### Understand the alert

This alert is triggered when a `systemd path unit` enters a `failed state`. Service units in a failed state indicate an issue with the service's startup, runtime, or shutdown, which can result in the service being marked as failed.

### What is a systemd path unit?

`systemd` is an init system and system manager that manages services and their dependencies on Linux systems. A `path unit` is a type of unit configuration file that runs a service in response to the existence or modification of files and directories. These units are used to monitor files and directories and trigger actions based on changes to them.

### Troubleshoot the alert

1. Identify the failed systemd path unit

First, you need to identify which path unit is experiencing issues. To list all failed units:

   ```
   systemctl --state=failed
   ```

Take note of the units indicated as 'path' in the output.

2. Inspect the path unit status

To get more details about the specific failed path unit, run:

   ```
   systemctl status <failed-path-unit>
   ```

Replace `<failed-path-unit>` with the name of the failed path unit you identified previously.

3. Review logs for the failed path unit

To view the logs for the failed path unit, use the `journalctl` command:

   ```
   journalctl -u <failed-path-unit>
   ```

Again, replace `<failed-path-unit>` with the name of the failed path unit. Review the logs to identify possible reasons for the failure.

4. Reload the unit configuration (if necessary)

If you discovered an issue in the unit configuration file and resolved it, reload the configuration by running:

   ```
   sudo systemctl daemon-reload
   ```

5. Restart the failed path unit

Once you have identified and resolved the issue causing the failed state, try to restart the path unit:

   ```
   sudo systemctl restart <failed-path-unit>
   ```

Replace `<failed-path-unit>` with the name of the failed path unit. Then, monitor the path unit status to ensure it is running without issues.

### Useful resources

1. [Introduction to Systemd Units and Unit Files](https://www.digitalocean.com/community/tutorials/understanding-systemd-units-and-unit-files)
