The easiest tool to use for piping a log file from journald to Grafana would probably be Loki. Loki was developed by the Grafana team specifically for the purpose of log aggregation, and it's designed to work seamlessly with Grafana for visualization. Therefore, the integration between Loki and Grafana is likely to be smoother and require fewer steps than the other two options.

Setting up Loki and getting it to work with journald and Grafana involves the following steps:

1. Installing Loki: You can download precompiled binaries directly from the Loki GitHub page or use Docker to run Loki. The Docker approach is usually easier, as you only need to pull the image and start a container.

2. Configuring Loki: This involves creating a config file that Loki will use to know where and how to store the logs. You can find example configuration files in the Loki repository to guide you.

3. Installing Promtail: Promtail is the agent that ships the logs from your servers to Loki. Promtail can read logs from many different places, including journald. Like Loki, you can install Promtail by downloading a precompiled binary or using Docker.

4. Configuring Promtail: The main thing you'll need to configure is the scrape_configs section of the Promtail config file. This is where you tell Promtail where to find the logs it should be shipping. For journald logs, you can use the journal block. You'll also need to set the loki_push_url to the URL of your Loki server.

5. Connecting Loki to Grafana: Finally, you'll need to add Loki as a data source in Grafana. This is done in the Grafana UI and simply involves providing the URL of your Loki server.

Remember to check official documentation for the most recent and detailed steps, as these can change with new releases and updates.