Port address already in use error.

[htmlObserver]

I'm reading the documentation but can not find what requirements does an application need to meet in order to be managed by PM2 in cluster mode?

I'm trying to run 'gatsby serve' in cluster mode, but when attempting to 'reload' the application, I see errors in the logs related to the port already being in use:

Error: listen EADDRINUSE: address already in use 127.0.0.1:9000
    at Server.setupListenHandle [as _listen2] (node:net:1330:16)
    at listenInCluster (node:net:1378:12)
    at GetAddrInfoReqWrap.doListen (node:net:1516:7)
    at GetAddrInfoReqWrap.onlookup [as oncomplete] (node:dns:73:8)
Emitted 'error' event on Server instance at:
    at emitErrorNT (node:net:1357:8)
    at processTicksAndRejections (node:internal/process/task_queues:83:21) {
  code: 'EADDRINUSE',
  errno: -98,
  syscall: 'listen',
  address: '127.0.0.1',
  port: 9000
}

The application doesn't start after reload command, but PM2 shows the status as "online," which is incorrect.

[ifty64bit]

I am also facing the same issue. I had to reload with id manually.

[naegelin]

There is a good example on how to use cluster mode here: https://medium.com/@manikmudholkar831995/clustering-and-pm2-multitasking-in-nodejs-c6b10249cfd4

[Crane04]

I'm having this issue too