review fixes

Author: sbueringer

test/e2e/cluster_upgrade_runtimesdk.go

@@ -120,8 +120,13 @@ func clusterUpgradeWithRuntimeSDKSpec(ctx context.Context, inputGetter func() cl
 		By("Deploy Test Extension")
 		testExtensionDeploymentTemplate, err := os.ReadFile(testExtensionPath) //nolint:gosec
 		Expect(err).ToNot(HaveOccurred(), "Failed to read the extension config deployment manifest file")
+
+		// Set the SERVICE_NAMESPACE, which is used in the cert-manager Certificate CR.
+		// We have to dynamically set the namespace here, because it depends on the test run and thus
+		// cannot be set when rendering the test extension YAML with kustomize.
 		testExtensionDeployment := strings.ReplaceAll(string(testExtensionDeploymentTemplate), "${SERVICE_NAMESPACE}", namespace.Name)
 		Expect(testExtensionDeployment).ToNot(BeEmpty(), "Test Extension deployment manifest file should not be empty")
+
 		Expect(input.BootstrapClusterProxy.Apply(ctx, []byte(testExtensionDeployment), "--namespace", namespace.Name)).To(Succeed())
 
 		By("Deploy Test Extension ExtensionConfig")
@@ -151,6 +156,7 @@ func clusterUpgradeWithRuntimeSDKSpec(ctx context.Context, inputGetter func() cl
 			WaitForMachinePools:          input.E2EConfig.GetIntervals(specName, "wait-machine-pool-nodes"),
 		}, clusterResources)
 
+		// Upgrade the Cluster topology to run through an entire cluster lifecycle to test the lifecycle hooks.
 		By("Upgrading the Cluster topology")
 		framework.UpgradeClusterTopologyAndWaitForUpgrade(ctx, framework.UpgradeClusterTopologyAndWaitForUpgradeInput{
 			ClusterProxy:                input.BootstrapClusterProxy,
@@ -201,6 +207,10 @@ func clusterUpgradeWithRuntimeSDKSpec(ctx context.Context, inputGetter func() cl
 	})
 }
 
+// extensionConfig generates an ExtensionConfig.
+// We make sure this cluster-wide object does not conflict with others by using a random generated
+// name and a NamespaceSelector selecting on the namespace of the current test.
+// Thus, this object is "namespaced" to the current test even though it's a cluster-wide object.
 func extensionConfig(specName string, namespace *corev1.Namespace) *runtimev1.ExtensionConfig {
 	return &runtimev1.ExtensionConfig{
 		ObjectMeta: metav1.ObjectMeta{