Node.js runs on a single thread, so all the processes are only able to use a single thread at any given time. For scaling Node.js applications and using the multi-core systems, there are two ways you can go about it.
What are the Different Type of Scaling in Node.js Applications?
1. Clustering (Vertical Scaling):
The built-in cluster module in Node.js allows you to create multiple child processes (workers) that all share the same server port. A master process listens for connections and distributes them to the worker processes. This allows your application to utilize all the available CPU cores on a single machine.
Tools:
While you can use the cluster module directly, it’s much easier to use a process manager like PM2 (Process Manager 2). With a simple command, PM2 will automatically set up a cluster using all available CPU cores and also handle monitoring, logging, and automatic restarts if a process crashes.
2. Microservices (Horizontal Scaling):
This is an architectural approach where you break your large monolithic application into a collection of smaller, independent services. All standalone services are responsible for a specific business capability (e.g., user service, payment service, notification service).
How it works:
You run multiple instances of your Node.js application (or different services) across multiple machines. A load balancer (like Nginx, HAProxy, or a cloud provider’s load balancer) sits in front of these instances and distributes incoming traffic among them.
Advantages: This approach offers high availability (if one machine goes down, others are still running), independent scaling (you can add more servers for the payment service if it’s under heavy load), and technology diversity (one service could be in Node.js, another in Go).
Final Words
In a real-world production environment, you typically use a combination of both. You use PM2 to vertically scale the application on each server (utilizing all its cores), and then you use a load balancer to horizontally scale across multiple servers. And if you’re not sure how to implement it right, it’s a good time to hire Node.js developers who’ve worked on scaling complex systems in real-world environments.
