Add corresponding Machines to the worker queue when reconciling Machine Class

[rishabh-11]

How to categorize this issue?

/area control-plane
/kind enhancement
/priority 3

What would you like to be added:

In the current mcm, during machine class reconciliation, the corresponding machines are added to the reconciliation queue only if no finaliser is present on the machine class. Check out the below code for reference.

machine-controller-manager/pkg/util/provider/machinecontroller/machineclass.go

Lines 157 to 175 in 0d00e14

	if class.DeletionTimestamp == nil && len(machines) > 0 {
	// If deletionTimestamp is not set and at least one machine is referring this machineClass
	if finalizers := sets.NewString(class.Finalizers...); !finalizers.Has(MCMFinalizerName) {
	// Add machineClassFinalizer as if doesn't exist
	err = c.addMachineClassFinalizers(ctx, class)
	if err != nil {
	return err
	}
	// Enqueue all machines once finalizer is added to machineClass
	// This is to allow processing of such machines
	for _, machine := range machines {
	c.enqueueMachine(machine)
	}
	}
	return nil
	}

Instead, the machines should be added to the reconciliation queue regardless of whether the finalizer is present or not.

Why is this needed:

This above-mentioned behaviour is incorrect, as machines associated with a particular machine class should be reconciled when reconciling the corresponding machine class, regardless of whether the finalizer is present or not.

[himanshu-kun]

The issue for which the current code path was introduced #560

[himanshu-kun]

Post grooming decision

Earlier machineClass events , didn't lead to reconciliation of machines. After the above change talked abt in this issue, there was only one link created i.e. we reconcile the machines for a machineClass only when machineClass(not under deletion) didn't have a finalizer.
But now we think it would be better that we reconcile the corresponding machines for every update event of the machineClass. This is also inline with the changes we want as per #761 #635