Node.js Cluster Module Cluster Example
Example
A single instance of Node.js runs in a single thread. To take advantage of multi-core systems, application can be launched in a cluster of Node.js processes to handle the load.
The cluster module allows you to easily create child processes that all share server ports.
Following example create the worker child process in main process that handles the load across multiple cores.
Example
const cluster = require('cluster');
const http = require('http');
const numCPUs = require('os').cpus().length; //number of CPUS
if (cluster.isMaster) {
// Fork workers.
for (var i = 0; i < numCPUs; i++) {
cluster.fork(); //creating child process
}
//on exit of cluster
cluster.on('exit', (worker, code, signal) => {
if (signal) {
console.log(`worker was killed by signal: ${signal}`);
} else if (code !== 0) {
console.log(`worker exited with error code: ${code}`);
} else {
console.log('worker success!');
}
});
} else {
// Workers can share any TCP connection
// In this case it is an HTTP server
http.createServer((req, res) => {
res.writeHead(200);
res.end('hello world\n');
}).listen(3000);
}
