Skip node cidr mask size check for cloud allocation

[grayluck]

What this PR does / why we need it:
For IPAM: Do not check if maskSize per node (flag --node-cidr-mask-size) is smaller or equals to cluster cidr (--cluster-cidr), if the secondary ranges are allocated by the cloud.

When allocatorType == CloudAllocatorType, nodeCIDRMaskSize is actually not used in creating CIDR range allocator. See:

kubernetes/pkg/controller/nodeipam/ipam/cidr_allocator.go

Lines 96 to 111 in 95ab206

	// New creates a new CIDR range allocator.
	func New(kubeClient clientset.Interface, cloud cloudprovider.Interface, nodeInformer informers.NodeInformer, allocatorType CIDRAllocatorType, clusterCIDR, serviceCIDR *net.IPNet, nodeCIDRMaskSize int) (CIDRAllocator, error) {
	nodeList, err := listNodes(kubeClient)
	if err != nil {
	return nil, err
	}
	switch allocatorType {
	case RangeAllocatorType:
	return NewCIDRRangeAllocator(kubeClient, nodeInformer, clusterCIDR, serviceCIDR, nodeCIDRMaskSize, nodeList)
	case CloudAllocatorType:
	return NewCloudCIDRAllocator(kubeClient, cloud, nodeInformer)
	default:
	return nil, fmt.Errorf("Invalid CIDR allocator type: %v", allocatorType)
	}
	}

This check is impeding nodepools from having different pod cidr sizes.

Special notes for your reviewer:

Release note:

NONE

[grayluck]

/assign @bowei

[grayluck]

/priority important-soon

[grayluck]

Tested. We can now create ip alias clusters with pod cidr range smaller than /24.
/sig network

[grayluck]

/kind bug

[bowei]

It's clearer reading the code to do this:

if allocatorType != ipam.CloudAllocatorType {
  // Note: CloudAllocatorType does not rely on clusterCIDR or nodeCIDRMaskSize for allocation.
  if maskSize, _ := mask.Size(); maskSize > nodeCIDRMaskSize {
    ... 
  }
}

[grayluck]

Updated. Thanks

[bowei]

I don't see your updates? Can you put the comment at least.

[grayluck]

My bad. Please take another look. Thx.

[bowei]

/ok-to-test

[grayluck]

/retest

[bowei]

/ok-to-test
/lgtm
/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: bowei, grayluck

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• pkg/controller/nodeipam/OWNERS [bowei]

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[grayluck]

Thanks for review, Bowei!

[grayluck]

/test pull-kubernetes-kubemark-e2e-gce-big