From ac9c93224ee2d4d3370f1d2575f77f304524205b Mon Sep 17 00:00:00 2001
From: Jan Safranek <jsafrane@redhat.com>
Date: Wed, 30 Mar 2022 14:58:07 +0200
Subject: [PATCH] Fix translation of Azure availability zones

Some Azure regions do not have any availability zones. Nodes in such zones have
these labels, where "0" is a fault domain, not an availability zone.

  "topology.kubernetes.io/region": "westus"
  "topology.kubernetes.io/zone": "0"

Azure Disk CSI driver uses zone "" in this case:
  "topology.disk.csi.azure.com/zone": ""

Fix the CSI translation to translate the fault domain "0" to "". Any value that is just
a number and not "<region>-<number>" ("centralus-1") needs to be translated to
"" in similar fashion.
---
 .../csi-translation-lib/plugins/azure_disk.go | 33 +++++++++++++++++++
 .../plugins/azure_disk_test.go                | 17 +++++++++-
 2 files changed, 49 insertions(+), 1 deletion(-)

diff --git a/staging/src/k8s.io/csi-translation-lib/plugins/azure_disk.go b/staging/src/k8s.io/csi-translation-lib/plugins/azure_disk.go
index d86f9ef1644..73f7736e56d 100644
--- a/staging/src/k8s.io/csi-translation-lib/plugins/azure_disk.go
+++ b/staging/src/k8s.io/csi-translation-lib/plugins/azure_disk.go
@@ -45,6 +45,7 @@ var (
 	managedDiskPathRE   = regexp.MustCompile(`.*/subscriptions/(?:.*)/resourceGroups/(?:.*)/providers/Microsoft.Compute/disks/(.+)`)
 	unmanagedDiskPathRE = regexp.MustCompile(`http(?:.*)://(?:.*)/vhds/(.+)`)
 	managed             = string(v1.AzureManagedDisk)
+	unzonedCSIRegionRE  = regexp.MustCompile(`^[0-9]+$`)
 )
 
 var _ InTreePlugin = &azureDiskCSITranslator{}
@@ -86,6 +87,7 @@ func (t *azureDiskCSITranslator) TranslateInTreeStorageClassToCSI(sc *storage.St
 		}
 		sc.AllowedTopologies = newTopologies
 	}
+	sc.AllowedTopologies = t.replaceFailureDomainsToCSI(sc.AllowedTopologies)
 
 	sc.Parameters = params
 
@@ -273,3 +275,34 @@ func getDiskName(diskURI string) (string, error) {
 	}
 	return matches[1], nil
 }
+
+// Replace topology values for failure domains ("<number>") to "",
+// as it's the value that the CSI driver expects.
+func (t *azureDiskCSITranslator) replaceFailureDomainsToCSI(terms []v1.TopologySelectorTerm) []v1.TopologySelectorTerm {
+	if terms == nil {
+		return nil
+	}
+
+	newTopologies := []v1.TopologySelectorTerm{}
+	for _, term := range terms {
+		newTerm := term.DeepCopy()
+		for i := range newTerm.MatchLabelExpressions {
+			exp := &newTerm.MatchLabelExpressions[i]
+			if exp.Key == AzureDiskTopologyKey {
+				for j := range exp.Values {
+					if unzonedCSIRegionRE.Match([]byte(exp.Values[j])) {
+						// Topologies "0", "1" etc are used when in-tree topology is translated to CSI in Azure
+						// regions that don't have availability zones. E.g.:
+						//    topology.kubernetes.io/region: westus
+						//    topology.kubernetes.io/zone: "0"
+						// The CSI driver uses zone "" instead of "0" in this case.
+						//    topology.disk.csi.azure.com/zone": ""
+						exp.Values[j] = ""
+					}
+				}
+			}
+		}
+		newTopologies = append(newTopologies, *newTerm)
+	}
+	return newTopologies
+}
diff --git a/staging/src/k8s.io/csi-translation-lib/plugins/azure_disk_test.go b/staging/src/k8s.io/csi-translation-lib/plugins/azure_disk_test.go
index 4e769f9261d..73fe1d72ffa 100644
--- a/staging/src/k8s.io/csi-translation-lib/plugins/azure_disk_test.go
+++ b/staging/src/k8s.io/csi-translation-lib/plugins/azure_disk_test.go
@@ -97,7 +97,7 @@ func TestGetDiskName(t *testing.T) {
 	}
 }
 
-func TestTranslateAzureDiskInTreeStorageClassToCSI(t *testing.T) {
+func TestTranslateAzureDiskInTreeInlineVolumeToCSI(t *testing.T) {
 	sharedBlobDiskKind := v1.AzureDedicatedBlobDisk
 	translator := NewAzureDiskCSITranslator()
 
@@ -495,6 +495,21 @@ func TestTranslateInTreeStorageClassToCSI(t *testing.T) {
 			options: NewStorageClass(map[string]string{"zone": "foo"}, generateToplogySelectors(AzureDiskTopologyKey, []string{"foo"})),
 			expErr:  true,
 		},
+		{
+			name:       "topology in regions without zones",
+			options:    NewStorageClass(map[string]string{}, generateToplogySelectors(v1.LabelTopologyZone, []string{"0"})),
+			expOptions: NewStorageClass(map[string]string{}, generateToplogySelectors(AzureDiskTopologyKey, []string{""})),
+		},
+		{
+			name:       "longer topology in regions without zones",
+			options:    NewStorageClass(map[string]string{}, generateToplogySelectors(v1.LabelTopologyZone, []string{"1234"})),
+			expOptions: NewStorageClass(map[string]string{}, generateToplogySelectors(AzureDiskTopologyKey, []string{""})),
+		},
+		{
+			name:       "topology in regions with zones",
+			options:    NewStorageClass(map[string]string{}, generateToplogySelectors(v1.LabelTopologyZone, []string{"centralus-1"})),
+			expOptions: NewStorageClass(map[string]string{}, generateToplogySelectors(AzureDiskTopologyKey, []string{"centralus-1"})),
+		},
 	}
 
 	for _, tc := range tcs {