HDDS-11929. [Website v2] [Docs] [Administrator Guide] Tracking Metrics With Prometheus.

Author: jojochuang

docs/05-administrator-guide/03-operations/09-observability/04-prometheus.md

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 # Tracking Metrics With Prometheus
 
-**TODO:** File a subtask under [HDDS-9859](https://issues.apache.org/jira/browse/HDDS-9859) and complete this page or section.
+Ozone has native support for Prometheus integration. All internal metrics (collected by Hadoop metrics framework) are published under the `/prom` HTTP endpoint. (For example under http://localhost:9876/prom for SCM).
+
+The Prometheus endpoint is turned on by default but can be turned off by the `hdds.prometheus.endpoint.enabled` configuration variable.
+
+In a secure environment the page is guarded with SPNEGO authentication which is not supported by Prometheus. To enable monitoring in a secure environment, a specific authentication token can be configured
+
+Example `ozone-site.xml`:
+
+```XML
+<property>
+   <name>hdds.prometheus.endpoint.token</name>
+   <value>putyourtokenhere</value>
+</property>
+```
+
+Example prometheus configuration:
+
+```YAML
+scrape_configs:
+  - job_name: ozone
+    bearer_token: <putyourtokenhere>
+    metrics_path: /prom
+    static_configs:
+     - targets:
+         - "127.0.0.1:9876"
+```