Using linger with Node.js

Overview

This article explains how to use linger with a Node.js application. This combination allows your app to run persistent processes and your services to restart if your app crashes or the server reboots.

You must be on a VPS or Dedicated hosting plan to install the software in these instructions.

Prerequisites

This article assumes you have set up a Proxy Server in the panel.

Step #1: Install linger

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

[server]$ loginctl enable-linger

This command will not respond with any output.

Step #2: Configure 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

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Article last updated PST.

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