Detailed introduction to the high scalability and traffic diversion policy control method of Nginx reverse proxy server

High scalability and traffic diversion policy control method of Nginx reverse proxy server

Introduction:
In the context of today's growing Internet applications, service high availability and load balancing have become important subject. In order to meet these needs, Nginx reverse proxy server came into being. As a high-performance HTTP and reverse proxy server, Nginx is highly regarded for its excellent scalability and flexible traffic diversion policy control method.

1. High scalability of Nginx reverse proxy server
High scalability is a major feature of Nginx, which can easily cope with application scenarios of high traffic and large-scale access. The high scalability of Nginx is mainly reflected in the following aspects:

1. Asynchronous event-driven:
   Nginx adopts an asynchronous event-driven processing model, that is, each connection is on an independent event Operates through non-blocking I/O and can handle thousands of concurrent connections. This asynchronous event-driven model allows Nginx to still maintain good performance in the face of high concurrency.
2. Reverse proxy server cluster:
   Nginx supports cluster deployment of reverse proxy servers. By horizontally expanding multiple Nginx instances, the availability and pressure resistance of the system can be improved. A reverse proxy server cluster can distribute requests across multiple servers to achieve load balancing.

2. Traffic diversion policy control method

1. Polling strategy:
   Polling strategy is the most basic and commonly used load balancing strategy, which will Distributed to each server in turn to achieve the effect of balanced request distribution. In the Nginx configuration, you can use the upstream directive to define a group of servers, and use the server directive to set a weight value for each server to control the traffic proportion of each server. For example:

http {
  upstream backend {
    server backend1.example.com weight=3;
    server backend2.example.com weight=2;
    server backend3.example.com;
  }
  
  server {
    location / {
      proxy_pass http://backend;
    }
  }
}

In the above configuration, Nginx will distribute requests to the three backend servers according to weight values, among which the traffic of backend1.example.com will be# 1.5 times of ##backend2.example.com.

IP hash policy:
2. The IP hash policy will allocate requests to specified servers based on the client's IP address. This strategy is suitable for situations where state needs to be maintained across user sessions, such as shopping carts or user login information. In the Nginx configuration, you can use the
   ip_hash directive to enable the IP hash policy. For example:

http {
  upstream backend {
    ip_hash;
    server backend1.example.com;
    server backend2.example.com;
    server backend3.example.com;
  }
  
  server {
    location / {
      proxy_pass http://backend;
    }
  }
}

In the above configuration, Nginx will calculate the client's IP address and allocate requests from the same client to the same server to maintain the consistency of user session status.

Minimum number of connections policy:
3. The minimum number of connections policy will allocate requests to the server with the least number of connections to achieve load balancing. In the Nginx configuration, you can use the
   least_conn directive to enable the minimum number of connections policy. For example:

http {
  upstream backend {
    least_conn;
    server backend1.example.com;
    server backend2.example.com;
    server backend3.example.com;
  }
  
  server {
    location / {
      proxy_pass http://backend;
    }
  }
}

In the above configuration, Nginx will distribute requests to the server with the smallest number of connections to maintain server load balancing.
Summary:

As a high-performance reverse proxy server, Nginx has excellent scalability and traffic diversion policy control methods. Through the asynchronous event-driven processing model and the deployment of reverse proxy server clusters, application scenarios with high traffic and large-scale access can be easily handled. At the same time, through various load balancing strategies such as polling, IP hashing, and minimum number of connections, balanced distribution of traffic can be achieved and system availability and performance can be improved.


(Note: The above is just a brief introduction to the high scalability and traffic diversion strategy of the Nginx reverse proxy server. In actual applications, more detailed configuration and optimization are required according to specific needs.)

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