Running a Node.js application using nvm as a systemd service

.md

Read this first!

Hi there! Since this post was originally written, nvm has gained some new tools, and some people have suggested alternative (and potentially better) approaches for modern systems. Make sure to have a look at the comments to this article, before following this guide!

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The original article

Trickier than it seems.

1. Set up nvm

Let's assume that you've already created an unprivileged user named myapp. You should never run your Node.js applications as root!

Switch to the myapp user, and do the following:

1. curl -o- https://raw.githubusercontent.com/creationix/nvm/v0.31.0/install.sh | bash (however, this will immediately run the nvm installer - you probably want to just download the install.sh manually, and inspect it before running it)
2. Install the latest stable Node.js version: nvm install stable

2. Prepare your application

Your package.json must specify a start script, that describes what to execute for your application. For example:

...
"scripts": {
    "start": "node app.js"
},
...

3. Service file

Save this as /etc/systemd/system/my-application.service:

[Unit]
Description=My Application

[Service]
EnvironmentFile=-/etc/default/my-application
ExecStart=/home/myapp/start.sh
WorkingDirectory=/home/myapp/my-application-directory
LimitNOFILE=4096
IgnoreSIGPIPE=false
KillMode=process
User=myapp

[Install]
WantedBy=multi-user.target

You'll want to change the User, Description and ExecStart/WorkingDirectory paths to reflect your application setup.

4. Startup script

Next, save this as /home/myapp/start.sh (adjusting the username in both the path and the script if necessary):

#!/bin/bash
. /home/myapp/.nvm/nvm.sh
npm start

This script is necessary, because we can't load nvm via the service file directly.

Make sure to make it executable:

chmod +x /home/myapp/start.sh

5. Enable and start your service

Replace my-application with whatever you've named your service file after, running the following as root:

1. systemctl enable my-application
2. systemctl start my-application

To verify whether your application started successfully (don't forget to npm install your dependencies!), run:

systemctl status my-application

... which will show you the last few lines of its output, whether it's currently running, and any errors that might have occurred.

Done!

This is what works for both starting and stopping.

[Service]
Environment=NODE_VERSION=17.3.0 NODE_ENV=production
WorkingDirectory=/root/project
ExecStart=/root/.nvm/nvm-exec /root/project/index.js
...

nvm-exec is the right answer, thanks to point it out

For the nvm-exec method, in my case the Environment=NODE_VERSION... arguments did not work, and I received the following error:
No NODE_VERSION provided; no .nvmrc file found
I had to include a .nvmrc file in the project WorkingDirectory. The .nvmrc file is a text file that simply contains the version number that you want to run as such as "10.20.0".