Add OTLP docs

manage-data/data-store/data-streams/quickstart-tsds.md

@@ -315,9 +315,10 @@ This quickstart introduced the basics of time series data streams. To learn more
 
 * [](/manage-data/data-store/data-streams/time-series-data-stream-tsds.md)
 * [](/manage-data/data-store/data-streams/set-up-tsds.md)
+* [](/manage-data/data-store/data-streams/tsds-ingest-otlp.md)
 
 For more information about the APIs used in this quickstart, review the {{es}} API reference documentation:
 
 * [Bulk API](https://www.elastic.co/docs/api/doc/elasticsearch/operation/operation-bulk)
 * [Index template API](https://www.elastic.co/docs/api/doc/elasticsearch/operation/operation-indices-put-index-template)
-* [Search API](https://www.elastic.co/docs/api/doc/elasticsearch/operation/operation-search)
+* [Search API](https://www.elastic.co/docs/api/doc/elasticsearch/operation/operation-search)

manage-data/data-store/data-streams/set-up-tsds.md

@@ -11,7 +11,10 @@ products:
 
 # Set up a time series data stream [set-up-tsds]
 
-This page shows you how to set up a [time series data stream](/manage-data/data-store/data-streams/time-series-data-stream-tsds.md) (TSDS).
+This page shows you how to manually set up a [time series data stream](/manage-data/data-store/data-streams/time-series-data-stream-tsds.md) (TSDS).
+
+For a simplified setup that doesn't require manually mapping dimension and metric fields via index templates,
+have a look at the [OpenTelemetry Protocol (OTLP)-based data ingestion](tsds-ingest-otlp.md).
 
 ## Before you begin [tsds-prereqs]
 
@@ -188,4 +191,4 @@ Now that you've set up a time series data stream, you can manage and use it like
 * [Use a data stream](use-data-stream.md) for indexing and searching
 * [Change data stream settings](modify-data-stream.md#data-streams-change-mappings-and-settings) as needed
 * Query time series data using the {{esql}} [`TS` command](elasticsearch://reference/query-languages/esql/commands/ts.md)
-* Use [data stream APIs](https://www.elastic.co/docs/api/doc/elasticsearch/group/endpoint-data-stream)
+* Use [data stream APIs](https://www.elastic.co/docs/api/doc/elasticsearch/group/endpoint-data-stream)

manage-data/data-store/data-streams/time-series-data-stream-tsds.md

@@ -117,6 +117,7 @@ You can use the {{esql}} [`TS` command](elasticsearch://reference/query-language
 
 * Try the [quickstart](/manage-data/data-store/data-streams/quickstart-tsds.md) for a hands-on introduction
 * [Set up a time series data stream](/manage-data/data-store/data-streams/set-up-tsds.md)
+* [Ingest data via the OpenTelemetry Protocol (OTLP)](/manage-data/data-store/data-streams/tsds-ingest-otlp.md)
 * Learn about [downsampling](/manage-data/data-store/data-streams/downsampling-time-series-data-stream.md) to reduce storage footprint
 
 % suppress anchor warnings until chicken-and-egg resolved
@@ -125,4 +126,4 @@ You can use the {{esql}} [`TS` command](elasticsearch://reference/query-language
 ##### [tsds-look-back-time]
 ##### [time-bound-indices]
 ##### [dimension-based-routing]
-##### [tsds-accepted-time-range]
+##### [tsds-accepted-time-range]

manage-data/data-store/data-streams/tsds-ingest-otlp.md

@@ -0,0 +1,98 @@
+---
+navigation_title: "Ingest OTLP metrics"
+applies_to:
+  stack: preview 9.2
+  serverless: preview
+products:
+  - id: elasticsearch
+---
+
+# Ingest metrics via the OpenTelemetry Protocol (OTLP)
+
+In addition to the ingestion of metrics data via the bulk API,
+{{es}} offers an alternative way to ingest data via the [OpenTelemetry Protocol (OTLP)](https://opentelemetry.io/docs/specs/otlp).
+
+The endpoint is available under `/_otlp/v1/metrics`.
+
+Ingesting metrics data via this endpoint has the following advantages:
+* Improved ingestion performance, especially if the data contains many resource attributes.
+* Simplified index mapping:
+  there's no need to manually create an index template, or define dimensions and metrics.
+  Using the OTLP endpoint, metrics are dynamically mapped using the metadata included in the OTLP requests.
+
+## How to send data to the OTLP endpoint
+
+To send data from an OpenTelemetry collector to the {{es}} OTLP endpoint,
+use the [`OTLP/HTTP` exporter](https://github.com/open-telemetry/opentelemetry-collector/tree/main/exporter/otlphttpexporter).
+This is an example configuration:
+
+```yaml
+extensions:
+  basicauth/elasticsearch:
+    client_auth:
+      username: <user>
+      password: <password>
+exporters:
+  otlphttp/elasticsearch:
+    endpoint: <es_endpoint>/_otlp
+    sending_queue:
+      enabled: true
+      sizer: requests
+      queue_size: 5000
+      block_on_overflow: true
+      batch:
+        flush_timeout: 5s
+        sizer: bytes
+        min_size: 2_000_000
+        max_size: 5_000_000
+    auth:
+      authenticator: basicauth/elasticsearch
+```
+Note that at this point, only `encoding: proto` is supported,
+which the `OTLP/HTTP` exporter uses by default.
+
+The supported options for `compression` are `gzip` (default value of the `OTLP/HTTP` exporter) and `none`.
+
+[//]: # (TODO we might actually also support snappy and zstd, test and update accordingly)
+
+To track metrics in your custom application,
+use the [OpenTelemetry language SDK](https://opentelemetry.io/docs/getting-started/dev/) of your choice.
+
+## When not to use the {{es}} OTLP endpoint
+
+On Elastic Cloud, use the [Elastic Cloud Managed OTLP Endpoint](opentelemetry:/reference/motlp.md) instead of connecting directly to the Elasticsearch OTLP endpoint.
+
+It's not recommended to send metrics from applications directly to the Elasticsearch OTLP endpoint,
+especially if there are many individual applications that each periodically send a small amount of metrics.
+Instead, send data to an OpenTelemetry collector first.
+This helps with handling many connections,
+and with creating bigger batches to improve ingestion performance.
+For more details on the recommended way to set up OpenTelemetry-based data ingestion,
+have a look at the [EDOT reference architecture](opentelemetry:/reference/architecture/index.md).
+
+At this point, {{es}} only supports the OTLP metrics endpoint (`/_otlp/v1/metrics`).
+Other signals,  are not supported as a native {{es}} OTLP endpoint at the moment.
+To ingest other signals,
+such as logs, traces, and profiles,
+use a distribution of the OpenTelemetry collector that includes the [Elasticsearch exporter](opentelemetry:/reference/edot-collector/components/elasticsearchexporter.md),
+such as the [Elastic distribution of OpenTelemetry (EDOT) Collector](opentelemetry:/reference/edot-collector/index.md).
+
+## Send data to different data streams
+
+By default, metrics are ingested into the `metrics-generic.otel-default` data stream.
+You can influence the target data stream by setting specific attributes on your data:
+
+- `data_stream.dataset` or `data_stream.namespace` in attributes, with the following order of precedence: data point attribute -> scope attribute -> resource attribute
+- Otherwise, if the scope name contains `/receiver/<somereceiver>`, `data_stream.dataset` is set to the receiver name.
+- Otherwise, `data_stream.dataset` falls back to `generic` and `data_stream.namespace` falls back to `default`.
+
+The target data stream name is constructed as `metrics-${data_stream.dataset}.otel-${data_stream.namespace}`.
+
+## Mapping hints
+
+## Limitations
+
+* Histograms are only supported in delta temporality.
+  Set the temporality preference to delta in your SDKs,
+  or use the [`cumulativetodelta` processor](https://github.com/open-telemetry/opentelemetry-collector-contrib/tree/main/processor/cumulativetodeltaprocessor) to avoid cumulative histograms to be dropped.
+* Exemplars are not supported.

manage-data/toc.yml

@@ -15,14 +15,15 @@ toc:
             children:
               - file: data-store/data-streams/quickstart-tsds.md
               - file: data-store/data-streams/set-up-tsds.md
+              - file: data-store/data-streams/tsds-ingest-otlp.md
               - file: data-store/data-streams/downsampling-time-series-data-stream.md
                 children:
                 - file: data-store/data-streams/downsampling-concepts.md
                 - file: data-store/data-streams/run-downsampling.md
                 - file: data-store/data-streams/query-downsampled-data.md
               - file: data-store/data-streams/advanced-topics-tsds.md
-                children:              
-                - file: data-store/data-streams/time-bound-tsds.md              
+                children:
+                - file: data-store/data-streams/time-bound-tsds.md
                 - file: data-store/data-streams/reindex-tsds.md
           - file: data-store/data-streams/logs-data-stream.md
           - file: data-store/data-streams/failure-store.md
@@ -167,4 +168,4 @@ toc:
       - file: migrate/migrate-from-a-self-managed-cluster-with-a-self-signed-certificate-using-remote-reindex.md
       - file: migrate/migrate-internal-indices.md
       - file: migrate/migrate-data-between-elasticsearch-clusters-with-minimal-downtime.md
-  - file: use-case-use-elasticsearch-to-manage-time-series-data.md
+  - file: use-case-use-elasticsearch-to-manage-time-series-data.md