Documentation Grafana Alloy Monitor metrics and logs Monitor syslog messages

Monitor RFC5424-compliant syslog messages with Grafana Alloy

RFC5424-compliant syslog messages follow a well-defined, standardized structure for logging. These logs include fields such as priority, timestamp, hostname, application name, process ID, message ID, structured data, and the actual message. With Alloy, you can collect your logs, forward them to a Grafana stack, and create dashboards to monitor your system behavior.

The alloy-scenarios repository contains complete examples of Alloy deployments. Clone the repository and use the examples to understand how Alloy collects, processes, and exports telemetry signals.

In this example scenario, Alloy listens for syslog messages over TCP or UDP connections and forwards them to a Loki destination.

Before you begin

Ensure you have the following:

• Docker
• Git

Clone and deploy the example

Follow these steps to clone the scenarios repository and deploy the monitoring example:

1. Clone the Alloy scenarios repository.

   shell Copy

   git clone https://github.com/grafana/alloy-scenarios.git

2. Start Docker to deploy the Grafana stack.

   shell Copy

   cd alloy-scenarios/syslog
   docker compose up -d

   Verify the status of the Docker containers:

   shell Copy

   docker ps

3. (Optional) Stop Docker to shut down the Grafana stack when you finish exploring this example.

   shell Copy

   docker compose down

Monitor and visualize your data

Use Grafana to monitor your deployment’s health and visualize your data.

Monitor Alloy

To monitor the health of your Alloy deployment, open your browser and go to http://localhost:12345.

For more information about the Alloy UI, refer to Debug Grafana Alloy.

Visualize your data

To use the Grafana Logs Drilldown, open your browser and go to http://localhost:3000/a/grafana-lokiexplore-app.

To create a dashboard to visualize metrics and logs, open your browser and go to http://localhost:3000/dashboards.

Understand the Alloy configuration

This example uses a config.alloy file to configure Alloy components for logging. You can find the config.alloy file in the cloned repository at alloy-scenarios/syslog/.

The configuration includes livedebugging to stream real-time data to the Alloy UI.

Configure livedebugging

Livedebugging streams real-time data from components directly to the Alloy UI. Refer to the Troubleshooting documentation for more details about this feature.

livedebugging

livedebugging is disabled by default. Enable it explicitly through the livedebugging configuration block to make debugging data visible in the Alloy UI.

alloy Copy

livedebugging {
  enabled = true
}

Configure logging

The logging configuration in this example requires two components:

• loki.source.syslog
• loki.write

loki.source.syslog

The loki.source.syslog component listens for syslog messages over TCP or UDP connections and forwards them to other Loki components. In this example, the component requires the following arguments:

• address: The host and port address to listen to for syslog messages.
• protocol: The protocol to listen to for syslog messages. The default is TCP.
• labels: The labels to associate with each received syslog record.
• forward_to: The list of receivers to send log entries to.

alloy Copy

loki.source.syslog "local" {
  listener {
    address  = "0.0.0.0:51893"
    labels   = { component = "loki.source.syslog", protocol = "tcp" }
  }

  listener {
    address  = "0.0.0.0:51898"
    protocol = "udp"
    labels   = { component = "loki.source.syslog", protocol = "udp" }
  }

  forward_to = [loki.write.local.receiver]
}

loki.write

The loki.write component writes logs to a Loki destination. In this example, the component requires the following arguments:

• url: Defines the full URL endpoint in Loki to send logs to.

alloy Copy

loki.write "local" {
  endpoint {
    url = "http://loki:3100/loki/api/v1/push"
  }
}