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Configuring a Cluster Diagnostic Instance

The cluster diagnostic instance is an optional, but strongly recommended, aid to monitoring the health and performance of the Seq cluster. Seq nodes in the cluster send OpenTelemetry logs, metrics, and traces to the diagnostic instance for:

  • Query tracing, including full visualizations of how a Seq query handled by the cluster was distributed over the participating nodes,
  • Error monitoring and problem troubleshooting, and
  • Visualization of key performance and health metrics.

These instructions show how to configure an additional Seq server for use as the diagnostic instance, however, any standard OTLP receiver can be used. Contact the Seq support team for advice if you are configuring an alternative monitoring tool for use as a cluster diagnostic instance.

Provisioning the Diagnostic Instance

First, provision an additional Seq instance using the instructions in Getting Started.

Cluster Worksheet Update

Assuming your diagnostic instance listens on port 80, the Diagnostic Instance Ingestion URI will be an HTTP URL pointing at the diagnostic instance, with /ingest/otlp appended. For example, http://diagnostics.seq.local/ingest/otlp. Don't forget to add that path to the URL.

The diagnostic instance must be accessible to the cluster nodes at the Diagnostic Instance Ingestion URI.

Retention Policy Configuration

The diagnostic instance does not need a long retention window. Setting a limited retention window will reduce the likelihood of disk space exhaustion and similar issues.

Because only low-volume information is sent from the cluster, a good starting point is to set a 30 day "all events" retention policy on the diagnostic instance.

In Data > Storage, choose Add Retention Policy:

API Key Creation

Cluster nodes should authenticate with the diagnostic instance when sending data.

First, in Settings > API Keys, choose "Require an API key for HTTP/S ingestion":

Then, choose Add API Key and create a new key with Ingestion permissions:

The screen after saving the new API key: the generated API key token is shown ready to copy.


Cluster Worksheet Update

Add the generated Diagnostic Instance API Key token to the cluster worksheet.