RFE-5434: Add cluster ID and timestamp to must-gather directory name

pkg/cli/admin/mustgather/mustgather.go

@@ -41,6 +41,7 @@ import (
 	"k8s.io/kubectl/pkg/scheme"
 	"k8s.io/kubectl/pkg/util/templates"
 	admissionapi "k8s.io/pod-security-admission/api"
+	"k8s.io/utils/clock"
 	"k8s.io/utils/exec"
 	utilptr "k8s.io/utils/ptr"
 
@@ -73,7 +74,9 @@ var (
 	`)
 
 	mustGatherExample = templates.Examples(`
-		# Gather information using the default plug-in image and command, writing into ./must-gather.local.<rand>
+		# Gather information using the default plug-in image and command, writing into
+		# ./must-gather.local.<cluster-id-suffix>.<timestamp>.<rand>
+		# or ./must-gather.local.<timestamp>.<rand> if the cluster ID is unavailable
 		  oc adm must-gather
 
 		# Gather information with a specific local folder to copy to
@@ -230,7 +233,7 @@ func (o *MustGatherOptions) Complete(f kcmdutil.Factory, cmd *cobra.Command, arg
 		}
 	}
 	if len(o.DestDir) == 0 {
-		o.DestDir = fmt.Sprintf("must-gather.local.%06d", rand.Int63())
+		o.DestDir = o.generateDestDir(context.TODO())
 	}
 	// TODO: this should be in Validate() method, but added here because of the call to o.completeImages() below
 	if o.AllImages {
@@ -266,6 +269,46 @@ func (o *MustGatherOptions) Complete(f kcmdutil.Factory, cmd *cobra.Command, arg
 	return nil
 }
 
+// generateDestDir builds the default destination directory name for must-gather output.
+// The format includes a partial cluster ID (last 12 characters), a UTC timestamp, and a
+// random ID to help distinguish must-gather archives from different clusters and collection
+// times. If the cluster ID cannot be retrieved (e.g. cluster is unreachable), it falls back
+// to the timestamp and random ID only.
+func (o *MustGatherOptions) getClock() clock.PassiveClock {
+	if o.clock != nil {
+		return o.clock
+	}
+	return clock.RealClock{}
+}
+
+// See: https://issues.redhat.com/browse/RFE-5434
+func (o *MustGatherOptions) generateDestDir(ctx context.Context) string {
+	clusterIDSuffix := ""
+	if o.ConfigClient != nil {
+		lookupCtx, cancel := context.WithTimeout(ctx, 5*time.Second)
+		defer cancel()
+		cv, err := o.ConfigClient.ConfigV1().ClusterVersions().Get(lookupCtx, "version", metav1.GetOptions{})
+		if err == nil {
+			id := string(cv.Spec.ClusterID)
+			if len(id) >= 12 {
+				clusterIDSuffix = id[len(id)-12:]
+			} else if len(id) > 0 {
+				clusterIDSuffix = id
+			}
+		} else {
+			klog.V(4).Infof("unable to retrieve cluster ID for directory name: %v", err)
+		}
+	}
+
+	timestamp := o.getClock().Now().UTC().Format("20060102T150405Z")
+	randID := rand.Int63()
+
+	if clusterIDSuffix != "" {
+		return fmt.Sprintf("must-gather.local.%s.%s.%06d", clusterIDSuffix, timestamp, randID)
+	}
+	return fmt.Sprintf("must-gather.local.%s.%06d", timestamp, randID)
+}
+
 func (o *MustGatherOptions) completeImages(ctx context.Context) error {
 	for _, imageStream := range o.ImageStreams {
 		if image, err := o.resolveImageStreamTagString(ctx, imageStream); err == nil {
@@ -398,6 +441,7 @@ type MustGatherOptions struct {
 	SinceTime        string
 
 	RsyncRshCmd string
+	clock       clock.PassiveClock
 
 	PrinterCreated printers.ResourcePrinter
 	PrinterDeleted printers.ResourcePrinter

pkg/cli/admin/mustgather/mustgather_test.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"path"
 	"reflect"
+	"strings"
 	"testing"
 	"time"
 
@@ -28,6 +29,80 @@ import (
 	imageclient "github.com/openshift/client-go/image/clientset/versioned/fake"
 )
 
+// fakeClock implements clock.PassiveClock for deterministic tests.
+type fakeClock struct {
+	t time.Time
+}
+
+func (f fakeClock) Now() time.Time                   { return f.t }
+func (f fakeClock) Since(ts time.Time) time.Duration { return f.t.Sub(ts) }
+
+func TestGenerateDestDir(t *testing.T) {
+	fixedTime := time.Date(2026, 4, 14, 12, 0, 0, 0, time.UTC)
+	fc := fakeClock{t: fixedTime}
+
+	tests := []struct {
+		name           string
+		clusterID      string
+		expectedPrefix string
+	}{
+		{
+			name:           "with full cluster ID includes last 12 chars",
+			clusterID:      "0194fffc-f70a-4776-b00d-76708af6b91c",
+			expectedPrefix: "must-gather.local.76708af6b91c.20260414T120000Z.",
+		},
+		{
+			name:           "with short cluster ID uses full ID",
+			clusterID:      "abcdef",
+			expectedPrefix: "must-gather.local.abcdef.20260414T120000Z.",
+		},
+		{
+			name:           "without cluster ID falls back gracefully",
+			expectedPrefix: "must-gather.local.20260414T120000Z.",
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			var configObjects []runtime.Object
+			if tc.clusterID != "" {
+				configObjects = []runtime.Object{
+					&configv1.ClusterVersion{
+						ObjectMeta: metav1.ObjectMeta{Name: "version"},
+						Spec: configv1.ClusterVersionSpec{
+							ClusterID: configv1.ClusterID(tc.clusterID),
+						},
+					},
+				}
+			}
+			options := MustGatherOptions{
+				IOStreams:    genericiooptions.NewTestIOStreamsDiscard(),
+				ConfigClient: configv1fake.NewSimpleClientset(configObjects...),
+				clock:        fc,
+			}
+			destDir := options.generateDestDir(context.TODO())
+			if !strings.HasPrefix(destDir, tc.expectedPrefix) {
+				t.Errorf("expected prefix %q, got %q", tc.expectedPrefix, destDir)
+			}
+		})
+	}
+}
+
+func TestGenerateDestDirNoConfigClient(t *testing.T) {
+	fixedTime := time.Date(2026, 4, 14, 12, 0, 0, 0, time.UTC)
+	fc := fakeClock{t: fixedTime}
+
+	options := MustGatherOptions{
+		IOStreams:    genericiooptions.NewTestIOStreamsDiscard(),
+		ConfigClient: nil,
+		clock:        fc,
+	}
+	destDir := options.generateDestDir(context.TODO())
+	if !strings.HasPrefix(destDir, "must-gather.local.20260414T120000Z.") {
+		t.Errorf("expected prefix 'must-gather.local.20260414T120000Z.', got %q", destDir)
+	}
+}
+
 func TestImagesAndImageStreams(t *testing.T) {
 
 	testCases := []struct {