Refactor: Extract schedulable worker nodes logic to reusable utility function

As suggested in code review, created a shared utility function
GetReadySchedulableWorkerNodes() in test/extended/node/node_utils.go
to encapsulate the logic of retrieving schedulable worker nodes
(excluding nodes with NoSchedule/NoExecute taints).

This makes the node selection logic reusable across multiple tests
and improves code maintainability.

Changes:
- Added GetReadySchedulableWorkerNodes() in test/extended/node/node_utils.go
- Refactored PinnedImages test to use the new utility function
- Simplified addWorkerNodesToCustomPool() by removing manual filtering logic

Author: bshaw7

test/extended/machine_config/pinnedimages.go

@@ -13,6 +13,7 @@ import (
 
 	mcfgv1 "github.com/openshift/api/machineconfiguration/v1"
 	mcClient "github.com/openshift/client-go/machineconfiguration/clientset/versioned"
+	nodeutil "github.com/openshift/origin/test/extended/node"
 	exutil "github.com/openshift/origin/test/extended/util"
 	corev1 "k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
@@ -21,7 +22,6 @@ import (
 	"k8s.io/apimachinery/pkg/util/wait"
 	"k8s.io/client-go/kubernetes"
 	"k8s.io/kubernetes/test/e2e/framework"
-	e2enode "k8s.io/kubernetes/test/e2e/framework/node"
 	"sigs.k8s.io/yaml"
 )
 
@@ -354,20 +354,12 @@ func applyPIS(oc *exutil.CLI, pisFixture string, pis *mcfgv1.PinnedImageSet, pis
 // `addWorkerNodesToCustomPool` labels the desired number of worker nodes with the MCP role
 // selector so that the nodes become part of the desired custom MCP
 func addWorkerNodesToCustomPool(oc *exutil.CLI, kubeClient *kubernetes.Clientset, numberOfNodes int, customMCP string) ([]string, error) {
-	// Get ready schedulable nodes (excludes nodes with NoSchedule/NoExecute taints)
-	nodes, err := e2enode.GetReadySchedulableNodes(context.TODO(), kubeClient)
+	// Get ready schedulable worker nodes (excludes nodes with NoSchedule/NoExecute taints)
+	workerNodes, err := nodeutil.GetReadySchedulableWorkerNodes(context.TODO(), kubeClient)
 	if err != nil {
 		return nil, err
 	}
 
-	// Filter for worker nodes only
-	var workerNodes []corev1.Node
-	for _, node := range nodes.Items {
-		if _, hasWorkerLabel := node.Labels["node-role.kubernetes.io/worker"]; hasWorkerLabel {
-			workerNodes = append(workerNodes, node)
-		}
-	}
-
 	// Return an error if there are less schedulable worker nodes than the desired number of nodes to add to the custom MCP
 	if len(workerNodes) < numberOfNodes {
 		return nil, fmt.Errorf("Schedulable nodes in Worker MCP %d < Number of nodes needed in %s MCP %d", len(workerNodes), customMCP, numberOfNodes)

test/extended/node/node_utils.go

@@ -7,8 +7,10 @@ import (
 
 	v1 "k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/client-go/kubernetes"
 	kubeletconfigv1beta1 "k8s.io/kubelet/config/v1beta1"
 	"k8s.io/kubernetes/test/e2e/framework"
+	e2enode "k8s.io/kubernetes/test/e2e/framework/node"
 
 	exutil "github.com/openshift/origin/test/extended/util"
 )
@@ -81,3 +83,24 @@ func getPureWorkerNodes(nodes []v1.Node) []v1.Node {
 	}
 	return pureWorkers
 }
+
+// GetReadySchedulableWorkerNodes returns ready schedulable worker nodes.
+// This function filters out nodes with NoSchedule/NoExecute taints and non-worker nodes,
+// making it suitable for tests that need to select worker nodes for workload placement.
+func GetReadySchedulableWorkerNodes(ctx context.Context, client kubernetes.Interface) ([]v1.Node, error) {
+	// Get ready schedulable nodes (excludes nodes with NoSchedule/NoExecute taints)
+	nodes, err := e2enode.GetReadySchedulableNodes(ctx, client)
+	if err != nil {
+		return nil, err
+	}
+
+	// Filter for worker nodes only
+	var workerNodes []v1.Node
+	for _, node := range nodes.Items {
+		if _, hasWorkerLabel := node.Labels["node-role.kubernetes.io/worker"]; hasWorkerLabel {
+			workerNodes = append(workerNodes, node)
+		}
+	}
+
+	return workerNodes, nil
+}