`pm2-runtime` stuck on launching with cluster mode, but worked fine with fork mode...

What's going wrong?

My ecosystem.config.js:

module.exports = {
  apps: [{
    script: './node_modules/.bin/ts-node',
    args: '-r ./node_modules/tsconfig-paths/register ./server/server.js',
    cwd: './',
    name: 'jpk-web-v3',
    env: {
      'NODE_ENV': 'development'
    },
    env_production: {
      'NODE_ENV': 'production'
    },
    exec_mode: 'cluster',
    instances: 2
  }]
}

After pm2-runtime path/to/ecosystem.config.js --env production, the process logged information below:

2021-01-19T11:41:04: PM2 log: Launching in no daemon mode
2021-01-19T11:41:04: PM2 log: App [jpk-web-v3:0] starting in -cluster mode-
2021-01-19T11:41:04: PM2 log: App [jpk-web-v3:0] online
2021-01-19T11:41:04: PM2 log: App [jpk-web-v3:1] starting in -cluster mode-
2021-01-19T11:41:04: PM2 log: App [jpk-web-v3:1] online

Then stuck on this situation, normally it should run some build log.

But all things work with fork mode:

Try to start server on port 81:
- Waiting...
Server start successfully at：http://localhost:81

Supporting information

--- PM2 report ----------------------------------------------------------------
Date                 : Tue Jan 19 2021 11:42:10 GMT+0800 (China Standard Time)
===============================================================================
--- Daemon -------------------------------------------------
pm2d version         : 4.5.0
node version         : 14.14.0
node path            : /usr/local/bin/pm2
argv                 : /Users/zhangyongchao/.nvm/versions/node/v14.14.0/bin/node,/Users/zhangyongchao/.config/yarn/global/node_modules/pm2/lib/Daemon.js
argv0                : node
user                 : zhangyongchao
uid                  : 501
gid                  : 20
uptime               : 0min
===============================================================================
--- CLI ----------------------------------------------------
local pm2            : 4.5.0
node version         : 14.14.0
node path            : /usr/local/bin/pm2
argv                 : /Users/zhangyongchao/.nvm/versions/node/v14.14.0/bin/node,/usr/local/bin/pm2,report
argv0                : node
user                 : zhangyongchao
uid                  : 501
gid                  : 20
===============================================================================
--- System info --------------------------------------------
arch                 : x64
platform             : darwin
type                 : Darwin
cpus                 : Intel(R) Core(TM) i7-7700HQ CPU @ 2.80GHz
cpus nb              : 8
freemem              : 586412032
totalmem             : 17179869184
home                 : /Users/zhangyongchao
===============================================================================
--- PM2 list -----------------------------------------------
┌─────┬───────────┬─────────────┬─────────┬─────────┬──────────┬────────┬──────┬───────────┬──────────┬──────────┬──────────┬──────────┐
│ id  │ name      │ namespace   │ version │ mode    │ pid      │ uptime │ ↺    │ status    │ cpu      │ mem      │ user     │ watching │
└─────┴───────────┴─────────────┴─────────┴─────────┴──────────┴────────┴──────┴───────────┴──────────┴──────────┴──────────┴──────────┘
===============================================================================
--- Daemon logs --------------------------------------------
/Users/zhangyongchao/.pm2/pm2.log last 20 lines:
PM2        | 2021-01-19T11:26:28: PM2 log: Concurrent actions   : 2
PM2        | 2021-01-19T11:26:28: PM2 log: SIGTERM timeout      : 1600
PM2        | 2021-01-19T11:26:28: PM2 log: ===============================================================================
PM2        | 2021-01-19T11:40:58: PM2 log: PM2 successfully stopped
PM2        | 2021-01-19T11:42:10: PM2 log: ===============================================================================
PM2        | 2021-01-19T11:42:10: PM2 log: --- New PM2 Daemon started ----------------------------------------------------
PM2        | 2021-01-19T11:42:10: PM2 log: Time                 : Tue Jan 19 2021 11:42:10 GMT+0800 (China Standard Time)
PM2        | 2021-01-19T11:42:10: PM2 log: PM2 version          : 4.5.0
PM2        | 2021-01-19T11:42:10: PM2 log: Node.js version      : 14.14.0
PM2        | 2021-01-19T11:42:10: PM2 log: Current arch         : x64
PM2        | 2021-01-19T11:42:10: PM2 log: PM2 home             : /Users/zhangyongchao/.pm2
PM2        | 2021-01-19T11:42:10: PM2 log: PM2 PID file         : /Users/zhangyongchao/.pm2/pm2.pid
PM2        | 2021-01-19T11:42:10: PM2 log: RPC socket file      : /Users/zhangyongchao/.pm2/rpc.sock
PM2        | 2021-01-19T11:42:10: PM2 log: BUS socket file      : /Users/zhangyongchao/.pm2/pub.sock
PM2        | 2021-01-19T11:42:10: PM2 log: Application log path : /Users/zhangyongchao/.pm2/logs
PM2        | 2021-01-19T11:42:10: PM2 log: Worker Interval      : 30000
PM2        | 2021-01-19T11:42:10: PM2 log: Process dump file    : /Users/zhangyongchao/.pm2/dump.pm2
PM2        | 2021-01-19T11:42:10: PM2 log: Concurrent actions   : 2
PM2        | 2021-01-19T11:42:10: PM2 log: SIGTERM timeout      : 1600
PM2        | 2021-01-19T11:42:10: PM2 log: ===============================================================================

Start by reproducing the issue with the shown ecosystem.config.js and the pm2-runtime command, comparing cluster mode with the working fork mode. Review the PM2 report and daemon logs for the launch path; done means cluster mode starts the application and produces the expected server startup logs.