Using linger with Node.js

Overview

linger lets a Node.js application run persistent processes, automatically restarting your services if the app crashes or the server reboots.

Step 1 — Installing linger

To install linger under your user, log in to your server via SSH and run the following command:

[server]$ loginctl enable-linger

Step 2 — Configuring systemd user unit

This step configures Node to work with systemd user units on the server.

1. Create the following directories:

   [server]$ mkdir -p ~/.config/systemd/user/

2. Create a myapp.service file in the .config/systemd/user directory:

   [server]$ nano ~/.config/systemd/user/myapp.service

3. Add the following code to this file:

   [Unit]
   Description=Systemd instance to serve Node application
   After=network.target
   
   [Service]
   WorkingDirectory=/path/to/your/app
   ExecStart=/usr/bin/node /path/to/your/app/app.js
   Environment="PATH=/usr/bin:/usr/local/bin"
   Environment=NODE_ENV=production
   ExecReload=/bin/kill -s HUP $MAINPID
   KillMode=mixed
   TimeoutStopSec=5
   PrivateTmp=true
   Restart=on-failure
   
   [Install]
   WantedBy=default.target
   

4. Edit the highlighted lines above as follows:

   • WorkingDirectory: The path to your website application.

   • ExecStart: The path to your node installation.

5. Enable the user unit for your Node app:

   [server]$ systemctl --user enable myapp
   

6. Start the user unit for your Node app:

   [server]$ systemctl --user start myapp
   

7. Confirm it is running:

   [server]$ systemctl --user status myapp
   

Your app's services will now automatically restart when the server reboots or if the application crashes.

See also

• Proxy Server

• SSH overview

• Installing a custom version of NVM and Node.js