NGINX and PM2: Building elastic application service infrastructure and automatic scaling strategies

NGINX and PM2: Building elastic application service infrastructure and automatic scaling strategies, requiring specific code examples

Introduction:
With cloud computing and virtualization As technology continues to evolve, resiliency and automation have become key elements of modern application service infrastructure. When building an application service architecture that can handle high traffic and load growth, it becomes important to properly select and configure the appropriate tools. This article will introduce two important tools: NGINX and PM2, and provide some code examples to show how to use them to build elastic application service infrastructure and automatic scaling strategies.

1. NGINX: Load Balancing and Reverse Proxy

NGINX is a high-performance HTTP and reverse proxy server that can handle requests from multiple clients and distribute them to multiple clients. on backend servers to achieve load balancing and high availability. The following is a simple NGINX configuration file example:

http {
  upstream backend {
    server backend1.example.com;
    server backend2.example.com;
  }
  
  server {
    listen 80;
    
    location / {
      proxy_pass http://backend;
    }
  }
}

In the above configuration, we created an upstream block named backend, which contains the addresses of multiple backend servers . Then, we use the proxy_pass directive in the default HTTP server block to forward all requests to this upstream block to achieve load balancing.

The advantage of using NGINX as a load balancer is that it can distribute traffic based on various algorithms, such as polling, least connections, IP hashing, etc. In addition, NGINX can also perform health checks. If a backend server fails, it will automatically forward the request to other healthy servers.

2. PM2: Process Management and Automatic Scaling

PM2 is a modern process management tool that can help us manage and monitor the processes of Node.js applications. Here are some commonly used PM2 command examples:

1. Start an application:

   pm2 start app.js

2. Monitor the status of all applications:

   pm2 list

3. Listen for file changes and automatically restart the application:

   pm2 start app.js --watch

4. Set the automatic expansion policy:

   pm2 scale app +4

Above In the code example, we start a Node.js application named app.js and use the --watch option to monitor file changes so that when the file changes Automatically restart the application. In addition, we also used the pm2 scale command to set the automatic scaling policy to increase the number of instances of the application by 4.

PM2 also provides many other useful functions, such as log management, process monitoring and fault recovery, etc. These functions can help us better manage and maintain applications.

3. Integrate NGINX and PM2 to achieve elastic expansion

Now, let us look at how to integrate NGINX and PM2 to achieve elastic expansion in response to high traffic and load growth.

First, we can use NGINX as a load balancer to distribute traffic to multiple PM2 instances. Specifically, we can create an upstream block and list the URLs of multiple PM2 instances within it. We can then use NGINX's load balancing algorithm to distribute traffic.

Secondly, we can use PM2's auto-scaling feature to dynamically increase or decrease the number of instances of the application. For example, when the load increases, we can add more instances by using the pm2 scale command. When the load decreases, we can use the same command to reduce the number of instances. This way, we can automatically expand and contract the capacity of our application as needed.

Finally, we can also use PM2’s monitoring and fault recovery functions to achieve automated operation and maintenance. For example, when a PM2 instance crashes or a problem occurs, PM2 will automatically restart the instance and forward the request to other healthy instances to ensure the availability of the application.

Conclusion:
NGINX and PM2 are important tools for building elastic application service infrastructure and automatic expansion strategies. By using NGINX as a load balancer and reverse proxy, we can achieve traffic distribution and load balancing. By using PM2 as a process management tool, we can achieve automated operation and maintenance and elastic expansion of applications. By integrating NGINX and PM2, we can build a stable, reliable and automatically scalable application service infrastructure.

Appendix: Official documentation link for NGINX and PM2:

• NGINX: https://nginx.org/en/docs/
• PM2: https:/ /pm2.keymetrics.io/docs/

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