introduce how to configure environment variable for OTEL trace

Author: CasperLiu

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

@@ -22,6 +22,9 @@ with the gRPC exporter and can be collected and routed to tracing backends using
 
 ## Trace Collection
 
+Kubernetes components have built-in grpc exporters for OTLP to export traces, either with an OpenTelemetry Collector, 
+or without an OpenTelemetry Collector.
+
 For a complete guide to collecting traces and using the collector, see
 [Getting Started with the OpenTelemetry Collector](https://opentelemetry.io/docs/collector/getting-started/).
 However, there are a few things to note that are specific to Kubernetes components.
@@ -47,6 +50,44 @@ service:
       exporters: [logging]
 ```
 
+To directly emit traces to a backend without utilizing a collector, 
+specify the endpoint field in the Kubernetes TracingConfiguration with the desired trace backend address. 
+This method negates the need for a collector and simplifies the overall structure.
+
+For trace backend header configuration, including authentication details, environment variables can be used with `OTEL_EXPORTER_OTLP_HEADERS`, 
+see [OTLP Exporter Configuration](https://opentelemetry.io/docs/languages/sdk-configuration/otlp-exporter/).
+
+Additionally, for trace resource attribute configuration such as Kubernetes cluster name, namespace, Pod name, etc., 
+environment variables can also be used with `OTEL_RESOURCE_ATTRIBUTES`, see [OTLP Kubernetes Resource](https://opentelemetry.io/docs/specs/semconv/resource/k8s/).
+
+Below is an example that shows how to configure  to emit traces directly to a backend.
+```yaml
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: apiserver
+  labels:
+    component: apiserver
+spec:
+  selector:
+    matchLabels:
+      component: apiserver
+  template:
+    metadata:
+      labels:
+        component: apiserver
+    spec:
+      containers:
+      - name: apiserver
+        env:
+          - name: OTEL_EXPORTER_OTLP_HEADERS
+            value: "<header_key1>=<header_value1>,<header_key2>=<header_value2>"
+          - name: OTEL_RESOURCE_ATTRIBUTES
+            value: "<resource_key1>=<resource_value1>,<resource_key1>=<resource_value1>"
+```
+Note: Replace header_key, header_value, resource_key, resource_value with your actual keys and values.
+
+
 ## Component traces
 
 ### kube-apiserver traces
@@ -125,4 +166,6 @@ there are no guarantees of backwards compatibility for tracing instrumentation.
 ## {{% heading "whatsnext" %}}
 
 * Read about [Getting Started with the OpenTelemetry Collector](https://opentelemetry.io/docs/collector/getting-started/)
+* Read about [OTLP Exporter Configuration](https://opentelemetry.io/docs/languages/sdk-configuration/otlp-exporter/)
+