MachineSet controller deletion requests don't need to run in a WaitGroup

[vincepri]

The MachineSet controller currently uses a WaitGroup when it scales down:

cluster-api/controllers/machineset_controller.go

Lines 377 to 393 in 59a696e

	var wg sync.WaitGroup
	wg.Add(diff)
	for _, machine := range machinesToDelete {
	go func(targetMachine *clusterv1.Machine) {
	defer wg.Done()
	err := r.Client.Delete(context.Background(), targetMachine)
	if err != nil {
	logger.Error(err, "Unable to delete Machine", "machine", targetMachine.Name)
	r.recorder.Eventf(ms, corev1.EventTypeWarning, "FailedDelete", "Failed to delete machine %q: %v", targetMachine.Name, err)
	errCh <- err
	}
	logger.Info("Deleted machine", "machine", targetMachine.Name)
	r.recorder.Eventf(ms, corev1.EventTypeNormal, "SuccessfulDelete", "Deleted machine %q", targetMachine.Name)
	}(machine)
	}
	wg.Wait()
	close(errCh)

This was added around v1alpha1 timeframe because Delete at that time was blocking. Today, these Delete calls can be done sequentially because they return right away and don't have to wait for the delete to finish.

/kind cleanup
/milestone v0.3.x
/priority backlog
/help

[k8s-ci-robot]

@vincepri:
This request has been marked as needing help from a contributor.

Please ensure the request meets the requirements listed here.

If this request no longer meets these requirements, the label can be removed
by commenting with the /remove-help command.

In response to this:

The MachineSet controller currently uses a WaitGroup when it scales down:

cluster-api/controllers/machineset_controller.go

Lines 377 to 393 in 59a696e

	var wg sync.WaitGroup
	wg.Add(diff)
	for _, machine := range machinesToDelete {
	go func(targetMachine *clusterv1.Machine) {
	defer wg.Done()
	err := r.Client.Delete(context.Background(), targetMachine)
	if err != nil {
	logger.Error(err, "Unable to delete Machine", "machine", targetMachine.Name)
	r.recorder.Eventf(ms, corev1.EventTypeWarning, "FailedDelete", "Failed to delete machine %q: %v", targetMachine.Name, err)
	errCh <- err
	}
	logger.Info("Deleted machine", "machine", targetMachine.Name)
	r.recorder.Eventf(ms, corev1.EventTypeNormal, "SuccessfulDelete", "Deleted machine %q", targetMachine.Name)
	}(machine)
	}
	wg.Wait()
	close(errCh)

This was added around v1alpha1 timeframe because Delete at that time was blocking. Today, these Delete calls can be done sequentially because they return right away and don't have to wait for the delete to finish.

/kind cleanup
/milestone v0.3.x
/priority backlog
/help

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

[akhil-rane]

@vincepri Can I take this up?

[vincepri]

go for it @akhil-rane !

[akhil-rane]

/assign