What is the difference between cluster and worker_threads packages in Node.js?

In Node.js, the cluster and worker_threads packages are both used to handle tasks concurrently, but they operate at different levels of the system and are suited for different types of tasks.

Cluster

The cluster module in Node.js allows you to create multiple instances of your application running on separate processes. This is particularly useful for taking full advantage of multi-core CPUs, as each instance can run on its own CPU core. The primary use of the cluster module is to improve the ability of an application to handle a large number of incoming network requests by distributing these requests across multiple worker processes. Each worker process runs in its own Node.js runtime, and the master process manages the distribution of requests and the spawning of these worker processes.

Key characteristics of the cluster module include:

• Load Balancing: The master process listens on a port and distributes incoming connections to worker processes in a round-robin fashion, although this can be customized[3][7].
• Fault Tolerance: If a worker process crashes, the master process can spawn a new one, which helps in maintaining the application's availability without downtime[3][7].
• Separate Memory Space: Each worker process has its own V8 instance and memory space, which increases memory usage but provides isolation between processes[3].

Worker Threads

The worker_threads module, on the other hand, allows you to run JavaScript in parallel within the same process. This is achieved by spawning multiple threads, each capable of executing JavaScript concurrently with the main thread. This is suitable for performing CPU-intensive tasks without blocking the main thread that handles I/O operations.

Key characteristics of worker threads include:

• Shared Memory Space: Worker threads can share mem...