NEG controller part - L4 RBS External LB NEG support

[mmamczur]

This PR contains changes for the NEG controller to support L4 NetLB services.
The NEG controller will be triggered for NetLBs with the presence of the new netlb V3 finalizer

Also the PortInfo had to be extended to contain the type of L4 LB since the calculators need this info in order to pick the right subset sizes. NetLBs will use larger subsets than ILB. Also this allows to differentiate a NEG syncer for ILB vs one for NetLB, when the service moves between ILB and NetLB the syncer for the old service spec will be stopped and a new one created for the changed service.

[mmamczur]

/assign @swetharepakula
/assign @sawsa307

[mmamczur]

/hold

let's not merge this before the next code freeze ends

[swetharepakula]

Though the core logic of selecting endpoints has not changed, I think we need more tests to cover this new knob.

[swetharepakula]

Can you add tests to cover the logic of switching between netlb and ilb?

[mmamczur]

this is a good point, adding a test here won't help much. To sum up
The NetLB and ILB will use the same syncing logic but with different subset sizes.
The endpoint calculators are created together with the syncer and keep 'living' in the controller.
There is no mechanism to update the running syncers. What we can do here is to treat these syncers as different. When the service is moved ILB <-> NetLB just stop the old syncer and create a new one. I added the LB type to the syncer key, this will achieve just that.
I intended to add a test for this in the controller_test, it would work but there is a problem with the fake SvcNEG indexer and client. When a SvcNEG is created the indexer doesn't know. There is code that checks if an object extsts using the indexer and then uses the client to delete

ingress-gce/pkg/neg/manager.go

Lines 457 to 475 in c6b0781

	obj, exists, err := manager.svcNegLister.GetByKey(fmt.Sprintf("%s/%s", namespace, negName))
	if err != nil {
	return fmt.Errorf("failed retrieving neg %s/%s to delete: %w", namespace, negName, err)
	}
	if !exists {
	return nil
	}
	neg := obj.(*negv1beta1.ServiceNetworkEndpointGroup)
	if neg.GetDeletionTimestamp().IsZero() {
	start := time.Now()
	err = manager.svcNegClient.NetworkingV1beta1().ServiceNetworkEndpointGroups(namespace).Delete(context.Background(), negName, metav1.DeleteOptions{})
	metrics.PublishK8sRequestCountMetrics(start, metrics.DeleteRequest, err)
	if err != nil {
	return fmt.Errorf("errored while deleting neg cr %s/%s: %w", negName, namespace, err)
	}
	manager.logger.V(2).Info("Deleted neg cr", "svcneg", klog.KRef(namespace, negName))
	}
	return nil

. Of course in this case it does not delete since it thinks the object does not exist.
Not sure how to resolve it. Maybe just e2e test that handles that case?

[swetharepakula]

can you add tests where this is true?

[mmamczur]

added a test case to verify combinations of this being turned off etc

[cezarygerard]

I have reviewed this changes in #2565

it looks good to me

please merge these as soon as we have LGMT from Swetha and Gaurav

[sawsa307]

Looks good to me, will leave the final approval to @swetharepakula

/approve

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