add to cluster-admin/system-traces docs

content/en/docs/concepts/cluster-administration/system-traces.md

@@ -9,7 +9,8 @@ weight: 60
 
 <!-- overview -->
 
-{{< feature-state for_k8s_version="v1.22" state="alpha" >}}
+{{< feature-state for_k8s_version="v1.22, kube-apiserver" state="alpha" >}}
+{{< feature-state for_k8s_version="v1.25, kubelet" state="alpha" >}}
 
 System component traces record the latency of and relationships between operations in the cluster.
 
@@ -61,7 +62,7 @@ as the kube-apiserver is often a public endpoint.
 
 To enable tracing, enable the `APIServerTracing`
 [feature gate](/docs/reference/command-line-tools-reference/feature-gates/)
-on the kube-apiserver. Also, provide the kube-apiserver with a tracing configration file
+on the kube-apiserver. Also, provide the kube-apiserver with a tracing configuration file
 with `--tracing-config-file=<path-to-config>`. This is an example config that records
 spans for 1 in 10000 requests, and uses the default OpenTelemetry endpoint:
 
@@ -76,6 +77,30 @@ samplingRatePerMillion: 100
 For more information about the `TracingConfiguration` struct, see
 [API server config API (v1alpha1)](/docs/reference/config-api/apiserver-config.v1alpha1/#apiserver-k8s-io-v1alpha1-TracingConfiguration).
 
+### kubelet traces
+
+The kubelet CRI interface and authenticated http servers are instrumented to generate
+trace spans. As with the apiserver, the endpoint and sampling rate are configurable.
+Trace context propagation is also configured.
+
+#### Enabling tracing in the kubelet
+
+To enable tracing, enable the `KubeletTracing`
+[feature gate](/docs/reference/command-line-tools-reference/feature-gates/)
+on the kubelet. Also, provide the kubelet with a
+[tracing configuration](https://github.com/kubernetes/component-base/blob/master/tracing/api/v1/types.go).
+This is an example snippet of a kubelet config that records spans for 1 in 10000 requests, and uses the default OpenTelemetry endpoint:
+
+```yaml
+apiVersion: kubelet.config.k8s.io/v1beta1
+kind: KubeletConfiguration
+featureGates:
+  KubeletTracing: true
+tracing:
+  endpoint: 127.0.0.1:4317
+  samplingRatePerMillion: 100
+```
+
 ## Stability
 
 Tracing instrumentation is still under active development, and may change