Add contents

content/en/docs/reference/instrumentation/zpages.md

@@ -1,7 +1,76 @@
 ---
+reviewers:
+- richabanker
 title: Kubernetes z-pages Reference
 content_type: reference
-auto_generated: true
-description: >-
-  Details of the zpages data that Kubernetes components expose.
----
+weight: 20
+---
+
+<!-- overview -->
+
+{{< feature-state for_k8s_version="v1.32" state="alpha" >}}
+
+By default, Kubernetes {{< skew currentVersion >}} publishes Service Level Indicator (SLI) metrics 
+for each Kubernetes component binary. This metric endpoint is exposed on the serving 
+HTTPS port of each component, at the path `/metrics/slis`. The 
+`ComponentSLIs` [feature gate](/docs/reference/command-line-tools-reference/feature-gates/)
+defaults to enabled for each Kubernetes component as of v1.27.
+
+<!-- body -->
+
+## z-pages
+
+A suite of z-endpoints to enhance debuggability of Kubernetes control plane components. Currently we have the following components:
+
+1. flagz
+2. statusz
+
+### flagz
+
+With ComponentFlagz enabled, each Kubernetes component exposes a new /flagz endpoint.
+
+You can use this endpoint to ...
+
+The flagz data for apiserver looks like this:
+
+```
+kube-apiserver flags
+Warning: This endpoint is not meant to be machine parseable, has no formatting compatibility guarantees and is for debugging purposes only.
+
+advertise-address=192.168.8.2
+contention-profiling=false
+enable-priority-and-fairness=true
+profiling=true
+authorization-mode=[Node,RBAC]
+authorization-webhook-cache-authorized-ttl=5m0s
+authorization-webhook-cache-unauthorized-ttl=30s
+authorization-webhook-version=v1beta1
+default-watch-cache-size=100
+```
+
+#### Using flagz
+
+This endpoint is only meant to be used for debugging purposes when the user wants to quickly know which command line flags was the component binary started with. This endpoint is not meant to be scraped with the expectation that the contents returned by this endpoint are stable.
+
+### statusz
+
+With ComponentStatusz enabled, each Kubernetes component exposes a new /statusz endpoint.
+
+You can use this endpoint to ...
+
+The statusz data for apiserver looks like this:
+
+```
+kube-apiserver statusz
+Warning: This endpoint is not meant to be machine parseable, has no formatting compatibility guarantees and is for debugging purposes only.
+
+Started: Wed Oct 16 21:03:43 UTC 2024
+Up: 0 hr 00 min 16 sec
+Go version: go1.23.2
+Binary version: 1.32.0-alpha.0.1484&#43;5eeac4f21a491b-dirty
+Emulation version: 1.32.0-alpha.0.1484
+```
+
+#### Using statusz
+
+This endpoint is only meant to be used for debugging purposes when the user wants to quickly know high level information for the component, for ex. the Kubernetes version it is at, its emulation version, its start time details etc. This endpoint is not meant to be scraped with the expectation that the contents returned by this endpoint are stable.