{
	"apps": [{
		"name": "rocket.chat",
		"exec_mode": "fork_mode",
		"max_memory_restart": "400M",
		"log_date_format": "YYYY-MM-DD HH:mm:ss SSS",
		"script": "/var/www/rocket.chat/bundle/main.js",
		"out_file": "/var/log/rocket.chat/app.log",
		"error_file": "/var/log/rocket.chat/err.log",
		"port": "80",
		"env": {
			"CDN_PREFIX": "//dbde4sd21oahf.cloudfront.net",
			"MONGO_URL": "mongodb://localhost:27017/rocketchat",
			"MONGO_OPLOG_URL": "mongodb://localhost:27017/local",
			"ROOT_URL": "http://rocket.chat",
			"PORT": "80"
		}
	}]
}

{
	"apps": [{
		"name": "rocket.chat",
		"exec_mode": "cluster",
		"instances" : 0,
		"max_memory_restart": "400M",
		"log_date_format": "YYYY-MM-DD HH:mm:ss SSS",
		"script": "/var/www/rocket.chat/bundle/main.js",
		"out_file": "/var/log/rocket.chat/app.log",
		"error_file": "/var/log/rocket.chat/err.log",
		"port": "80",
		"env": {
			"CDN_PREFIX": "//dbde4sd21oahf.cloudfront.net",
			"MONGO_URL": "mongodb://localhost:27017/rocketchat",
			"MONGO_OPLOG_URL": "mongodb://localhost:27017/local",
			"ROOT_URL": "http://rocket.chat",
			"PORT": "80"
		}
	}]
}

Change deploy to cluster mode
Change deploy to cluster mode
