4 Best Open Source Load Balancers in 2024

What is load balancing?

Load balancing is the process of distributing incoming traffic across a group of servers or resources to maximize the use of resources, improve performance, and increase the availability of services.

Image from AWS Cloud Computing Concepts Hub

It is typically performed by a load balancer, a dedicated device or software that sits between the client and the servers and routes traffic to the appropriate server based on a set of rules or algorithms. The load balancer can be configured to use a variety of algorithms to determine how to distribute the traffic, such as round-robin, least connections, or source IP hash.

When a client sends a request to a service that is balanced, the load balancer receives the request and selects a server to handle the request based on the configured algorithm. The balancer then forwards the request to the selected server and returns the server's response to the client. The load balancer will route requests to the remaining servers if the server goes down and automatically send requests if a new server is added.

What are the 5 types of load balancers?

Several types of load balancers are commonly used in modern networks and cloud environments, including:

1. Network load balancers: These load balancers operate at the OSI model's network layer (layer 4) and are responsible for distributing incoming traffic across a group of servers based on IP address and port number. Network load balancers are often used to distribute traffic to application servers or to balance the load across multiple servers in a web farm.
2. Application load balancers: These load balancers operate at the application layer (layer 7) of the OSI model and are responsible for distributing incoming traffic based on HTTP request characteristics, such as the URL or the host header. Application load balancers are often used to route traffic to specific applications or services based on the content of the request.
3. Gateway load balancers: These load balancers operate at the network edge and are responsible for routing traffic to backend servers based on the request's destination. Gateway load balancers are often used to route traffic to multiple applications or services, or to provide secure access to servers from the internet.
4. Global load balancers: These load balancers are used to distribute traffic across multiple regions or data centers and are often used in large-scale, highly available systems where it is important to ensure that traffic is distributed evenly across multiple locations.
5. Server load balancers: These are used to distribute traffic within a single server or host, and are often used to balance the load across multiple CPU cores or to distribute traffic to different processes or containers running on the same host.

Top 4 open-source load balancers:

1. Traefik

Traefik is a popular open-source edge router and load balancer that makes it easy to expose applications and services running in a network to the internet. It can automatically detect and reconfigure itself when new services are added or removed, making it easy to deploy and scale applications without worrying about manual configuration.

The platform supports multiple load balancing algorithms, including round-robin and least connections, and can be configured to work with various backends, such as Docker, Kubernetes, and more. It has a clean, intuitive configuration format and a friendly web interface for managing and monitoring your services.

Traefik also offers advanced features like active-active clustering for high availability, and support for health checks to ensure that only healthy servers are used for handling traffic. It has a simple configuration format and a well-documented configuration language, making it easy to set up and customize for your specific needs.

The software is written in the Go programming language and is available for Linux, macOS, and Windows operating systems. It can be run as a standalone application or a service in a container orchestration platform like Docker or Kubernetes.

2. Nginx

NGINX is a popular open-source web server and reverse proxy that can also be used as a load balancer. It is known for its high performance and low resource usage, making it a good choice for environments with high traffic or limited resources.

It supports a wide range of load-balancing algorithms, including round-robin, least connections, and source IP hash, and can be configured to work with various backends, such as HTTP, FastCGI, and TCP. It offers session persistence and health checks to ensure reliable service delivery. NGINX also supports active-active clustering for high availability.

NGINX has a simple configuration format and a well-documented configuration language, making it easy to set up and customize for your specific needs. It can be configured using a configuration file or through command-line arguments, and offers several tools and utilities for managing and monitoring your load balancer. NGINX is written in the C programming language and is available for Linux, macOS, and Windows operating systems. It can be run as a standalone application or a service in a container orchestration platform like Docker or Kubernetes.

3. Seesaw

Seesaw is an open-source load-balancing platform that is simple to use and easy to start with. It is written in the Go programming language and intended to be used in environments where several servers or services must be load balanced.

It offers a range of features to make it easy to configure and manage your load balancer, including a web-based user interface, a command-line interface, and integration with popular configuration management tools like Ansible and puppet. It supports multiple load balancing algorithms, including round-robin, least connections, and source IP hash, and can be configured to work with various backends, such as TCP, HTTP, and HTTPS.

Some advanced features like active-active clustering for high availability, and support for health checks are also provided to ensure that only healthy servers are used for handling traffic. It has a simple configuration format and a well-documented configuration language, making it easy to set up and customize for your specific needs.

4. HAProxy

HAProxy is a popular open-source load balancer and reverse proxy widely used to distribute incoming traffic across multiple servers or applications. It is known for its high performance and low resource usage, making it a good choice for environments with high traffic or limited resources.

It supports a wide range of load-balancing algorithms, including round-robin, least connections, and source IP hash, and can be configured to work with various backends, such as HTTP, FastCGI, and TCP. It offers session persistence and health checks to ensure reliable service delivery. HAProxy also supports active-active clustering for high availability.

The product has a simple configuration format and a well-documented configuration language, making it easy to set up and customize for your specific needs. It can be configured using a command-line interface or a configuration file, and offers many tools and utilities for managing and monitoring your load balancer. HAProxy is written in the C programming language and is available for Linux, FreeBSD, and Solaris operating systems.

How to choose the right type of load balancer?

There are several factors to consider when choosing the right type of load balancer for your needs. Here are a few key considerations:

1. Load balancing algorithm: Different load balancers support different algorithms for distributing traffic among servers or applications. Consider which algorithm is most appropriate for your use cases, such as round-robin, least connections, or source IP hash.
2. Compatibility with backends: Make sure that the load balancer you choose is compatible with the servers or applications you want to load balance. This may include support for specific protocols (e.g. HTTP, HTTPS, TCP) or integration with specific technologies (e.g. Docker, Kubernetes).
3. Performance and scalability: Choose a load balancer that is capable of handling the traffic levels and number of connections you expect to see. Consider the load balancer's resource usage and any scalability limitations.
4. Ease of use: Look for a load balancer that is easy to set up and configure, with clear documentation and a simple configuration format. Consider whether you need a user-friendly web interface or advanced features like custom routing rules or middleware.
5. High availability: If your application or service requires high availability, choose a load balancer that offers active-active clustering or other mechanisms for ensuring continuous service availability.
6. Budget: Consider the cost of the load balancer, including any licensing or subscription fees, and compare this to your budget and the value it will provide to your organization.

Conclusion

This article introduced load balancers, a set of tools used to distribute traffic across servers. We discussed different types of load balancers and how you might choose the right type. And we also listed the top 4 open-source load balancers for you.

As your load balancers are running, they can run into issues. You can use a cloud-based monitoring service, such as Better Stack Uptime, to monitor the status of the load balancers and get notified when something happens.

If you made it to this part of the article, thank you very much for reading, and make sure to check out our Scaling Node.js tutorial, where we discuss load balancing in Node.js applications.

Article by

Better Stack Team

Got an article suggestion? Let us know

This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.