HAProxy: Tutorial & Best Practices

A high-availability load balancer that is used to distribute incoming requests across multiple servers.

HAProxy (High Availability Proxy) is a free, open-source software that provides a high availability load balancer and proxy server for TCP and HTTP-based applications. It is designed to route traffic from clients to servers based on various factors, such as the health of the servers, the load on each server, and the configured routing rules. It can also be used to improve the performance and reliability of applications by distributing incoming requests across multiple servers.

To use HAProxy for load balancing and failover, you will need to install it on a server and configure it to route traffic to your application servers. Here is a high-level overview of the process:

  • Install HAProxy on a server that is separate from your application servers. This server will act as the load balancer.

  • Configure the load balancer to listen on a specific port for incoming traffic. For example, if you want to load balance HTTPS traffic, you might configure the load balancer to listen on port 443.

  • Add your application servers to the load balancer's configuration. This will tell the load balancer where to send incoming traffic.

  • Configure the load balancing algorithm. There are several different algorithms you can use to distribute traffic between your application servers, such as round-robin, least connections, and source hashing.

  • Configure health checks to ensure that only healthy servers receive traffic. You can specify the interval at which the load balancer checks the health of each server, as well as the type of check to perform (e.g., an HTTP request or a TCP connection).

  • Optionally, configure any additional features you need, such as SSL termination, authentication, or HTTP compression. You can also use HAProxy to distribute connections to a database such as MariaDB.

  • Start the load balancer and monitor it to ensure it is functioning correctly.

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