Add documentation page for the EDOT Collector APM config connector (#11344) (#11461)

* Add apmconfigextension docs

* Update for clarity and detail

* Alphabetize components in toc

* Apply comments

(cherry picked from commit 0d53bef)

Co-authored-by: Aleksandra Spilkowska <[email protected]>

Author: mergify[bot]

docs/reference/edot-collector/components/apmconfigextension.md

@@ -0,0 +1,113 @@
+---
+navigation_title: APM Config extension
+description: The APM Config extension is an OpenTelemetry Collector component that enables central configuration delivery for EDOT SDKs using the Open Agent Management Protocol (OpAMP).
+applies_to:
+  stack:
+  serverless:
+  observability:
+  product:
+    edot_collector:
+products:
+  - id: elastic-agent
+  - id: observability
+  - id: edot-collector
+---
+
+# APM Config extension
+
+The {{product.apm}} Config extension (`apmconfigextension`) enables central configuration for {{edot}} SDKs through the Open Agent Management Protocol (OpAMP). It establishes a control channel between the {{edot}} Collector and an OpAMP-enabled {{product.apm-server}} endpoint so that configuration updates can be retrieved and delivered dynamically to connected SDKs.
+
+{applies_to}`stack: ga 9.1` This extension is required when using the [Central Configuration feature](docs-content://solutions/observability/apm/opentelemetry/edot-sdks-central-configuration.md) for {{edot}} SDKs.
+
+For full contrib details, refer to the [OpenTelemetry `apmconfigextension` documentation](https://github.com/elastic/opentelemetry-collector-components/tree/main/extension/apmconfigextension).
+
+## How it works
+
+The extension acts as an OpAMP client, opening a bidirectional control channel to the OpAMP endpoint exposed by {{product.apm-server}}. Through this channel:
+
+1. The Collector requests configuration bundles for connected {{edot}} SDKs.
+2. The configuration server sends updates based on user changes in the Applications UI.
+3. Updated configuration is distributed to {{edot}} SDKs using OpAMP-supported mechanisms.
+
+The extension does not modify telemetry or manage pipelines. Its sole purpose is configuration synchronization.
+
+## Typical use cases
+
+Common scenarios where the {{product.apm}} Config extension is required:
+
+* Central configuration for {{edot}} SDKs. Enables dynamic updates to sampling, attribute collection, security settings, and custom SDK options.
+
+* Standalone {{edot}} Collector deployments. The extension can connect directly to the {{product.apm-server}} OpAMP endpoint.
+
+* Managing large fleets of instrumented services. Allows consistent and centralized control of SDK configuration without requiring application restarts.
+
+:::{note}
+Integration with {{fleet}} Server (Fleet OpAMP endpoint) is not available at this time.
+:::
+
+## Example configuration
+
+The following examples show how to configure the {{product.apm}} Config extension for different deployment scenarios:
+
+### Standalone {{edot}} Collector
+
+```yaml
+extensions:
+  bearertokenauth:
+    scheme: "APIKey"
+    token: "<ENCODED_ELASTICSEARCH_APIKEY>"
+
+  apmconfig:
+    opamp:
+      protocols:
+        http:
+          endpoint: "https://apm.example.com:8200/opamp"
+          
+    source:
+      elasticsearch:
+        endpoint: "<ELASTICSEARCH_ENDPOINT>"
+        auth:
+          authenticator: bearertokenauth
+
+service:
+  extensions: [bearertokenauth, apmconfig]
+```
+
+### Custom OpAMP settings
+
+You can configure timeouts or connection behavior:
+
+```yaml
+extensions:
+  apmconfig:
+    opamp:
+      protocols:
+        http:
+          endpoint: "https://apm.example.com:8200/opamp"
+          timeout: 30s
+          tls:
+            insecure_skip_verify: false
+```
+
+## Key configuration options
+
+The following are the most important settings when configuring the {{product.apm}} Config extension:
+
+| Option | Description |
+|--------|-------------|
+| `opamp.protocols.http.endpoint` | The OpAMP server endpoint. Required for standalone deployments. |
+| `opamp.protocols.http.headers` | HTTP headers used for authentication, such as API keys. |
+| `opamp.protocols.http.tls` | TLS options, including certificate verification behavior. |
+| `opamp.protocols.http.timeout` | Timeout for OpAMP communication. |
+
+:::{note}
+The endpoint must point to an OpAMP-enabled {{product.apm-server}} Server. Standard ingest or OTLP endpoints will not work.
+:::
+
+For the complete list of configuration options, refer to the [contrib `apmconfigextension` documentation](https://github.com/elastic/opentelemetry-collector-components/tree/main/extension/apmconfigextension).
+
+## Resources
+
+* [Contrib component: apmconfigextension](https://github.com/elastic/opentelemetry-collector-components/tree/main/extension/apmconfigextension)
+* [OpAMP specification](https://opentelemetry.io/docs/specs/opamp/)
+* [Central configuration for {{edot}} SDKs](docs-content://solutions/observability/apm/apm-agent-central-configuration.md)

docs/reference/edot-collector/toc.yml

@@ -14,22 +14,16 @@ toc:
       - file: config/proxy.md
   - file: components.md
     children:
-<<<<<<< HEAD
-=======
       - file: components/apmconfigextension.md
       - file: components/attributesprocessor.md
       - file: components/elasticapmconnector.md
       - file: components/elasticapmintakereceiver.md
       - file: components/elasticapmprocessor.md
->>>>>>> 4d7a357d7 (Add documentation page for the EDOT Collector attributes processor (#11331))
       - file: components/elasticsearchexporter.md
-      - file: components/elasticapmintakereceiver.md
-      - file: components/k8sclusterreceiver.md
-      - file: components/elasticapmprocessor.md
-      - file: components/elasticapmconnector.md
       - file: components/filelogreceiver.md
-      - file: components/k8sobjectsreceiver.md
       - file: components/hostmetricsreceiver.md
+      - file: components/k8sclusterreceiver.md
+      - file: components/k8sobjectsreceiver.md
       - file: components/kubeletstatsreceiver.md
   - file: customization.md
     children: