make static algorithms more dynamic.
HAProxy provides the option for a more dynamic round robin, and with this algorithm, users can set the weight for the load-balancing servers. After the weight is configured, it can be adjusted dynamically with the Runtime API. The more heavily weighted servers will receive a larger portion of the traffic while still maintaining the rotating nature of round robin. Other alternatives such as setting your servers to a slow start and configuring agent checks can allow static load balancers to account for the current status of servers and adapt accordingly.
And while typically reaping the benefits of dynamic load balancing requires a more complex algorithm to deploy, with HAProxy, setting up a dynamic algorithm like least connection is fairly simple, removing the pain points of configuration and allowing you to dynamically load balance with ease. This more adaptive approach can outperform static algorithms. It’s just a matter of deciding which algorithm best suits your needs, and HAProxy empowers you to do so, with easy-to-deploy configurations for a variety of load balancing methods.
Decide on the algorithm that works best for you, and allow HAProxy to help you get started on managing connections and incoming traffic more efficiently than ever before.