Merge pull request #21996 from mangulonr/patch-505326

Adding configmap support for Java agent

Author: WriteMayur

src/content/docs/kubernetes-pixie/kubernetes-integration/installation/k8s-agent-operator.mdx

@@ -400,7 +400,9 @@ spec:
     image: newrelic/newrelic-dotnet-init:latest
 ...
 ```
-### APM configuration parameters [#apm-config-parameters]
+### APM configuration [#apm-config-parameters]
+
+#### Using environment variables
 
 The instrumentation CR provides the capability to inject environment variables in the pod to streamline the configuration of the APM agents. See this example:
 
@@ -431,6 +433,26 @@ In the above example, we show you how you can configure the agent settings globa
   You can inject these environment variables in the app deployment manifest.
 </Callout>
 
+#### Using a configmap (Java only)
+
+When using the configmap, note the following requirements: 
+
+- The Java configuration must be stored in a key named `newrelic.yaml`. 
+- Setting the application name or license key in the `configmap` is not supported. 
+- To set these properties, use environment variables or custom secrets instead.
+
+
+```yaml
+apiVersion: newrelic.com/v1beta2
+kind: Instrumentation
+metadata:
+  name: newrelic-instrumentation-java
+  namespace: newrelic
+spec:
+  agentConfigMap: "my-java-app-config" # This configmap must exist in every namespace that the pod in this `Instrumentation` is targeting
+  agent: ...
+```
+
 ### License keys (optional) [#license-keys]
 
 When you install it, a <InlinePopover type="licenseKey"/> is created and it's the license by default. Follow these steps, if you need to send the APM telemetry to a different account: