Introduction
Load balancing across multiple application instances is a commonly used technique for optimizing resource utilization, maximizing throughput, reducing latency, and ensuring fault-tolerant configurations.
It is possible to use nginx as a very efficient HTTP load balancer to distribute traffic to several application servers and to improve performance, scalability and reliability of web applications with nginx.
Load balancing methods
The following load balancing mechanisms (or methods) are supported in nginx:
- round-robin — requests to the application servers are distributed in a round-robin fashion,
- least-connected — next request is assigned to the server with the least number of active connections,
- ip-hash — a hash-function is used to determine what server should be selected for the next request (based on the client’s IP address).
Default load balancing configuration
The simplest configuration for load balancing with nginx may look like the following:
http {
upstream myapp1 {
server srv1.example.com;
server srv2.example.com;
server srv3.example.com;
}
server {
listen 80;
location / {
proxy_pass http://myapp1;
}
}
}
In the example above, there are 3 instances of the same application running on srv1-srv3. When the load balancing method is not specifically configured, it defaults to round-robin. All requests are proxied to the server group myapp1, and nginx applies HTTP load balancing to distribute the requests. Continue reading “using nginx as http load balancer”