[CONTP-1096] Document check_tag_cardinality in Kubernetes Autodiscovery annotations

content/en/containers/kubernetes/integrations.md

@@ -371,6 +371,35 @@ The `ad_identifiers` parameter takes a list, so you can supply multiple containe
 `<LOGS_CONFIG>`
 : The configuration parameters listed under `logs` in your integration's `<INTEGRATION_NAME>.d/conf.yaml.example` file.
 
+### Advanced annotation parameters
+
+In addition to the core Autodiscovery annotations for checks, logs, and instances, you can use additional annotations to customize check behavior:
+
+#### Tag cardinality
+
+Set the tag cardinality level for a specific check using the `check_tag_cardinality` annotation. This overrides the global Agent tag cardinality setting for metrics collected by that check.
+
+```yaml
+apiVersion: v1
+kind: Pod
+metadata:
+  name: '<POD_NAME>'
+  annotations:
+    ad.datadoghq.com/<CONTAINER_NAME>.checks: |
+      {
+        "<INTEGRATION_NAME>": {
+          "init_config": <INIT_CONFIG>,
+          "instances": [<INSTANCES_CONFIG>]
+        }
+      }
+    ad.datadoghq.com/<CONTAINER_NAME>.check_tag_cardinality: "<low|orchestrator|high>"
+spec:
+  containers:
+    - name: '<CONTAINER_NAME>'
+```
+
+For more information about tag cardinality, see [Per-check tag configuration][27].
+
 ### Auto-configuration
 
 The Datadog Agent automatically recognizes and supplies basic configuration for some common technologies. For a complete list, see [Autodiscovery auto-configuration][20].
@@ -673,3 +702,4 @@ For more examples, including how to configure multiple checks for multiple sets
 [24]: /containers/guide/autodiscovery-examples
 [25]: /integrations/istio/
 [26]: /integrations/postgres
+[27]: /getting_started/integrations/#per-check-tag-configuration

content/en/getting_started/integrations/_index.md

@@ -108,13 +108,16 @@ To better unify your environment, it is also recommended to configure the `env`
 You can customize tag behavior for individual checks, overriding the global Agent-level settings:
 
 1. **Disable Autodiscovery tags**
-    
+
     By default, the metrics reported by integrations include tags automatically detected from the environment. For example, the metrics reported by a Redis check that runs inside a container include tags associated with the container, such as `image_name`. You can turn this behavior off by setting the `ignore_autodiscovery_tags` parameter to `true`.
 
 1. **Set tag cardinality per integration check**
-    
+
     You can define the level of tag cardinality (low, orchestrator, or high) on a per-check basis using the `check_tag_cardinality` parameter. This overrides the global tag cardinality setting defined in the Agent configuration.
 
+{{< tabs >}}
+{{% tab "Configuration file" %}}
+
 ```yaml
 init_config:
 # Ignores tags coming from autodiscovery
@@ -126,6 +129,50 @@ check_tag_cardinality: low
 # Rest of the config here
 ```
 
+{{% /tab %}}
+{{% tab "Kubernetes annotations" %}}
+
+For containerized environments using Kubernetes, you can set these parameters through [Autodiscovery annotations][1]:
+
+```yaml
+apiVersion: v1
+kind: Pod
+metadata:
+  name: redis-app
+  annotations:
+    ad.datadoghq.com/redis.checks: |
+      {
+        "redisdb": {
+          "init_config": {},
+          "instances": [
+            {
+              "host": "%%host%%",
+              "port": 6379
+            }
+          ]
+        }
+      }
+    ad.datadoghq.com/redis.check_tag_cardinality: "low"
+spec:
+  containers:
+    - name: redis
+      image: redis:latest
+```
+
+The supported annotation format is:
+```
+ad.datadoghq.com/<CONTAINER_NAME>.check_tag_cardinality: "<CARDINALITY_LEVEL>"
+```
+
+Where `<CARDINALITY_LEVEL>` can be `low`, `orchestrator`, or `high`.
+
+[1]: /containers/kubernetes/integrations/?tab=annotations#configuration
+
+{{% /tab %}}
+{{< /tabs >}}
+
+<div class="alert alert-info">The <code>check_tag_cardinality</code> parameter only affects metrics collected by integration checks. It does not affect metrics sent through DogStatsD. To configure DogStatsD tag cardinality, use the global <code>dogstatsd_tag_cardinality</code> configuration parameter or the <code>DD_DOGSTATSD_TAG_CARDINALITY</code> environment variable.</div>
+
 ### Validation
 
 To validate your Agent and integrations configuration, [run the Agent's `status` subcommand][28], and look for new configuration under the Checks section.