Dual-stack support for ExternalWorkloads

charts/linkerd-crds/templates/workload/external-workload.yaml

@@ -229,16 +229,16 @@ spec:
               workloadIPs:
                 type: array
                 description: workloadIPs contains a list of IP addresses that
-                  can be used to send traffic to the workload.
+                  can be used to send traffic to the workload. This field may
+                  hold a maximum of two entries. If one entry, it can be an
+                  IPv4 or IPv6 address; if two entries it should contain one
+                  IPv4 address and one IPv6 address.
                 items:
                   type: object
                   properties:
                     ip:
                       type: string
-                # TODO: relax this in the future when ipv6 is supported
-                # an external workload (like a pod) should only
-                # support 2 interfaces
-                maxItems: 1
+                maxItems: 2
             type: object
             required:
             - meshTLS

controller/api/destination/external-workload/endpoints_reconciler.go

@@ -78,10 +78,9 @@ func (r *endpointsReconciler) reconcile(svc *corev1.Service, ews []*ewv1beta1.Ex
 	// Get the list of supported address types for the service
 	supportedAddrTypes := getSupportedAddressTypes(svc)
 	for _, slice := range existingSlices {
-		// If a slice has an address type that the slice does not support, then
+		// If a slice has an address type that the service does not support, then
 		// it should be deleted
-		_, supported := supportedAddrTypes[slice.AddressType]
-		if !supported {
+		if _, supported := supportedAddrTypes[slice.AddressType]; !supported {
 			toDelete = append(toDelete, slice)
 			continue
 		}