Scribbles for my bad memory

TL;DR

If your user-level systemd service on Ubuntu doesn't start automatically after a reboot, enable it with systemctl --user enable HappyNotes.Api.service. If you encounter an error about an existing symlink, remove it first. To allow the service to run without an active user session, enable lingering using loginctl enable-linger <username>. Finally, ensure your service file has the correct [Install] section and reboot to check if the service starts as expected.

The Problem

After configuring a user-level service with systemd, you might find that it remains inactive after rebooting your server. For example, you may run the command:

systemctl --user status HappyNotes.Api.service

And see output indicating that the service is inactive (dead) and disabled.

Solution Steps

1. Enable the Service: First, ensure your service is enabled to start at boot:

   systemctl --user enable HappyNotes.Api.service
   

   If you encounter an error stating that the service is already linked, you may need to remove the existing symlink:

   rm ~/.config/systemd/user/default.target.wants/HappyNotes.Api.service
   

2. Check for Linger: User-level services require an active user session to run. To allow your user services to run even when you're not logged in, enable lingering:

   loginctl enable-linger $USER
   

3. Verify Service Configuration: Ensure your service file has the correct [Install] section:

   [Install]
   WantedBy=default.target
   

4. Reboot and Test: After enabling lingering and ensuring your service is set up correctly, reboot your server:

   sudo reboot
   

   After rebooting, check the status of your service again:

   systemctl --user status HappyNotes.Api.service
   

By following these steps, you can ensure that your user-level systemd services start automatically after a reboot on Ubuntu. Enabling lingering is the key, which is particularly useful for server environments where continuous operation of services is desired.

In short:

Change the service file, and add two lines after [Service] line,

[Service]
LimitNOFILE=65535
LimitNOFILESoft=65535

If you want to know more, read the Reference