troubleshoot(otel): add generic.otel index template troubleshooting page (#6974)

troubleshoot/ingest/opentelemetry/edot-collector/index.md

@@ -29,6 +29,8 @@ If you're not sure where to start, review the Collector's logs for error message
 
 * [Missing or incomplete traces due to Collector sampling](/troubleshoot/ingest/opentelemetry/edot-collector/misconfigured-sampling-collector.md): Troubleshoot missing or incomplete traces caused by sampling configuration.
 
+* [{{es}} `generic.otel` index template missing or misconfigured](/troubleshoot/ingest/opentelemetry/edot-collector/missing-otel-index-template.md): Resolve silent ingest failure caused by a missing or misconfigured `generic.otel` index template when using `mapping.mode: otel`.
+
 * [Collector doesn't propagate client metadata](/troubleshoot/ingest/opentelemetry/edot-collector/metadata.md): Learn why the Collector doesn't extract custom attributes and how to propagate such values using EDOT SDKs.
 
 ## Connectivity and export issues

troubleshoot/ingest/opentelemetry/edot-collector/missing-otel-index-template.md

@@ -0,0 +1,90 @@
+---
+navigation_title: generic.otel template missing
+description: Troubleshoot silent ingest failure when the `generic.otel` index template is missing or misconfigured in Elasticsearch.
+applies_to:
+  stack: ga
+  serverless:
+    observability: ga
+  product:
+    edot_collector: ga
+products:
+  - id: cloud-serverless
+  - id: observability
+  - id: edot-collector
+---
+
+# {{es}} `generic.otel` index template missing or misconfigured [missing-otel-index-template]
+
+When using the `elasticsearch` exporter with `mapping.mode: otel`, telemetry is written to the `generic.otel` data streams. If the backing index template is absent or misconfigured, ingest silently fails, which means that the Collector pipeline reports success, but no data appears in {{kib}}.
+
+## Symptoms
+
+* The Collector reports successful telemetry export with no errors in logs
+* No data appears in {{kib}} {{product.apm}} or Discover
+* The `logs-generic.otel-*`, `metrics-generic.otel-*`, or `traces-generic.otel-*` data streams are empty or absent
+* {{es}} returns mapping errors on direct data stream queries
+
+## Causes
+
+<!-- TODO: SME confirmation needed — who installs the generic.otel templates (EDOT Collector on first run? {{fleet}}? ES itself?) and what triggers reinstallation? -->
+* The template is not installed yet. On a fresh {{es}} installation where EDOT has not yet run successfully, the `generic.otel` templates might be missing.
+* If the `elasticsearch` exporter is configured without `mapping.mode: otel`, data is written to the default {{es}} templates instead of the `generic.otel` ones. This can cause mapping conflicts or route data to unexpected indices.
+
+## Resolution
+
+::::{stepper}
+
+:::{step} Verify the index template is installed
+
+Run the following queries in {{kib}} **Dev Tools** or in the {{es}} API:
+
+```bash
+GET _index_template/logs-generic.otel
+GET _component_template/generic.otel@mappings
+```
+
+If either one returns a 404, it means that the template is missing. Continue to [Reinstall the index template](#reinstall-the-index-template).
+
+If both return results, the template is present. You can skip to [Verify `mapping.mode: otel` is set on the exporter](#verify-mappingmode-otel-is-set-on-the-exporter).
+:::
+
+:::{step} Reinstall the index template
+
+<!-- TODO: SME confirmation needed — what are the exact steps to reinstall or repair the generic.otel template? Is it a Collector restart, a Fleet policy push, or a manual ES API call? -->
+
+Restart the EDOT Collector to trigger template bootstrapping. If the Collector connects to {{es}} successfully on startup, it installs the required templates automatically.
+
+If the template is still missing after a restart, contact [Elastic Support](https://www.elastic.co/support) to get help with manual template installation.
+:::
+
+:::{step} Verify `mapping.mode: otel` is set on the exporter
+
+Check your Collector configuration and confirm the `elasticsearch` exporter includes `mapping.mode: otel`:
+
+```yaml
+exporters:
+  elasticsearch/otel:
+    endpoints:
+      - ${env:ELASTIC_ENDPOINT}
+    api_key: ${env:ELASTIC_API_KEY}
+    mapping:
+      mode: otel
+```
+
+Without this setting, the exporter writes to the default {{es}} templates, bypassing `generic.otel` entirely. Data might appear in unexpected indices or fail silently due to mapping conflicts.
+:::
+
+:::{step} Confirm data is flowing
+
+After verifying the template and exporter configuration, check for incoming data:
+
+```bash
+GET logs-generic.otel-default/_count
+GET metrics-generic.otel-default/_count
+GET traces-generic.otel-default/_count
+```
+
+A non-zero count confirms that data is reaching {{es}}. If counts remain zero, refer to [No logs, metrics, or traces visible in {{kib}}](/troubleshoot/ingest/opentelemetry/no-data-in-kibana.md) for further diagnostics.
+:::
+
+::::

troubleshoot/ingest/opentelemetry/no-data-in-kibana.md

@@ -37,6 +37,7 @@ This issue is typically caused by one or more of the following:
 * Network issues, such as proxy misconfigurations
 * TLS verification failures
 * Misconfigured pipelines or disabled signals
+* Missing or misconfigured `generic.otel` index template — when using `mapping.mode: otel`, if the template hasn't been installed yet or the exporter is misconfigured, the Collector reports success but no data reaches {{kib}}. Refer to [{{es}} `generic.otel` index template missing or misconfigured](/troubleshoot/ingest/opentelemetry/edot-collector/missing-otel-index-template.md) for more information.
 * Incomplete setup — to capture all telemetry data, you must use the EDOT Collector together with an appropriate EDOT SDK
 
 ## Resolution

troubleshoot/toc.yml

@@ -154,6 +154,7 @@ toc:
               - file: ingest/opentelemetry/edot-collector/enable-debug-logging.md
               - file: ingest/opentelemetry/edot-collector/collector-not-starting.md
               - file: ingest/opentelemetry/edot-collector/misconfigured-sampling-collector.md
+              - file: ingest/opentelemetry/edot-collector/missing-otel-index-template.md
               - file: ingest/opentelemetry/edot-collector/trace-export-errors.md
               - file: ingest/opentelemetry/edot-collector/c2c-resourceexhausted.md
           - file: ingest/opentelemetry/edot-sdks/index.md