PM2 app manager

PM2 application manager

Use NPM To Install A Package Called PM2.

NPM is a package manager that you will use to install frameworks and libraries to use with your Node.js applications. NPM was installed with Node.js. PM2 is a sweet little tool that is going to solve two problems for you:

1. It is going to keep your site up by restarting the application if it crashes. These crashes should NOT happen, but it is good know that PM2 has your back. (Some people may be aware of Forever.js, another tool that is used to keep node based sites running - I think you will find that PM2 has a lot to offer.)

2. It is going to help you by restarting your node application as a service every time you restart the server. Some of use know of other ways to do this, but pm2 makes it easier, and it has some added flexibility.
   Install PM2 by typing the following at the command line:
   
   sudo npm install pm2 -g
   
   From <https://www.digitalocean.com/community/tutorials/how-to-use-pm2-to-setup-a-node-js-production- environment-on-an-ubuntu-vps>
   

Pm2-logrotate

Install pm2-logrotate to manage pm2 logs:

https://www.npmjs.com/package/pm2-logrotate

To make changes to pm2-logrotate configuration file, you'll have to go to: /.pm2/module_config.json

Cheatsheet

# Fork mode

pm2 start app.js --namemy-api # Name process# Cluster mode

pm2 start app.js -i0 # Will start maximum processes with LB depending on available CPUs

pm2 start app.js -imax # Same as above, but deprecated.

pm2 scale app +3 # Scales `app` up by 3 workers

pm2 scale app 2 # Scales `app` up or down to 2 workers total# Listing

pm2 list # Display all processes status

pm2 jlist # Print process list in raw JSON

pm2 prettylist # Print process list in beautified JSON

pm2 describe 0 # Display all informations about a specific process

pm2 monit # Monitor all processes# Logs

pm2 logs [--raw] # Display all processes logs in streaming

pm2 flush # Empty all log files

pm2 reloadLogs # Reload all logs# Actions

pm2 stop all # Stop all processes

pm2 restart all # Restart all processes

pm2 reload all # Will 0s downtime reload (for NETWORKED apps)

pm2 stop 0 # Stop specific process id

pm2 restart 0 # Restart specific process id

pm2 delete 0 # Will remove process from pm2 list

pm2 delete all # Will remove all processes from pm2 list# Misc

pm2 reset <process> # Reset meta data (restarted time...)

pm2 updatePM2 # Update in memory pm2

pm2 ping # Ensure pm2 daemon has been launched

pm2 sendSignal SIGUSR2 my # Send system signal to script

pm2 start app.js --no-daemon

pm2 start app.js --no-vizion

pm2 start app.js --no-autorestart

From <https://pm2.keymetrics.io/docs/usage/quick-start/>

Pm2 and memory usage

https://jsantacl.medium.com/pm2-and-memory-usage-in-node-js-apps-fd17394fcb40