pm2 README

The project's README from github.com/Unitech/pm2. As one markdown file: README.md.


PM2

P(rocess) M(anager) 2
Runtime Edition

Downloads per Month Downloads per Year npm version


PM2 is a production process manager for Node.js/Bun applications with a built-in load balancer. It allows you to keep applications alive forever, to reload them without downtime and to facilitate common system admin tasks.

Starting an application in production mode is as easy as:

$ pm2 start app.js

PM2 is battle-tested by a comprehensive test suite.

Official website: https://pm2.keymetrics.io/

Works on Linux, macOS, and Windows. Supports Node.js 18+ and Bun 1+.

Installing PM2

With NPM

$ npm install pm2 -g

With Bun

$ bun install pm2 -g

If you only have Bun installed (no Node.js), symlink node to bun so PM2's #!/usr/bin/env node shebang resolves to Bun's node-compatibility runtime:

$ sudo ln -s $(which bun) /usr/local/bin/node

You can install Node.js easily with NVM or FNM or install Bun with curl -fsSL https://bun.sh/install | bash

Start an application

You can start any application (Node.js, Bun, and also Python, Ruby, binaries in $PATH...) like that:

$ pm2 start app.js
$ pm2 start app.ts
$ pm2 start app.py

Your app is now daemonized, monitored and kept alive forever.

Managing Applications

Once applications are started you can manage them easily:

Process listing

To list all running applications:

$ pm2 list

Managing apps is straightforward:

$ pm2 stop     <app_name|namespace|id|'all'|json_conf>
$ pm2 restart  <app_name|namespace|id|'all'|json_conf>
$ pm2 delete   <app_name|namespace|id|'all'|json_conf>

To have more details on a specific application:

$ pm2 describe <id|app_name>

To monitor logs, custom metrics, application information:

$ pm2 monit

More about Process Management

Cluster Mode: Node.js Load Balancing & Zero Downtime Reload

Cluster mode starts multiple Node.js processes and load-balances HTTP/TCP/UDP queries between them. This significantly increases throughput on multi-core machines and improves reliability (faster socket re-balancing in case of unhandled errors).

Framework supported

Starting a Node.js application in cluster mode that will leverage all CPUs available:

$ pm2 start api.js -i <processes>

<processes> can be 'max', -1 (all cpu minus 1) or a specified number of instances to start.

Zero Downtime Reload

Hot Reload allows you to update an application without any downtime:

$ pm2 reload all

More information about how PM2 makes clustering easy

Container Support

With the drop-in replacement command for node, called pm2-runtime, run your Node.js application in a hardened production environment. Using it is seamless:

RUN npm install pm2 -g
CMD [ "pm2-runtime", "npm", "--", "start" ]

Read More about the dedicated integration

Terminal Based Monitoring

Monit

Monitor all processes launched straight from the command line:

$ pm2 monit

Log Management

To consult logs just type the command:

$ pm2 logs

Standard, Raw, JSON and formatted output are available.

Examples:

$ pm2 logs APP-NAME       # Display APP-NAME logs
$ pm2 logs --json         # JSON output
$ pm2 logs --format       # Formatted output

$ pm2 flush               # Flush all logs
$ pm2 reloadLogs          # Reload all logs

To enable log rotation install the following module

$ pm2 install pm2-logrotate

More about log management

Startup Scripts Generation

PM2 can generate and configure a Startup Script to keep PM2 and your processes alive at every server restart.

Init Systems Supported: systemd, upstart, systemv, openrc, launchd, rcd, rcd-openbsd, smf

# Generate Startup Script
$ pm2 startup

# Freeze your process list across server restart
$ pm2 save

# Remove Startup Script
$ pm2 unstartup

More about Startup Scripts Generation

Updating PM2

# Install latest PM2 version
$ npm install pm2@latest -g
# Save process list, exit old PM2 & restore all processes
$ pm2 update

PM2 updates are seamless

PM2+ Monitoring

If you manage your apps with PM2, PM2+ makes it easy to monitor and manage apps across servers.

https://app.pm2.io/

Feel free to try it:

Discover the monitoring dashboard for PM2

Thanks in advance and we hope that you like PM2!

CHANGELOG

CHANGELOG

Contributors

Contributors

License

PM2 is made available under the terms of the GNU Affero General Public License 3.0 (AGPL 3.0). For other licenses contact us.

pm2 (Unitech/pm2)

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43.3K ·GitHub
Pm2
What is this?PM2 is a production process manager for Node.js and Bun applications that keeps them running forever, reloads them without downtime, and includes a built-in load balancer.
Is this a library I import, or a standalone CLI tool?It's a standalone CLI tool you run alongside your app, not a library you import into code. You install it globally and use commands like pm2 start to manage your processes.
How do I get an app running under PM2?Install it with npm, then run pm2 start on your app's entry file (Node.js, Bun, Python, Ruby, or any binary in $PATH); it immediately daemonizes and keeps the app alive.
Do I need Node.js or can I run it with just Bun?PM2 requires Node.js 18+ or Bun 1+; if you only have Bun installed, you need to symlink node to bun so PM2's node shebang resolves correctly.
Does cluster mode work for any kind of app?Cluster mode is specifically for Node.js apps and load-balances HTTP/TCP/UDP across multiple processes using all CPUs; apps in other languages run as regular single-process managed apps instead.
Which operating systems does it run on?PM2 works on Linux, macOS, and Windows.
What is the PM2+ hosted dashboard, and is it optional?PM2+ is a separate hosted monitoring and management dashboard for apps run with PM2 across servers; it's an optional add-on, not required to use PM2 itself.
Can PM2 restart my apps automatically after a server reboot?Yes, it can generate a Startup Script for systemd, upstart, systemv, openrc, launchd, and other init systems so PM2 and your processes relaunch on every server restart.
How do I monitor logs and CPU/memory from the terminal?PM2 includes a built-in terminal-based monitoring view and log commands that support standard, raw, JSON, and formatted log output.
Can PM2 be used inside Docker containers?Yes, PM2 provides a drop-in replacement command for node called pm2-runtime designed to run Node.js apps in a hardened container production environment.
What does zero-downtime reload mean in PM2?In cluster mode, PM2 can hot-reload an updated app by restarting its worker processes one at a time, so the app keeps serving requests without any downtime.
What are similar projects?forever, nexe, spug, nodemon, webhook, deployer, shelljs, lsoff
Which topics is it in?process-manager, production, deploy, load-balancer, node, sysadmin, agpl, monitoring, command-line, devops, command-line-tool, terminal
Creator
Unitech
Size
14.1 MB
Stars
43.3K
Updated
CommitAug 24Releasev7.0.4Aug 24
Age
13y
Commits · 90 Days