Fix overscaling when the controller is much faster then the listener (#3371)

Co-authored-by: Francesco Renzi <rentziass@gmail.com>

apis/actions.github.com/v1alpha1/ephemeralrunner_types.go

@@ -42,6 +42,10 @@ type EphemeralRunner struct {
 	Status EphemeralRunnerStatus `json:"status,omitempty"`
 }
 
+func (er *EphemeralRunner) IsDone() bool {
+	return er.Status.Phase == corev1.PodSucceeded || er.Status.Phase == corev1.PodFailed
+}
+
 // EphemeralRunnerSpec defines the desired state of EphemeralRunner
 type EphemeralRunnerSpec struct {
 	// INSERT ADDITIONAL SPEC FIELDS - desired state of cluster

apis/actions.github.com/v1alpha1/ephemeralrunnerset_types.go

@@ -24,6 +24,8 @@ import (
 type EphemeralRunnerSetSpec struct {
 	// Replicas is the number of desired EphemeralRunner resources in the k8s namespace.
 	Replicas int `json:"replicas,omitempty"`
+	// PatchID is the unique identifier for the patch issued by the listener app
+	PatchID int `json:"patchID"`
 
 	EphemeralRunnerSpec EphemeralRunnerSpec `json:"ephemeralRunnerSpec,omitempty"`
 }

charts/gha-runner-scale-set-controller/crds/actions.github.com_ephemeralrunnersets.yaml

@@ -6957,9 +6957,14 @@ spec:
                         - containers
                       type: object
                   type: object
+                patchID:
+                  description: PatchID is the unique identifier for the patch issued by the listener app
+                  type: integer
                 replicas:
                   description: Replicas is the number of desired EphemeralRunner resources in the k8s namespace.
                   type: integer
+              required:
+                - patchID
               type: object
             status:
               description: EphemeralRunnerSetStatus defines the observed state of EphemeralRunnerSet

cmd/ghalistener/app/app.go

@@ -34,7 +34,7 @@ type Listener interface {
 //go:generate mockery --name Worker --output ./mocks --outpkg mocks --case underscore
 type Worker interface {
 	HandleJobStarted(ctx context.Context, jobInfo *actions.JobStarted) error
-	HandleDesiredRunnerCount(ctx context.Context, count int) (int, error)
+	HandleDesiredRunnerCount(ctx context.Context, count int, jobsCompleted int) (int, error)
 }
 
 func New(config config.Config) (*App, error) {

cmd/ghalistener/app/mocks/worker.go

@@ -15,23 +15,23 @@ type Worker struct {
 	mock.Mock
 }
 
-// HandleDesiredRunnerCount provides a mock function with given fields: ctx, count
+// HandleDesiredRunnerCount provides a mock function with given fields: ctx, count, acquireCount
-func (_m *Worker) HandleDesiredRunnerCount(ctx context.Context, count int) (int, error) {
+func (_m *Worker) HandleDesiredRunnerCount(ctx context.Context, count int, acquireCount int) (int, error) {
-	ret := _m.Called(ctx, count)
+	ret := _m.Called(ctx, count, acquireCount)
 
 	var r0 int
 	var r1 error
-	if rf, ok := ret.Get(0).(func(context.Context, int) (int, error)); ok {
+	if rf, ok := ret.Get(0).(func(context.Context, int, int) (int, error)); ok {
-		return rf(ctx, count)
+		return rf(ctx, count, acquireCount)
 	}
-	if rf, ok := ret.Get(0).(func(context.Context, int) int); ok {
+	if rf, ok := ret.Get(0).(func(context.Context, int, int) int); ok {
-		r0 = rf(ctx, count)
+		r0 = rf(ctx, count, acquireCount)
 	} else {
 		r0 = ret.Get(0).(int)
 	}
 
-	if rf, ok := ret.Get(1).(func(context.Context, int) error); ok {
+	if rf, ok := ret.Get(1).(func(context.Context, int, int) error); ok {
-		r1 = rf(ctx, count)
+		r1 = rf(ctx, count, acquireCount)
 	} else {
 		r1 = ret.Error(1)
 	}

cmd/ghalistener/listener/listener.go

@@ -114,7 +114,7 @@ func New(config Config) (*Listener, error) {
 //go:generate mockery --name Handler --output ./mocks --outpkg mocks --case underscore
 type Handler interface {
 	HandleJobStarted(ctx context.Context, jobInfo *actions.JobStarted) error
-	HandleDesiredRunnerCount(ctx context.Context, count int) (int, error)
+	HandleDesiredRunnerCount(ctx context.Context, count, jobsCompleted int) (int, error)
 }
 
 // Listen listens for incoming messages and handles them using the provided handler.
@@ -145,7 +145,7 @@ func (l *Listener) Listen(ctx context.Context, handler Handler) error {
 	}
 	l.metrics.PublishStatistics(initialMessage.Statistics)
 
-	desiredRunners, err := handler.HandleDesiredRunnerCount(ctx, initialMessage.Statistics.TotalAssignedJobs)
+	desiredRunners, err := handler.HandleDesiredRunnerCount(ctx, initialMessage.Statistics.TotalAssignedJobs, 0)
 	if err != nil {
 		return fmt.Errorf("handling initial message failed: %w", err)
 	}
@@ -207,7 +207,7 @@ func (l *Listener) handleMessage(ctx context.Context, handler Handler, msg *acti
 		l.metrics.PublishJobStarted(jobStarted)
 	}
 
-	desiredRunners, err := handler.HandleDesiredRunnerCount(ctx, parsedMsg.statistics.TotalAssignedJobs)
+	desiredRunners, err := handler.HandleDesiredRunnerCount(ctx, parsedMsg.statistics.TotalAssignedJobs, len(parsedMsg.jobsCompleted))
 	if err != nil {
 		return fmt.Errorf("failed to handle desired runner count: %w", err)
 	}
@@ -284,7 +284,6 @@ func (l *Listener) getMessage(ctx context.Context) (*actions.RunnerScaleSetMessa
 	}
 
 	return msg, nil
-
 }
 
 func (l *Listener) deleteLastMessage(ctx context.Context) error {

cmd/ghalistener/listener/listener_test.go

@@ -427,7 +427,7 @@ func TestListener_Listen(t *testing.T) {
 
 		var called bool
 		handler := listenermocks.NewHandler(t)
-		handler.On("HandleDesiredRunnerCount", mock.Anything, mock.Anything).
+		handler.On("HandleDesiredRunnerCount", mock.Anything, mock.Anything, 0).
 			Return(0, nil).
 			Run(
 				func(mock.Arguments) {
@@ -485,11 +485,11 @@ func TestListener_Listen(t *testing.T) {
 		config.Client = client
 
 		handler := listenermocks.NewHandler(t)
-		handler.On("HandleDesiredRunnerCount", mock.Anything, mock.Anything).
+		handler.On("HandleDesiredRunnerCount", mock.Anything, mock.Anything, 0).
 			Return(0, nil).
 			Once()
 
-		handler.On("HandleDesiredRunnerCount", mock.Anything, mock.Anything).
+		handler.On("HandleDesiredRunnerCount", mock.Anything, mock.Anything, 0).
 			Return(0, nil).
 			Once()
 

cmd/ghalistener/listener/metrics_test.go

@@ -86,7 +86,7 @@ func TestInitialMetrics(t *testing.T) {
 		config.Client = client
 
 		handler := listenermocks.NewHandler(t)
-		handler.On("HandleDesiredRunnerCount", mock.Anything, sessionStatistics.TotalAssignedJobs).
+		handler.On("HandleDesiredRunnerCount", mock.Anything, sessionStatistics.TotalAssignedJobs, 0).
 			Return(sessionStatistics.TotalAssignedJobs, nil).
 			Once()
 
@@ -178,7 +178,7 @@ func TestHandleMessageMetrics(t *testing.T) {
 
 	handler := listenermocks.NewHandler(t)
 	handler.On("HandleJobStarted", mock.Anything, jobsStarted[0]).Return(nil).Once()
-	handler.On("HandleDesiredRunnerCount", mock.Anything, mock.Anything).Return(desiredResult, nil).Once()
+	handler.On("HandleDesiredRunnerCount", mock.Anything, mock.Anything, 2).Return(desiredResult, nil).Once()
 
 	client := listenermocks.NewClient(t)
 	client.On("DeleteMessage", mock.Anything, mock.Anything, mock.Anything, mock.Anything).Return(nil).Once()

cmd/ghalistener/listener/mocks/handler.go

@@ -15,23 +15,23 @@ type Handler struct {
 	mock.Mock
 }
 
-// HandleDesiredRunnerCount provides a mock function with given fields: ctx, count
+// HandleDesiredRunnerCount provides a mock function with given fields: ctx, count, jobsCompleted
-func (_m *Handler) HandleDesiredRunnerCount(ctx context.Context, count int) (int, error) {
+func (_m *Handler) HandleDesiredRunnerCount(ctx context.Context, count int, jobsCompleted int) (int, error) {
-	ret := _m.Called(ctx, count)
+	ret := _m.Called(ctx, count, jobsCompleted)
 
 	var r0 int
 	var r1 error
-	if rf, ok := ret.Get(0).(func(context.Context, int) (int, error)); ok {
+	if rf, ok := ret.Get(0).(func(context.Context, int, int) (int, error)); ok {
-		return rf(ctx, count)
+		return rf(ctx, count, jobsCompleted)
 	}
-	if rf, ok := ret.Get(0).(func(context.Context, int) int); ok {
+	if rf, ok := ret.Get(0).(func(context.Context, int, int) int); ok {
-		r0 = rf(ctx, count)
+		r0 = rf(ctx, count, jobsCompleted)
 	} else {
 		r0 = ret.Get(0).(int)
 	}
 
-	if rf, ok := ret.Get(1).(func(context.Context, int) error); ok {
+	if rf, ok := ret.Get(1).(func(context.Context, int, int) error); ok {
-		r1 = rf(ctx, count)
+		r1 = rf(ctx, count, jobsCompleted)
 	} else {
 		r1 = ret.Error(1)
 	}

cmd/ghalistener/worker/worker.go

@@ -38,18 +38,20 @@ type Config struct {
 // The Worker's role is to process the messages it receives from the listener.
 // It then initiates Kubernetes API requests to carry out the necessary actions.
 type Worker struct {
-	clientset *kubernetes.Clientset
+	clientset   *kubernetes.Clientset
-	config    Config
+	config      Config
-	lastPatch int
+	lastPatch   int
-	logger    *logr.Logger
+	lastPatchID int
+	logger      *logr.Logger
 }
 
 var _ listener.Handler = (*Worker)(nil)
 
 func New(config Config, options ...Option) (*Worker, error) {
 	w := &Worker{
-		config:    config,
+		config:      config,
-		lastPatch: -1,
+		lastPatch:   -1,
+		lastPatchID: -1,
 	}
 
 	conf, err := rest.InClusterConfig()
@@ -161,7 +163,7 @@ func (w *Worker) HandleJobStarted(ctx context.Context, jobInfo *actions.JobStart
 // The function then scales the ephemeral runner set by applying the merge patch.
 // Finally, it logs the scaled ephemeral runner set details and returns nil if successful.
 // If any error occurs during the process, it returns an error with a descriptive message.
-func (w *Worker) HandleDesiredRunnerCount(ctx context.Context, count int) (int, error) {
+func (w *Worker) HandleDesiredRunnerCount(ctx context.Context, count int, jobsCompleted int) (int, error) {
 	// Max runners should always be set by the resource builder either to the configured value,
 	// or the maximum int32 (resourcebuilder.newAutoScalingListener()).
 	targetRunnerCount := min(w.config.MinRunners+count, w.config.MaxRunners)
@@ -172,17 +174,22 @@ func (w *Worker) HandleDesiredRunnerCount(ctx context.Context, count int) (int,
 		"min", w.config.MinRunners,
 		"max", w.config.MaxRunners,
 		"currentRunnerCount", w.lastPatch,
+		"jobsCompleted", jobsCompleted,
 	}
 
-	if targetRunnerCount == w.lastPatch {
+	if w.lastPatch == targetRunnerCount && jobsCompleted == 0 {
-		w.logger.Info("Skipping patching of EphemeralRunnerSet as the desired count has not changed", logValues...)
+		w.logger.Info("Skipping patch", logValues...)
 		return targetRunnerCount, nil
 	}
 
+	w.lastPatchID++
+	w.lastPatch = targetRunnerCount
+
 	original, err := json.Marshal(
 		&v1alpha1.EphemeralRunnerSet{
 			Spec: v1alpha1.EphemeralRunnerSetSpec{
 				Replicas: -1,
+				PatchID:  -1,
 			},
 		},
 	)
@@ -194,6 +201,7 @@ func (w *Worker) HandleDesiredRunnerCount(ctx context.Context, count int) (int,
 		&v1alpha1.EphemeralRunnerSet{
 			Spec: v1alpha1.EphemeralRunnerSetSpec{
 				Replicas: targetRunnerCount,
+				PatchID:  w.lastPatchID,
 			},
 		},
 	)

config/crd/bases/actions.github.com_ephemeralrunnersets.yaml

@@ -6957,9 +6957,14 @@ spec:
                         - containers
                       type: object
                   type: object
+                patchID:
+                  description: PatchID is the unique identifier for the patch issued by the listener app
+                  type: integer
                 replicas:
                   description: Replicas is the number of desired EphemeralRunner resources in the k8s namespace.
                   type: integer
+              required:
+                - patchID
               type: object
             status:
               description: EphemeralRunnerSetStatus defines the observed state of EphemeralRunnerSet

controllers/actions.github.com/constants.go

@@ -42,6 +42,7 @@ const AutoscalingRunnerSetCleanupFinalizerName = "actions.github.com/cleanup-pro
 const (
 	AnnotationKeyGitHubRunnerGroupName    = "actions.github.com/runner-group-name"
 	AnnotationKeyGitHubRunnerScaleSetName = "actions.github.com/runner-scale-set-name"
+	AnnotationKeyPatchID                  = "actions.github.com/patch-id"
 )
 
 // Labels applied to listener roles

controllers/actions.github.com/ephemeralrunner_controller.go

@@ -133,6 +133,23 @@ func (r *EphemeralRunnerReconciler) Reconcile(ctx context.Context, req ctrl.Requ
 		return ctrl.Result{}, nil
 	}
 
+	if ephemeralRunner.IsDone() {
+		log.Info("Cleaning up resources after after ephemeral runner termination", "phase", ephemeralRunner.Status.Phase)
+		done, err := r.cleanupResources(ctx, ephemeralRunner, log)
+		if err != nil {
+			log.Error(err, "Failed to clean up ephemeral runner owned resources")
+			return ctrl.Result{}, err
+		}
+		if !done {
+			log.Info("Waiting for ephemeral runner owned resources to be deleted")
+			return ctrl.Result{Requeue: true}, nil
+		}
+		// Stop reconciling on this object.
+		// The EphemeralRunnerSet is responsible for cleaning it up.
+		log.Info("EphemeralRunner has already finished. Stopping reconciliation and waiting for EphemeralRunnerSet to clean it up", "phase", ephemeralRunner.Status.Phase)
+		return ctrl.Result{}, nil
+	}
+
 	if !controllerutil.ContainsFinalizer(ephemeralRunner, ephemeralRunnerActionsFinalizerName) {
 		log.Info("Adding runner registration finalizer")
 		err := patch(ctx, r.Client, ephemeralRunner, func(obj *v1alpha1.EphemeralRunner) {
@@ -159,13 +176,6 @@ func (r *EphemeralRunnerReconciler) Reconcile(ctx context.Context, req ctrl.Requ
 		return ctrl.Result{}, nil
 	}
 
-	if ephemeralRunner.Status.Phase == corev1.PodSucceeded || ephemeralRunner.Status.Phase == corev1.PodFailed {
-		// Stop reconciling on this object.
-		// The EphemeralRunnerSet is responsible for cleaning it up.
-		log.Info("EphemeralRunner has already finished. Stopping reconciliation and waiting for EphemeralRunnerSet to clean it up", "phase", ephemeralRunner.Status.Phase)
-		return ctrl.Result{}, nil
-	}
-
 	if ephemeralRunner.Status.RunnerId == 0 {
 		log.Info("Creating new ephemeral runner registration and updating status with runner config")
 		return r.updateStatusWithRunnerConfig(ctx, ephemeralRunner, log)
@@ -324,7 +334,7 @@ func (r *EphemeralRunnerReconciler) cleanupResources(ctx context.Context, epheme
 			}
 		}
 		return false, nil
-	case err != nil && !kerrors.IsNotFound(err):
+	case !kerrors.IsNotFound(err):
 		return false, err
 	}
 	log.Info("Pod is deleted")
@@ -341,7 +351,7 @@ func (r *EphemeralRunnerReconciler) cleanupResources(ctx context.Context, epheme
 			}
 		}
 		return false, nil
-	case err != nil && !kerrors.IsNotFound(err):
+	case !kerrors.IsNotFound(err):
 		return false, err
 	}
 	log.Info("Secret is deleted")

controllers/actions.github.com/ephemeralrunnerset_controller.go

@@ -22,6 +22,7 @@ import (
 	"fmt"
 	"net/http"
 	"sort"
+	"strconv"
 	"strings"
 
 	"github.com/actions/actions-runner-controller/apis/actions.github.com/v1alpha1"
@@ -156,14 +157,14 @@ func (r *EphemeralRunnerSetReconciler) Reconcile(ctx context.Context, req ctrl.R
 		return ctrl.Result{}, err
 	}
 
-	pendingEphemeralRunners, runningEphemeralRunners, finishedEphemeralRunners, failedEphemeralRunners, deletingEphemeralRunners := categorizeEphemeralRunners(ephemeralRunnerList)
+	ephemeralRunnerState := newEphemeralRunnerState(ephemeralRunnerList)
 
 	log.Info("Ephemeral runner counts",
-		"pending", len(pendingEphemeralRunners),
+		"pending", len(ephemeralRunnerState.pending),
-		"running", len(runningEphemeralRunners),
+		"running", len(ephemeralRunnerState.running),
-		"finished", len(finishedEphemeralRunners),
+		"finished", len(ephemeralRunnerState.finished),
-		"failed", len(failedEphemeralRunners),
+		"failed", len(ephemeralRunnerState.failed),
-		"deleting", len(deletingEphemeralRunners),
+		"deleting", len(ephemeralRunnerState.deleting),
 	)
 
 	if r.PublishMetrics {
@@ -183,54 +184,52 @@ func (r *EphemeralRunnerSetReconciler) Reconcile(ctx context.Context, req ctrl.R
 				Organization: parsedURL.Organization,
 				Enterprise:   parsedURL.Enterprise,
 			},
-			len(pendingEphemeralRunners),
+			len(ephemeralRunnerState.pending),
-			len(runningEphemeralRunners),
+			len(ephemeralRunnerState.running),
-			len(failedEphemeralRunners),
+			len(ephemeralRunnerState.failed),
 		)
 	}
 
-	// cleanup finished runners and proceed
+	total := ephemeralRunnerState.scaleTotal()
-	var errs []error
+	if ephemeralRunnerSet.Spec.PatchID == 0 || ephemeralRunnerSet.Spec.PatchID != ephemeralRunnerState.latestPatchID {
-	for i := range finishedEphemeralRunners {
+		defer func() {
-		log.Info("Deleting finished ephemeral runner", "name", finishedEphemeralRunners[i].Name)
+			if err := r.cleanupFinishedEphemeralRunners(ctx, ephemeralRunnerState.finished, log); err != nil {
-		if err := r.Delete(ctx, finishedEphemeralRunners[i]); err != nil {
+				log.Error(err, "failed to cleanup finished ephemeral runners")
-			if !kerrors.IsNotFound(err) {
-				errs = append(errs, err)
 			}
-		}
+		}()
-	}
 
-	if len(errs) > 0 {
+		log.Info("Scaling comparison", "current", total, "desired", ephemeralRunnerSet.Spec.Replicas)
-		mergedErrs := multierr.Combine(errs...)
+		switch {
-		log.Error(mergedErrs, "Failed to delete finished ephemeral runners")
+		case total < ephemeralRunnerSet.Spec.Replicas: // Handle scale up
-		return ctrl.Result{}, mergedErrs
+			count := ephemeralRunnerSet.Spec.Replicas - total
-	}
+			log.Info("Creating new ephemeral runners (scale up)", "count", count)
+			if err := r.createEphemeralRunners(ctx, ephemeralRunnerSet, count, log); err != nil {
+				log.Error(err, "failed to make ephemeral runner")
+				return ctrl.Result{}, err
+			}
 
-	total := len(pendingEphemeralRunners) + len(runningEphemeralRunners) + len(failedEphemeralRunners)
+		case total > ephemeralRunnerSet.Spec.Replicas: // Handle scale down scenario.
-	log.Info("Scaling comparison", "current", total, "desired", ephemeralRunnerSet.Spec.Replicas)
+			count := total - ephemeralRunnerSet.Spec.Replicas
-	switch {
+			log.Info("Deleting ephemeral runners (scale down)", "count", count)
-	case total < ephemeralRunnerSet.Spec.Replicas: // Handle scale up
+			if err := r.deleteIdleEphemeralRunners(
-		count := ephemeralRunnerSet.Spec.Replicas - total
+				ctx,
-		log.Info("Creating new ephemeral runners (scale up)", "count", count)
+				ephemeralRunnerSet,
-		if err := r.createEphemeralRunners(ctx, ephemeralRunnerSet, count, log); err != nil {
+				ephemeralRunnerState.pending,
-			log.Error(err, "failed to make ephemeral runner")
+				ephemeralRunnerState.running,
-			return ctrl.Result{}, err
+				count,
-		}
+				log,
-
+			); err != nil {
-	case total > ephemeralRunnerSet.Spec.Replicas: // Handle scale down scenario.
+				log.Error(err, "failed to delete idle runners")
-		count := total - ephemeralRunnerSet.Spec.Replicas
+				return ctrl.Result{}, err
-		log.Info("Deleting ephemeral runners (scale down)", "count", count)
+			}
-		if err := r.deleteIdleEphemeralRunners(ctx, ephemeralRunnerSet, pendingEphemeralRunners, runningEphemeralRunners, count, log); err != nil {
-			log.Error(err, "failed to delete idle runners")
-			return ctrl.Result{}, err
 		}
 	}
 
 	desiredStatus := v1alpha1.EphemeralRunnerSetStatus{
 		CurrentReplicas:         total,
-		PendingEphemeralRunners: len(pendingEphemeralRunners),
+		PendingEphemeralRunners: len(ephemeralRunnerState.pending),
-		RunningEphemeralRunners: len(runningEphemeralRunners),
+		RunningEphemeralRunners: len(ephemeralRunnerState.running),
-		FailedEphemeralRunners:  len(failedEphemeralRunners),
+		FailedEphemeralRunners:  len(ephemeralRunnerState.failed),
 	}
 
 	// Update the status if needed.
@@ -247,6 +246,21 @@ func (r *EphemeralRunnerSetReconciler) Reconcile(ctx context.Context, req ctrl.R
 	return ctrl.Result{}, nil
 }
 
+func (r *EphemeralRunnerSetReconciler) cleanupFinishedEphemeralRunners(ctx context.Context, finishedEphemeralRunners []*v1alpha1.EphemeralRunner, log logr.Logger) error {
+	// cleanup finished runners and proceed
+	var errs []error
+	for i := range finishedEphemeralRunners {
+		log.Info("Deleting finished ephemeral runner", "name", finishedEphemeralRunners[i].Name)
+		if err := r.Delete(ctx, finishedEphemeralRunners[i]); err != nil {
+			if !kerrors.IsNotFound(err) {
+				errs = append(errs, err)
+			}
+		}
+	}
+
+	return multierr.Combine(errs...)
+}
+
 func (r *EphemeralRunnerSetReconciler) cleanUpProxySecret(ctx context.Context, ephemeralRunnerSet *v1alpha1.EphemeralRunnerSet, log logr.Logger) error {
 	if ephemeralRunnerSet.Spec.EphemeralRunnerSpec.Proxy == nil {
 		return nil
@@ -284,19 +298,19 @@ func (r *EphemeralRunnerSetReconciler) cleanUpEphemeralRunners(ctx context.Conte
 		return true, nil
 	}
 
-	pendingEphemeralRunners, runningEphemeralRunners, finishedEphemeralRunners, failedEphemeralRunners, deletingEphemeralRunners := categorizeEphemeralRunners(ephemeralRunnerList)
+	ephemeralRunnerState := newEphemeralRunnerState(ephemeralRunnerList)
 
 	log.Info("Clean up runner counts",
-		"pending", len(pendingEphemeralRunners),
+		"pending", len(ephemeralRunnerState.pending),
-		"running", len(runningEphemeralRunners),
+		"running", len(ephemeralRunnerState.running),
-		"finished", len(finishedEphemeralRunners),
+		"finished", len(ephemeralRunnerState.finished),
-		"failed", len(failedEphemeralRunners),
+		"failed", len(ephemeralRunnerState.failed),
-		"deleting", len(deletingEphemeralRunners),
+		"deleting", len(ephemeralRunnerState.deleting),
 	)
 
 	log.Info("Cleanup finished or failed ephemeral runners")
 	var errs []error
-	for _, ephemeralRunner := range append(finishedEphemeralRunners, failedEphemeralRunners...) {
+	for _, ephemeralRunner := range append(ephemeralRunnerState.finished, ephemeralRunnerState.failed...) {
 		log.Info("Deleting ephemeral runner", "name", ephemeralRunner.Name)
 		if err := r.Delete(ctx, ephemeralRunner); err != nil && !kerrors.IsNotFound(err) {
 			errs = append(errs, err)
@@ -310,7 +324,7 @@ func (r *EphemeralRunnerSetReconciler) cleanUpEphemeralRunners(ctx context.Conte
 	}
 
 	// avoid fetching the client if we have nothing left to do
-	if len(runningEphemeralRunners) == 0 && len(pendingEphemeralRunners) == 0 {
+	if len(ephemeralRunnerState.running) == 0 && len(ephemeralRunnerState.pending) == 0 {
 		return false, nil
 	}
 
@@ -321,7 +335,7 @@ func (r *EphemeralRunnerSetReconciler) cleanUpEphemeralRunners(ctx context.Conte
 
 	log.Info("Cleanup pending or running ephemeral runners")
 	errs = errs[0:0]
-	for _, ephemeralRunner := range append(pendingEphemeralRunners, runningEphemeralRunners...) {
+	for _, ephemeralRunner := range append(ephemeralRunnerState.pending, ephemeralRunnerState.running...) {
 		log.Info("Removing the ephemeral runner from the service", "name", ephemeralRunner.Name)
 		_, err := r.deleteEphemeralRunnerWithActionsClient(ctx, ephemeralRunner, actionsClient, log)
 		if err != nil {
@@ -427,12 +441,13 @@ func (r *EphemeralRunnerSetReconciler) deleteIdleEphemeralRunners(ctx context.Co
 	deletedCount := 0
 	for runners.next() {
 		ephemeralRunner := runners.object()
-		if ephemeralRunner.Status.RunnerId == 0 {
+		isDone := ephemeralRunner.IsDone()
+		if !isDone && ephemeralRunner.Status.RunnerId == 0 {
 			log.Info("Skipping ephemeral runner since it is not registered yet", "name", ephemeralRunner.Name)
 			continue
 		}
 
-		if ephemeralRunner.Status.JobRequestId > 0 {
+		if !isDone && ephemeralRunner.Status.JobRequestId > 0 {
 			log.Info("Skipping ephemeral runner since it is running a job", "name", ephemeralRunner.Name, "jobRequestId", ephemeralRunner.Status.JobRequestId)
 			continue
 		}
@@ -580,16 +595,22 @@ type ephemeralRunnerStepper struct {
 	index int
 }
 
-func newEphemeralRunnerStepper(pending, running []*v1alpha1.EphemeralRunner) *ephemeralRunnerStepper {
+func newEphemeralRunnerStepper(primary []*v1alpha1.EphemeralRunner, othersOrdered ...[]*v1alpha1.EphemeralRunner) *ephemeralRunnerStepper {
-	sort.Slice(pending, func(i, j int) bool {
+	sort.Slice(primary, func(i, j int) bool {
-		return pending[i].GetCreationTimestamp().Time.Before(pending[j].GetCreationTimestamp().Time)
+		return primary[i].GetCreationTimestamp().Time.Before(primary[j].GetCreationTimestamp().Time)
-	})
-	sort.Slice(running, func(i, j int) bool {
-		return running[i].GetCreationTimestamp().Time.Before(running[j].GetCreationTimestamp().Time)
 	})
+	for _, bucket := range othersOrdered {
+		sort.Slice(bucket, func(i, j int) bool {
+			return bucket[i].GetCreationTimestamp().Time.Before(bucket[j].GetCreationTimestamp().Time)
+		})
+	}
+
+	for _, bucket := range othersOrdered {
+		primary = append(primary, bucket...)
+	}
 
 	return &ephemeralRunnerStepper{
-		items: append(pending, running...),
+		items: primary,
 		index: -1,
 	}
 }
@@ -613,28 +634,48 @@ func (s *ephemeralRunnerStepper) len() int {
 	return len(s.items)
 }
 
-func categorizeEphemeralRunners(ephemeralRunnerList *v1alpha1.EphemeralRunnerList) (pendingEphemeralRunners, runningEphemeralRunners, finishedEphemeralRunners, failedEphemeralRunners, deletingEphemeralRunners []*v1alpha1.EphemeralRunner) {
+type ephemeralRunnerState struct {
+	pending  []*v1alpha1.EphemeralRunner
+	running  []*v1alpha1.EphemeralRunner
+	finished []*v1alpha1.EphemeralRunner
+	failed   []*v1alpha1.EphemeralRunner
+	deleting []*v1alpha1.EphemeralRunner
+
+	latestPatchID int
+}
+
+func newEphemeralRunnerState(ephemeralRunnerList *v1alpha1.EphemeralRunnerList) *ephemeralRunnerState {
+	var ephemeralRunnerState ephemeralRunnerState
+
 	for i := range ephemeralRunnerList.Items {
 		r := &ephemeralRunnerList.Items[i]
+		patchID, err := strconv.Atoi(r.Annotations[AnnotationKeyPatchID])
+		if err == nil && patchID > ephemeralRunnerState.latestPatchID {
+			ephemeralRunnerState.latestPatchID = patchID
+		}
 		if !r.ObjectMeta.DeletionTimestamp.IsZero() {
-			deletingEphemeralRunners = append(deletingEphemeralRunners, r)
+			ephemeralRunnerState.deleting = append(ephemeralRunnerState.deleting, r)
 			continue
 		}
 
 		switch r.Status.Phase {
 		case corev1.PodRunning:
-			runningEphemeralRunners = append(runningEphemeralRunners, r)
+			ephemeralRunnerState.running = append(ephemeralRunnerState.running, r)
 		case corev1.PodSucceeded:
-			finishedEphemeralRunners = append(finishedEphemeralRunners, r)
+			ephemeralRunnerState.finished = append(ephemeralRunnerState.finished, r)
 		case corev1.PodFailed:
-			failedEphemeralRunners = append(failedEphemeralRunners, r)
+			ephemeralRunnerState.failed = append(ephemeralRunnerState.failed, r)
 		default:
 			// Pending or no phase should be considered as pending.
 			//
 			// If field is not set, that means that the EphemeralRunner
 			// did not yet have chance to update the Status.Phase field.
-			pendingEphemeralRunners = append(pendingEphemeralRunners, r)
+			ephemeralRunnerState.pending = append(ephemeralRunnerState.pending, r)
 		}
 	}
-	return
+	return &ephemeralRunnerState
+}
+
+func (s *ephemeralRunnerState) scaleTotal() int {
+	return len(s.pending) + len(s.running) + len(s.failed)
 }

controllers/actions.github.com/ephemeralrunnerset_controller_test.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"crypto/tls"
 	"encoding/base64"
+	"errors"
 	"fmt"
 	"net/http"
 	"net/http/httptest"
@@ -274,14 +275,17 @@ var _ = Describe("Test EphemeralRunnerSet controller", func() {
 	})
 
 	Context("When a new EphemeralRunnerSet scale up and down", func() {
-		It("It should delete finished EphemeralRunner and create new EphemeralRunner", func() {
+		It("Should scale only on patch ID change", func() {
 			created := new(actionsv1alpha1.EphemeralRunnerSet)
 			err := k8sClient.Get(ctx, client.ObjectKey{Name: ephemeralRunnerSet.Name, Namespace: ephemeralRunnerSet.Namespace}, created)
 			Expect(err).NotTo(HaveOccurred(), "failed to get EphemeralRunnerSet")
 
+			patchID := 1
+
 			// Scale up the EphemeralRunnerSet
 			updated := created.DeepCopy()
 			updated.Spec.Replicas = 5
+			updated.Spec.PatchID = patchID
 			err = k8sClient.Update(ctx, updated)
 			Expect(err).NotTo(HaveOccurred(), "failed to update EphemeralRunnerSet")
 
@@ -317,7 +321,8 @@ var _ = Describe("Test EphemeralRunnerSet controller", func() {
 					return len(runnerList.Items), nil
 				},
 				ephemeralRunnerSetTestTimeout,
-				ephemeralRunnerSetTestInterval).Should(BeEquivalentTo(5), "5 EphemeralRunner should be created")
+				ephemeralRunnerSetTestInterval,
+			).Should(BeEquivalentTo(5), "5 EphemeralRunner should be created")
 
 			// Mark one of the EphemeralRunner as finished
 			finishedRunner := runnerList.Items[4].DeepCopy()
@@ -325,7 +330,7 @@ var _ = Describe("Test EphemeralRunnerSet controller", func() {
 			err = k8sClient.Status().Patch(ctx, finishedRunner, client.MergeFrom(&runnerList.Items[4]))
 			Expect(err).NotTo(HaveOccurred(), "failed to update EphemeralRunner")
 
-			// Wait for the finished EphemeralRunner to be deleted
+			// Wait for the finished EphemeralRunner to be set to succeeded
 			Eventually(
 				func() error {
 					runnerList := new(actionsv1alpha1.EphemeralRunnerList)
@@ -335,17 +340,35 @@ var _ = Describe("Test EphemeralRunnerSet controller", func() {
 					}
 
 					for _, runner := range runnerList.Items {
-						if runner.Name == finishedRunner.Name {
+						if runner.Name != finishedRunner.Name {
-							return fmt.Errorf("EphemeralRunner is not deleted")
+							continue
 						}
+
+						if runner.Status.Phase != corev1.PodSucceeded {
+							return fmt.Errorf("EphemeralRunner is not finished")
+						}
+						// found pod succeeded
+						return nil
 					}
 
-					return nil
+					return errors.New("Finished ephemeral runner is not found")
 				},
 				ephemeralRunnerSetTestTimeout,
-				ephemeralRunnerSetTestInterval).Should(Succeed(), "Finished EphemeralRunner should be deleted")
+				ephemeralRunnerSetTestInterval,
+			).Should(Succeed(), "Finished EphemeralRunner should be deleted")
 
-			// We should still have the EphemeralRunnerSet scale up
+			// After one ephemeral runner is finished, simulate job done patch
+			patchID++
+			original := new(actionsv1alpha1.EphemeralRunnerSet)
+			err = k8sClient.Get(ctx, client.ObjectKey{Name: ephemeralRunnerSet.Name, Namespace: ephemeralRunnerSet.Namespace}, original)
+			Expect(err).NotTo(HaveOccurred(), "failed to get EphemeralRunnerSet")
+			updated = original.DeepCopy()
+			updated.Spec.PatchID = patchID
+			updated.Spec.Replicas = 4
+			err = k8sClient.Patch(ctx, updated, client.MergeFrom(original))
+			Expect(err).NotTo(HaveOccurred(), "failed to update EphemeralRunnerSet")
+
+			// Only finished ephemeral runner should be deleted
 			runnerList = new(actionsv1alpha1.EphemeralRunnerList)
 			Eventually(
 				func() (int, error) {
@@ -354,35 +377,27 @@ var _ = Describe("Test EphemeralRunnerSet controller", func() {
 						return -1, err
 					}
 
-					// Set status to simulate a configured EphemeralRunner
+					for _, runner := range runnerList.Items {
-					refetch := false
+						if runner.Status.Phase == corev1.PodSucceeded {
-					for i, runner := range runnerList.Items {
+							return -1, fmt.Errorf("Finished EphemeralRunner should be deleted")
-						if runner.Status.RunnerId == 0 {
-							updatedRunner := runner.DeepCopy()
-							updatedRunner.Status.Phase = corev1.PodRunning
-							updatedRunner.Status.RunnerId = i + 100
-							err = k8sClient.Status().Patch(ctx, updatedRunner, client.MergeFrom(&runner))
-							Expect(err).NotTo(HaveOccurred(), "failed to update EphemeralRunner")
-							refetch = true
-						}
-					}
-
-					if refetch {
-						err := k8sClient.List(ctx, runnerList, client.InNamespace(ephemeralRunnerSet.Namespace))
-						if err != nil {
-							return -1, err
 						}
 					}
 
 					return len(runnerList.Items), nil
 				},
 				ephemeralRunnerSetTestTimeout,
-				ephemeralRunnerSetTestInterval).Should(BeEquivalentTo(5), "5 EphemeralRunner should be created")
+				ephemeralRunnerSetTestInterval,
+			).Should(BeEquivalentTo(4), "4 EphemeralRunner should be created")
 
-			// Scale down the EphemeralRunnerSet
+			// Scaling down the EphemeralRunnerSet
-			updated = created.DeepCopy()
+			patchID++
+			original = new(actionsv1alpha1.EphemeralRunnerSet)
+			err = k8sClient.Get(ctx, client.ObjectKey{Name: ephemeralRunnerSet.Name, Namespace: ephemeralRunnerSet.Namespace}, original)
+			Expect(err).NotTo(HaveOccurred(), "failed to get EphemeralRunnerSet")
+			updated = original.DeepCopy()
+			updated.Spec.PatchID = patchID
 			updated.Spec.Replicas = 3
-			err = k8sClient.Patch(ctx, updated, client.MergeFrom(created))
+			err = k8sClient.Patch(ctx, updated, client.MergeFrom(original))
 			Expect(err).NotTo(HaveOccurred(), "failed to update EphemeralRunnerSet")
 
 			// Wait for the EphemeralRunnerSet to be scaled down
@@ -417,7 +432,8 @@ var _ = Describe("Test EphemeralRunnerSet controller", func() {
 					return len(runnerList.Items), nil
 				},
 				ephemeralRunnerSetTestTimeout,
-				ephemeralRunnerSetTestInterval).Should(BeEquivalentTo(3), "3 EphemeralRunner should be created")
+				ephemeralRunnerSetTestInterval,
+			).Should(BeEquivalentTo(3), "3 EphemeralRunner should be created")
 
 			// We will not scale down runner that is running jobs
 			runningRunner := runnerList.Items[0].DeepCopy()
@@ -430,10 +446,15 @@ var _ = Describe("Test EphemeralRunnerSet controller", func() {
 			err = k8sClient.Status().Patch(ctx, runningRunner, client.MergeFrom(&runnerList.Items[1]))
 			Expect(err).NotTo(HaveOccurred(), "failed to update EphemeralRunner")
 
-			// Scale down to 1
+			// Scale down to 1 while 2 are running
-			updated = created.DeepCopy()
+			patchID++
+			original = new(actionsv1alpha1.EphemeralRunnerSet)
+			err = k8sClient.Get(ctx, client.ObjectKey{Name: ephemeralRunnerSet.Name, Namespace: ephemeralRunnerSet.Namespace}, original)
+			Expect(err).NotTo(HaveOccurred(), "failed to get EphemeralRunnerSet")
+			updated = original.DeepCopy()
+			updated.Spec.PatchID = patchID
 			updated.Spec.Replicas = 1
-			err = k8sClient.Patch(ctx, updated, client.MergeFrom(created))
+			err = k8sClient.Patch(ctx, updated, client.MergeFrom(original))
 			Expect(err).NotTo(HaveOccurred(), "failed to update EphemeralRunnerSet")
 
 			// Wait for the EphemeralRunnerSet to be scaled down to 2 since we still have 2 runner running jobs
@@ -468,7 +489,8 @@ var _ = Describe("Test EphemeralRunnerSet controller", func() {
 					return len(runnerList.Items), nil
 				},
 				ephemeralRunnerSetTestTimeout,
-				ephemeralRunnerSetTestInterval).Should(BeEquivalentTo(2), "2 EphemeralRunner should be created")
+				ephemeralRunnerSetTestInterval,
+			).Should(BeEquivalentTo(2), "2 EphemeralRunner should be created")
 
 			// We will not scale down failed runner
 			failedRunner := runnerList.Items[0].DeepCopy()
@@ -476,15 +498,8 @@ var _ = Describe("Test EphemeralRunnerSet controller", func() {
 			err = k8sClient.Status().Patch(ctx, failedRunner, client.MergeFrom(&runnerList.Items[0]))
 			Expect(err).NotTo(HaveOccurred(), "failed to update EphemeralRunner")
 
-			// Scale down to 0
-			updated = created.DeepCopy()
-			updated.Spec.Replicas = 0
-			err = k8sClient.Patch(ctx, updated, client.MergeFrom(created))
-			Expect(err).NotTo(HaveOccurred(), "failed to update EphemeralRunnerSet")
-
-			// We should not scale down the EphemeralRunnerSet since we still have 1 runner running job and 1 failed runner
 			runnerList = new(actionsv1alpha1.EphemeralRunnerList)
-			Consistently(
+			Eventually(
 				func() (int, error) {
 					err := k8sClient.List(ctx, runnerList, client.InNamespace(ephemeralRunnerSet.Namespace))
 					if err != nil {
@@ -514,7 +529,8 @@ var _ = Describe("Test EphemeralRunnerSet controller", func() {
 					return len(runnerList.Items), nil
 				},
 				ephemeralRunnerSetTestTimeout,
-				ephemeralRunnerSetTestInterval).Should(BeEquivalentTo(2), "2 EphemeralRunner should be created")
+				ephemeralRunnerSetTestInterval,
+			).Should(BeEquivalentTo(2), "2 EphemeralRunner should be created")
 
 			// We will scale down to 0 when the running job is completed and the failed runner is deleted
 			runningRunner = runnerList.Items[1].DeepCopy()
@@ -525,6 +541,17 @@ var _ = Describe("Test EphemeralRunnerSet controller", func() {
 			err = k8sClient.Delete(ctx, &runnerList.Items[0])
 			Expect(err).NotTo(HaveOccurred(), "failed to delete EphemeralRunner")
 
+			// Scale down to 0 while 1 ephemeral runner is failed
+			patchID++
+			original = new(actionsv1alpha1.EphemeralRunnerSet)
+			err = k8sClient.Get(ctx, client.ObjectKey{Name: ephemeralRunnerSet.Name, Namespace: ephemeralRunnerSet.Namespace}, original)
+			Expect(err).NotTo(HaveOccurred(), "failed to get EphemeralRunnerSet")
+			updated = original.DeepCopy()
+			updated.Spec.PatchID = patchID
+			updated.Spec.Replicas = 0
+			err = k8sClient.Patch(ctx, updated, client.MergeFrom(original))
+			Expect(err).NotTo(HaveOccurred(), "failed to update EphemeralRunnerSet")
+
 			// Wait for the EphemeralRunnerSet to be scaled down to 0
 			runnerList = new(actionsv1alpha1.EphemeralRunnerList)
 			Eventually(
@@ -557,7 +584,8 @@ var _ = Describe("Test EphemeralRunnerSet controller", func() {
 					return len(runnerList.Items), nil
 				},
 				ephemeralRunnerSetTestTimeout,
-				ephemeralRunnerSetTestInterval).Should(BeEquivalentTo(0), "0 EphemeralRunner should be created")
+				ephemeralRunnerSetTestInterval,
+			).Should(BeEquivalentTo(0), "0 EphemeralRunner should be created")
 		})
 
 		It("Should update status on Ephemeral Runner state changes", func() {

controllers/actions.github.com/resourcebuilder.go

@@ -563,6 +563,7 @@ func (b *resourceBuilder) newEphemeralRunner(ephemeralRunnerSet *v1alpha1.Epheme
 	for key, val := range ephemeralRunnerSet.Annotations {
 		annotations[key] = val
 	}
+	annotations[AnnotationKeyPatchID] = strconv.Itoa(ephemeralRunnerSet.Spec.PatchID)
 	return &v1alpha1.EphemeralRunner{
 		TypeMeta: metav1.TypeMeta{},
 		ObjectMeta: metav1.ObjectMeta{