Add new troubleshooting page: Enable debug logging (for EDOT Collector) (#2230)

This PR introduces a new troubleshooting page that explains how to
enable debug-level logging for the EDOT Collector.

Closes [this
issue](elastic/opentelemetry#327).

---------

Co-authored-by: Fabrizio Ferri-Benedetti <[email protected]>
Co-authored-by: Brandon Morelli <[email protected]>

Author: 3 people

troubleshoot/ingest/opentelemetry/edot-collector/enable-debug-logging.md

@@ -0,0 +1,88 @@
+---
+navigation_title: Enable debug logging
+description: Learn how to enable debug logging for the EDOT Collector in supported environments.
+applies_to:
+  stack:
+  serverless:
+    observability:
+  product:
+    edot_collector: ga
+products:
+  - id: cloud-serverless
+  - id: observability
+  - id: edot-collector
+---
+
+# Enable debug logging
+
+You can enable debug-level logging in the Elastic Distributions of OpenTelemetry (EDOT) Collector by either modifying the configuration file or passing a runtime override. This is useful when troubleshooting startup issues or configuration problems.
+
+This guide shows how to enable debug logging in different environments.
+
+## Standalone EDOT Collector
+
+If you're running the EDOT Collector directly, you can choose between two approaches:
+
+* [Configuration file](#configuration-file) - to persist debug logging across restarts
+* [Temporary override: runtime flag](#temporary-override-runtime-flag) - for temporary debugging or quick tests
+
+Both approaches increase log verbosity and help surface misconfigurations.
+
+### Configuration file
+
+Add the following section to your EDOT Collector configuration file (typically `otel.yml`):
+
+```yaml
+service:
+  telemetry:
+    logs:
+      level: debug
+```
+
+This method works across all deployment environments.
+
+### Temporary override: runtime flag
+
+Pass the log level as a runtime argument using the `--set` flag:
+
+```bash
+otelcol --set=service.telemetry.logs.level=debug
+```
+
+This applies debug-level logging without modifying your configuration file.
+
+## Kubernetes (Helm deployment)
+
+If you're deploying the EDOT Collector using the OpenTelemetry Helm charts, enable debug logging by adding the configuration directly in your values.yaml file:
+
+```yaml
+config:
+  service:
+    telemetry:
+      logs:
+        level: debug
+```
+
+Alternatively, use a CLI override when installing or upgrading the [OpenTelemetry Collector Helm Chart](https://github.com/open-telemetry/opentelemetry-helm-charts/tree/main/charts/opentelemetry-collector) release:
+
+```bash
+helm upgrade my-opentelemetry-collector open-telemetry/opentelemetry-collector --set mode=daemonset --set image.repository="docker.elastic.co/elastic-agent/elastic-otel-collector" --set image.tag="9.1.0" --set config.service.telemetry.logs.level=debug
+```
+
+This ensures the Collector logs at debug level when deployed into your cluster.
+
+## Other environments
+
+Standalone and Kubernetes are currently the only officially supported deployment environments for the EDOT Collector.
+
+However, if you're running the Collector in a different context, such as a manually containerized setup, you can still enable debug logging using the same methods:
+
+* Add it to your configuration file using the `service.telemetry.logs.level` setting
+
+* Pass it at runtime with `--set=service.telemetry.logs.level=debug`
+
+:::{{note}}
+Debug logging for the Collector is not currently configurable through {{fleet}}.
+:::
+
+

troubleshoot/ingest/opentelemetry/toc.yml

@@ -6,6 +6,7 @@ toc:
     children:
       - file: edot-collector/collector-oomkilled.md
       - file: edot-collector/metadata.md
+      - file: edot-collector/enable-debug-logging.md
       - file: edot-collector/collector-not-starting.md
   - file: edot-sdks/index.md
     children: