The cluster module allows creating child processes (workers) that share server ports, enabling a multi-core system to handle higher application workloads.

PM2 wraps Node.js core cluster module under the hood, managing process lifecycles, health monitoring, load balancing, and dynamic scaling through simple configurations.

PM2 is a production process manager for Node.js. It handles automatic application restarts on failures, application clustering, zero-downtime reloads, and log management.

Listen for termination signals (SIGTERM, SIGINT), stop accepting new incoming requests using server.close(), complete pending requests, close active database pools, and exit the process.

When spawning child processes using child_process.fork(), an IPC channel is established. To cleanly disconnect without abruptly killing ongoing tasks, call child.disconnect(). This closes the IPC channel, allows pending events to drain, and permits the child process to exit naturally once its event loop completes.

Node.js supports bundling application code and assets directly into a single executable binary (SEA). Introduced natively in modern Node.js releases, SEA allows distributing Node.js applications as standalone executable binaries without requiring users to install the Node.js runtime environment separately on host targets.

Node.js v18.11+ introduced a native file watching flag --watch. When started with node --watch app.js, Node.js monitors imported dependency files and automatically restarts the process whenever changes are saved, removing the need for external CLI dependencies like nodemon or pm2-dev during local development.