Strategy of Load Balancing Implemented by Nginx

One: Introduction to nginx

nginx is a high-performance HTTP server and reverse proxy server. It was initially developed by Russian Igor Sysoev and still supports many large Russian websites.

Two: Three Load Balancing Strategies Supported by nginx

Round Robin: Send requests sequentially to each server.

Least Connections: Send requests to the server that holds the fewest active connections.

IP Hash: Determines which server the request is sent to by means of a hash function.

Weight: The higher the weight of the server, the greater the probability of handling requests.

Three: Round Robin Load Balancing

Add the following configuration to the nginx.conf configuration file, which provides payment services with three servers.

http {
 upstream CashServers {
  server CashServers1.com;
  server CashServers2.com;
  server CashServers3.com;
 }
 server {
  listen 80;
  location / {
   proxy_pass http://CashServers;
  }
 }
}

. Pay attention to the following points

1The default configuration is the round-robin strategy.

2.nginx load balancing supports HTTP and HTTPS protocols, you only need to modify the protocol after proxy_pass.

3.nginx supports load balancing for FastCGI, uwsgi, SCGI, and memcached, simply by changing proxy_pass to fastcgi_pass, uwsgi_pass, scgi_pass, or memcached_pass.

4. This strategy is suitable for servers with similar configurations, stateless, and services that are short, flat, and fast.

4. Least Connections Load Balancing

http {
 upstream CashServers {
  least_conn;
  server CashServers1.com;
  server CashServers2.com;
  server CashServers3.com;
 }
 server {
  listen 80;
  location / {
   proxy_pass http://CashServers;
  }
 }
}

. Pay attention to the following points

1. Least connections load balancing is defined using the least_conn directive;

2. This load balancing strategy is suitable for situations where the server is overloaded due to requests with different processing times;

5. IP Hash Load Balancing

http {
 upstream CashServers {
  ip_hash;
  server CashServers1.com;
  server CashServers2.com;
  server CashServers3.com;
 }
 server {
  listen 80;
  location / {
   proxy_pass http://CashServers;
  }
 }
}

. Pay attention to the following points

1. ip hash load balancing is defined using the ip_hash directive;

2. nginx uses the IP address of the request client for hash calculation to ensure that the same server responds to the request;

3. This strategy is suitable for stateful services, such as session;

6. Weight-based Load Balancing

http {
 upstream CashServers {  
  server CashServers1.com weight=3;
  server CashServers2.com weight=2;
  server CashServers3.com weight=1;
 }
 server {
  listen 80;
  location / {
   proxy_pass http://CashServers;
  }
 }
}

. Pay attention to the following points

1. Weight-based load balancing requires the use of the weight directive to define;

2. The higher the weight, the more requests are allocated to the server that needs to be processed;

3. This strategy can be combined with the least connections load and ip hash strategies;

4. This strategy is more suitable for server hardware configurations with large differences;

7. Health Check

nginx has built-in health check mechanisms for servers. If a specific server request fails, nginx can mark it for the next time so that it will not be assigned to it again. max_fails defines the number of times to mark the server as unavailable after a specified number of failures.

That's all for this article. I hope it will be helpful to everyone's learning and that everyone will support the Yelling Tutorial more.

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