Notes about things

A collection of my notes. Provided as is with no warranty of any kind expressed or implied.

Installing and using PM2

PM2 is a process manager for Node.js applications. It provides an easy way to run them in the background as a service.

Install

sudo npm install -g pm2

Manage an application with PM2

Use the pm2 start command to run your application

pm2 start hello-world.js

This also adds your application to PM2's process list, which is outputted every time you start an application:

To get more details about a running app use the pm2 show command

pm2 show <id|name>

PM2 automatically assigns an App name (based on the filename, without the .js extension) and a PM2 id. PM2 also maintains other information, such as the PID of the process, its current status, and memory usage.

If an application running under PM2 crashes or is killed it will automatically restart. To have an application launch on system startup use the pm2 startup command

pm2 startup systemd

The last line of the resulting output includes a command that must be run with superuser privileges

Other PM2 commands

Stop an application

pm2 stop <id|name>

Restart an application

pm2 restart <id|name>

List applications currently managed by PM2

pm2 list

More information about a specific application

pm2 info <id|name>

The PM2 process monitor can be pulled up with the monit subcommand. This displays the application status, CPU, and memory usage:

pm2 monit