fix: runner pods managed by RunnerSet to not stuck in Terminating (#1420)

This is intended to fix #1369 mostly for RunnerSet-managed runner pods. It is "mostly" because this fix might work well for RunnerDeployment in cases that #1395 does not work, like in a case that the user explicitly set the runner pod restart policy to anything other than "Never".

Ref #1369

controllers/runner_controller.go

@@ -206,6 +206,24 @@ func runnerPodOrContainerIsStopped(pod *corev1.Pod) bool {
 	return stopped
 }
 
+func ephemeralRunnerContainerStatus(pod *corev1.Pod) *corev1.ContainerStatus {
+	if getRunnerEnv(pod, "RUNNER_EPHEMERAL") != "true" {
+		return nil
+	}
+
+	for _, status := range pod.Status.ContainerStatuses {
+		if status.Name != containerName {
+			continue
+		}
+
+		status := status
+
+		return &status
+	}
+
+	return nil
+}
+
 func (r *RunnerReconciler) processRunnerDeletion(runner v1alpha1.Runner, ctx context.Context, log logr.Logger, pod *corev1.Pod) (reconcile.Result, error) {
 	finalizers, removed := removeFinalizer(runner.ObjectMeta.Finalizers, finalizerName)
 

controllers/runner_graceful_stop.go

@@ -113,9 +113,27 @@ func ensureRunnerUnregistration(ctx context.Context, retryDelay time.Duration, l
 		// Happens e.g. when dind is in runner and run completes
 		log.Info("Runner pod has been stopped with a successful status.")
 	} else if pod != nil && pod.Annotations[AnnotationKeyRunnerCompletionWaitStartTimestamp] != "" {
-		log.Info("Runner pod is annotated to wait for completion")
+		ct := ephemeralRunnerContainerStatus(pod)
+		if ct == nil {
+			log.Info("Runner pod is annotated to wait for completion, and the runner container is not ephemeral")
 
 			return &ctrl.Result{RequeueAfter: retryDelay}, nil
+		}
+
+		lts := ct.LastTerminationState.Terminated
+		if lts == nil {
+			log.Info("Runner pod is annotated to wait for completion, and the runner container is not restarting")
+
+			return &ctrl.Result{RequeueAfter: retryDelay}, nil
+		}
+
+		// Prevent runner pod from stucking in Terminating.
+		// See https://github.com/actions-runner-controller/actions-runner-controller/issues/1369
+		log.Info("Deleting runner pod anyway because it has stopped prematurely. This may leave a dangling runner resource in GitHub Actions",
+			"lastState.exitCode", lts.ExitCode,
+			"lastState.message", lts.Message,
+			"pod.phase", pod.Status.Phase,
+		)
 	} else if ok, err := unregisterRunner(ctx, ghClient, enterprise, organization, repository, runner, *runnerID); err != nil {
 		if errors.Is(err, &gogithub.RateLimitError{}) {
 			// We log the underlying error when we failed calling GitHub API to list or unregisters,