Add new troubleshooting page - Collector not starting (#2255)

This PR adds a new troubleshooting topic that helps users resolve issues
where the EDOT Collector fails to start or crashes on launch.

Author: alexandra5000

troubleshoot/ingest/opentelemetry/edot-collector/collector-not-starting.md

@@ -0,0 +1,123 @@
+---
+navigation_title: Collector won't start
+description: Learn what to do when the EDOT Collector doesn’t start.
+applies_to:
+  stack:
+  serverless:
+    observability:
+  product:
+    edot_collector: ga
+products:
+  - id: cloud-serverless
+  - id: observability
+  - id: edot-collector
+---
+
+# EDOT Collector doesn’t start
+
+
+If your EDOT Collector fails to start, it's often due to configuration or environment-related issues. This guide walks you through the most common root causes and how to resolve them.
+
+## Symptoms   
+
+EDOT Collector fails to start or crashes immediately after launch.
+
+Possible causes include:
+
+* Invalid YAML configuration, including syntax errors or unsupported fields
+* Port binding conflicts, for example ports 4317 or 4318 already in use
+* Missing or misconfigured required components, such as `receivers` or `exporters`  
+* Incorrect permissions or volume mounts in containerized environments
+
+## Resolution
+
+The solution depends on your EDOT Collector's setup:
+
+* [Standalone](#standalone-edot-collector)
+* [Kubernetes](#kubernetes-edot-collector)
+
+### Standalone EDOT Collector
+
+If you're deploying the EDOT Collector in a standalone configuration, try to:
+
+* Validate configuration syntax
+
+   Run the following to validate your configuration without starting the Collector:
+
+   ```bash
+   otelcol validate --config=/path/to/otel-collector-config.yaml
+   ```
+   
+   This checks for syntax errors and missing components. 
+
+* Check logs for stack traces or component errors
+   
+   Review the Collector logs for error messages indicating configuration problems. Common examples include:
+
+   ```
+   error initializing exporter: no endpoint specified
+   ```
+   
+   Most critical issues, such as missing or invalid exporters or receivers, will be logged.
+   
+   To increase verbosity, run:
+   
+   ```bash
+   ./otelcol --set=service.telemetry.logs.level=debug
+   ```
+
+   This is especially helpful for diagnosing configuration parsing issues or startup errors.
+
+
+* Confirm required components are defined
+
+   Ensure `service.pipelines` references valid `receivers`, `processors`, and `exporters`. The minimal configuration depends on your use case:
+   
+   * **For logs**: `filelog` receiver, `resourcedetection` processor, `elasticsearch` exporter
+   
+   * **For traces**: `otlp` receiver, `elastictrace` and `elasticapm` processors, `elasticsearch` exporter
+   
+   * **For managed OTLP endpoint**: use relevant receivers and export using the `otlp` exporter
+   
+   Refer to [Default configuration of the EDOT Collector (Standalone)](opentelemetry://reference/edot-collector/config/default-config-standalone.md) for full examples for each use case.
+
+
+* Check for port conflicts
+
+   By default, EDOT uses:
+   
+   * 4317 for OTLP/gRPC
+   * 4318 for OTLP/HTTP
+   
+   Run this to check if a port is in use:
+
+   ```bash
+   lsof -i :4317
+   ```
+
+   If needed, adjust your configuration or free up the port.
+
+### Kubernetes EDOT Collector
+
+If you're deploying the EDOT Collector using the Elastic Helm charts, try to:
+
+* Double-check your custom `values.yaml` or -`-set` overrides for typos or missing fields.
+
+* Ensure volume mounts are correctly defined if you're using custom configuration files.
+
+* If you're managing the Collector through {{fleet}}, confirm that the policy includes a valid configuration and hasn't been corrupted or partially applied.
+
+* Use `kubectl logs <collector-pod>` to get Collector logs and diagnose startup failures.
+
+* Check the status of the pod using:
+
+    ```bash
+    kubectl describe pod <collector-pod>
+    ```
+
+  Common issues include volume mount errors, image pull failures, or misconfigured environment variables.
+
+## Resources
+
+* [Upstream Collector configuration documentation](https://opentelemetry.io/docs/collector/configuration/)  
+* [Elastic Stack Kubernetes Helm Charts](https://github.com/elastic/helm-charts)

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/collector-not-starting.md
   - file: edot-sdks/index.md
     children:
       - file: edot-sdks/android/index.md