pm2 constantly leaking memory when running app in cluster mode

Question

Currently, running my prod apps in cluster mode with pm2 to create multiple instances. But over time, I can see increase in memory usage. How to solve it as for ow I need to restart the app manually?

pm2 start app.js -i 0 -o "/dev/null"

Answer 1

You can either:

• figure out where the memory leak in your app is and fix that, or
• set the --max-memory-restart option to have pm2 restart instances of your app when they leak too much

Answer 2

I was facing the same issue. It's because pm2 has an issue with the memory leak.

Instead use nodejs cluster module.

const cluster = require('cluster')

require('events').EventEmitter.defaultMaxListeners = Infinity;
const OS = require('os');
process.env.UV_THREADPOOL_SIZE = OS.cpus().length


let app = express();


const numCPUs = parseInt(process.env.NO_OF_CPU || 1)

if(cluster.isMaster) {
  for (var i = 0; i < numCPUs; i++) {
    cluster.fork();
  }
} else {
  // start server on port
  let appServer = app.listen(process.env.OUTBOUND_PORT, () => {
    console.log(`server listening on ${process.env.OUTBOUND_PORT} `);
  });
}