PM2 is a General Purpose Process Manager and a Production Runtime for Node.js apps with a built-in Load Balancer.
- Simple and efficient process management (start/stop/restart/delete/show/monit)
- Keep your application ALWAYS ONLINE with auto restarts and init system script generation
- Clusterize Node.js Applications without code change to increase performance and reliability
- Hot Reload Node.js Applications without extra configuration
Starting an application in production mode is as easy as:
$ pm2 start app.js
PM2 is constantly assailed by more than 1800 tests.
Official website: http://pm2.keymetrics.io/
Works on Linux (stable) & macOS (stable) & Windows (stable). All Node.js versions are supported starting Node.js 0.12.
$ npm install pm2 -g
npm is a builtin CLI when you install Node.js - Installing Node.js with NVM
Start an application
You can start any application (Node.js, Python, Ruby, binaries in $PATH...) like that:
$ pm2 start app.js
Your app is now daemonized, monitored and kept alive forever.
With the drop-in replacement command for
pm2-runtime, run your Node.js application in a proper production environment.
There is also an officialy supported Docker image.
Using it is seamless:
FROM keymetrics/pm2:latest-alpine [...] CMD [ "pm2-runtime", "npm", "--", "start" ]
Managing a Process
Once applications are started you can manage them easily:
To list all running processes:
$ pm2 list
Managing processes is straightforward:
$ pm2 stop <app_name|id|'all'|json_conf>$ pm2 restart <app_name|id|'all'|json_conf>$ pm2 delete <app_name|id|'all'|json_conf>
To have more details on a specific process:
$ pm2 describe <id|app_name>
To monitor logs, custom metrics, process information:
$ pm2 monit
Cluster Mode: Node.js Load Balancing & Hot Reload
The Cluster mode is a special mode when starting a Node.js application, it starts multiple processes and load-balance HTTP/TCP/UDP queries between them. This increase overall performance (by a factor of x10 on 16 cores machines) and reliability (faster socket re-balancing in case of unhandled errors).
Starting a Node.js application in cluster mode that will leverage all CPUs available:
$ pm2 start api.js -i <processes>
<processes> can be
-1 (all cpu minus 1) or a specified number of instances to start.
Hot Reload allows to update an application without any downtime:
$ pm2 reload all
Seamlessly supported by all major Node.js frameworks and any Node.js applications without any code change:
Terminal Based Monitoring
Monitor all processes launched straight from the command line:
$ pm2 monit
Monitor PM2 and Applications with our SaaS
Once you deploy your application in production, you can monitor, debug and profile it externally with our SaaS Monitoring.
To start monitoring applications from the terminal:
$ pm2 register
Expose Custom Metrics
To get more insights on how your application behave, plug custom metrics inside your code and monitor them with the
pm2 monit command:
In your project install pmx:
$ npm install pmx --save
Then plug a custom metric:
var Probe = ;var counter = 1;var metric = Probe;;
Then to see the metric type from in the terminal:
$ pm2 monitor
Metric, Counter, Histogram and Meters are available
Displaying logs of a specified process or all processes, in real time is easy:
$ pm2 logs ['all'|app_name|app_id] [--json] [--format] [--raw]
Standard, Raw, JSON and formated output are available.
$ pm2 logs APP-NAME # Display APP-NAME logs$ pm2 logs --json # JSON output$ pm2 logs --format # Formated output$ pm2 flush # Flush all logs$ pm2 reloadLogs # Reload all logs
Startup script generation
PM2 can generates and configure a startup script to keep PM2 and your processes alive at every server restart.
Supports init systems like: systemd (Ubuntu 16, CentOS, Arch), upstart (Ubuntu 14/12), launchd (MacOSx, Darwin), rc.d (FreeBSD).
# Auto detect init system + generate and setup PM2 boot at server startup$ pm2 startup# Manually specify the startup system# Can be: systemd, upstart, launchd, rcd$ pm2 startup [platform]# Disable and remove PM2 boot at server startup$ pm2 unstartup
To save/freeze a process list on reboot:
$ pm2 save
# General$ npm install pm2 -g # Install PM2$ pm2 start app.js # Start, Daemonize and auto-restart application (Node)$ pm2 start app.py # Start, Daemonize and auto-restart application (Python)$ pm2 start npm -- start # Start, Daemonize and auto-restart Node application# Cluster Mode (Node.js only)$ pm2 start app.js -i 4 # Start 4 instances of application in cluster mode# it will load balance network queries to each app$ pm2 reload all # Zero Second Downtime Reload$ pm2 scale [app-name] 10 # Scale Cluster app to 10 process# Process Monitoring$ pm2 list # List all processes started with PM2$ pm2 list --sort=<field> # Sort all processes started with PM2$ pm2 monit # Display memory and cpu usage of each app$ pm2 show [app-name] # Show all information about application# Log management$ pm2 logs # Display logs of all apps$ pm2 logs [app-name] # Display logs for a specific app$ pm2 logs --json # Logs in JSON format$ pm2 flush$ pm2 reloadLogs# Process State Management$ pm2 start app.js --name="api" # Start application and name it "api"$ pm2 start app.js -- -a 34 # Start app and pass option "-a 34" as argument$ pm2 start app.js --watch # Restart application on file change$ pm2 start script.sh # Start bash script$ pm2 start app.json # Start all applications declared in app.json$ pm2 reset [app-name] # Reset all counters$ pm2 stop all # Stop all apps$ pm2 stop 0 # Stop process with id 0$ pm2 restart all # Restart all apps$ pm2 gracefulReload all # Gracefully reload all apps in cluster mode$ pm2 delete all # Kill and delete all apps$ pm2 delete 0 # Delete app with id 0# Startup/Boot management$ pm2 startup # Detect init system, generate and configure pm2 boot on startup$ pm2 save # Save current process list$ pm2 resurrect # Restore previously saved processes$ pm2 unstartup # Disable and remove startup system$ pm2 update # Save processes, kill PM2 and restore processes$ pm2 init # Generate a sample js configuration file# Deployment$ pm2 deploy app.json prod setup # Setup "prod" remote server$ pm2 deploy app.json prod # Update "prod" remote server$ pm2 deploy app.json prod revert 2 # Revert "prod" remote server by 2# Module system$ pm2 module:generate [name] # Generate sample module with name [name]$ pm2 install pm2-logrotate # Install module (here a log rotation system)$ pm2 uninstall pm2-logrotate # Uninstall module$ pm2 publish # Increment version, git push and npm publish
Also check out the example folder to discover all features.
# 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 embeds a simple and powerful module system. Installing a module is straightforward:
$ pm2 install <module_name>
Here are some PM2 compatible modules (standalone Node.js applications managed by PM2):
If you manage your NodeJS app with PM2, Keymetrics makes it easy to monitor and manage apps across servers. Feel free to try it:
Thanks in advance and we hope that you like PM2!
More about PM2
- Application Declaration via JS files
- Watch & Restart
- PM2 API
- Deployment workflow
- PM2 on Heroku/Azure/App Engine
- PM2 auto completion
- Using PM2 in ElasticBeanStalk
- PM2 Tutorial Series
PM2 is made available under the terms of the GNU Affero General Public License 3.0 (AGPL 3.0). We can deliver other licenses, for more informations contact sales.
- fault tolerant
- load balancer
- source maps
- node.js monitoring
- ghost production
- process manager
- keep process alive
- process configuration
- cluster cli
- dev ops