PM2 is straightforward, it is offered as a simple and intuitive CLI, installable via NPM. Just start your application with PM2 to boost your application and to make it ready to handle a ton of traffic!

Installation

The latest PM2 stable version is installable via NPM:

npm install pm2@latest -g

Above will install the latest version and if its running then you need update the in-memory version by running following command

pm2 update

Usage

The simplest way to start, daemonize and monitor your application is by using this command line:

pm2 start app.js

Application declaration

You can also create a configuration file to manage multiple applications:

process.yml:

apps:
  - script   : app.js
    instances: 4
    exec_mode: cluster
  - script : worker.js
    watch  : true
    env    :
      NODE_ENV: development
    env_production:
      NODE_ENV: production

And start it easily:

pm2 start process.yml

Read more about application declaration here.

Setup startup script

Restarting PM2 with the processes you manage on server boot/reboot is critical. To solve this, just run this command to generate an active startup script:

pm2 startup

Stop PM2 process

pm2 kill

Stop an instance running under PM2

pm2 stop <<instance_id>>

pm2 stop 0

If you want to stop all running instances

pm2 stop all

Cluster setup

pm2 start server.js -i max

"max" is deprecated and instead of that you can supply 0  pm2 start server.js -i 0

This will roll out maximum number of instance based on no of core available in the server

Supply parameter while initiate an instance

pm2 start server.js -- DEV

In above example, DEV is the parameter value supplied

pm2 start -i 0 server.js -- PARAM1 PARAM2

Above one roll out maximum no of instances based of no of core available and supplying PARAM1 & PARAM2

To display logs (especially the startup logs which includes console.log in express application)

pm2 logs startup

To see metrics & detail of a particular running instance

pm2 show <<instance_id>>

To monitor all running instance with metrics & meta details

pm2 monit

pm2 show 0

To see all environment variable available for the particular instance

pm2 env <<instance_id>>

pm2 env 0