How do I run a node.js app as a background service?

Question

Since this post has gotten a lot of attention over the years, I\'ve listed the top solutions per platform at the bottom of this post.

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Original post

Answer 1

Copying my own answer from How do I run a Node.js application as its own process?

2015 answer: nearly every Linux distro comes with systemd, which means forever, monit, PM2, etc are no longer necessary - your OS already handles these tasks.

Make a myapp.service file (replacing 'myapp' with your app's name, obviously):

[Unit]
Description=My app

[Service]
ExecStart=/var/www/myapp/app.js
Restart=always
User=nobody
# Note Debian/Ubuntu uses 'nogroup', RHEL/Fedora uses 'nobody'
Group=nogroup
Environment=PATH=/usr/bin:/usr/local/bin
Environment=NODE_ENV=production
WorkingDirectory=/var/www/myapp

[Install]
WantedBy=multi-user.target

Note if you're new to Unix: /var/www/myapp/app.js should have #!/usr/bin/env node on the very first line.

Copy your service file into the /etc/systemd/system.

Start it with systemctl start myapp.

Enable it to run on boot with systemctl enable myapp.

See logs with journalctl -u myapp

This is taken from How we deploy node apps on Linux, 2018 edition, which also includes commands to generate an AWS/DigitalOcean/Azure CloudConfig to build Linux/node servers (including the .service file).

Answer 2

UPDATE: i updated to include the latest from pm2:

for many use cases, using a systemd service is the simplest and most appropriate way to manage a node process. for those that are running numerous node processes or independently-running node microservices in a single environment, pm2 is a more full featured tool.

https://github.com/unitech/pm2

http://pm2.io

• it has a really useful monitoring feature -> pretty 'gui' for command line monitoring of multiple processes with pm2 monit or process list with pm2 list
• organized Log management -> pm2 logs
• other stuff:

  • Behavior configuration
  • Source map support
  • PaaS Compatible
  • Watch & Reload
  • Module System
  • Max memory reload
  • Cluster Mode
  • Hot reload
  • Development workflow
  • Startup Scripts
  • Auto completion
  • Deployment workflow
  • Keymetrics monitoring
  • API

Answer 3

PM2 is a production process manager for Node.js 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. https://github.com/Unitech/pm2

Answer 4

If you are running OSX, then the easiest way to produce a true system process is to use launchd to launch it.

Build a plist like this, and put it into the /Library/LaunchDaemons with the name top-level-domain.your-domain.application.plist (you need to be root when placing it):

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
    <key>Label</key>
    <string>top-level-domain.your-domain.application</string>

    <key>WorkingDirectory</key>
    <string>/your/preferred/workingdirectory</string>

    <key>ProgramArguments</key>
    <array>
        <string>/usr/local/bin/node</string>
        <string>your-script-file</string>
    </array>

    <key>RunAtLoad</key>
    <true/>

    <key>KeepAlive</key>
    <true/>

</dict>
</plist>

When done, issue this (as root):

launchctl load /Library/LaunchDaemons/top-level-domain.your-domain.application.plist
launchctl start top-level-domain.your-domain.application

and you are running.

And you will still be running after a restart.

For other options in the plist look at the man page here: https://developer.apple.com/library/mac/documentation/Darwin/Reference/Manpages/man5/launchd.plist.5.html

Answer 5

I use tmux for a multiple window/pane development environment on remote hosts. It's really simple to detach and keep the process running in the background. Have a look at tmux

Answer 6

For people using newer versions of the daemon npm module - you need to pass file descriptors instead of strings:

var fs = require('fs');
var stdoutFd = fs.openSync('output.log', 'a');
var stderrFd = fs.openSync('errors.log', 'a');
require('daemon')({
    stdout: stdoutFd, 
    stderr: stderrFd
});