Add ability to discover the name of the AZ the Kubernetes node is in …

…and use that when mounting the EFS filesystem (if requested via 'discoverAzName')

pkg/driver/controller.go

@@ -43,6 +43,7 @@ const (
 	DefaultGidMax         = DefaultGidMin + cloud.AccessPointPerFsLimit
 	DefaultTagKey         = "efs.csi.aws.com/cluster"
 	DefaultTagValue       = "true"
+	DiscoverAzName        = "discoverAzName"
 	DirectoryPerms        = "directoryPerms"
 	EnsureUniqueDirectory = "ensureUniqueDirectory"
 	FsId                  = "fileSystemId"
@@ -129,6 +130,7 @@ func (d *Driver) CreateVolume(ctx context.Context, req *csi.CreateVolumeRequest)
 		roleArn                string
 		uid                    int64
 		crossAccountDNSEnabled bool
+		discoverAzNameEnabled  bool
 	)
 
 	//Parse parameters
@@ -143,6 +145,13 @@ func (d *Driver) CreateVolume(ctx context.Context, req *csi.CreateVolumeRequest)
 		return nil, status.Errorf(codes.InvalidArgument, "Missing %v parameter", ProvisioningMode)
 	}
 
+	if value, ok := volumeParams[DiscoverAzName]; ok {
+		discoverAzNameEnabled, err = strconv.ParseBool(value)
+		if err != nil {
+			return nil, status.Errorf(codes.InvalidArgument, "Failed to parse invalid %v: %v", DiscoverAzName, err)
+		}
+	}
+
 	// Create tags
 	tags := map[string]string{
 		DefaultTagKey: DefaultTagValue,
@@ -348,6 +357,10 @@ func (d *Driver) CreateVolume(ctx context.Context, req *csi.CreateVolumeRequest)
 		}
 	}
 
+	if discoverAzNameEnabled {
+		volContext[DiscoverAzName] = strconv.FormatBool(true)
+	}
+
 	return &csi.CreateVolumeResponse{
 		Volume: &csi.Volume{
 			CapacityBytes: volSize,

pkg/driver/node.go

@@ -106,6 +106,15 @@ func (d *Driver) NodePublishVolume(ctx context.Context, req *csi.NodePublishVolu
 			if err != nil {
 				return nil, status.Error(codes.InvalidArgument, fmt.Sprintf("Volume context property %q must be a boolean value: %v", k, err))
 			}
+		case strings.ToLower(DiscoverAzName):
+			discoverAzNameEnabled, err := strconv.ParseBool(v)
+			if err != nil {
+				return nil, status.Error(codes.InvalidArgument, fmt.Sprintf("Volume context property %q must be a boolean value: %v", k, err))
+			}
+			if discoverAzNameEnabled {
+				az := d.cloud.GetMetadata().GetAvailabilityZone()
+				mountOptions = append(mountOptions, "az="+az)
+			}
 		default:
 			return nil, status.Errorf(codes.InvalidArgument, "Volume context property %s not supported.", k)
 		}