Add server name for the Machine InternalDNS

For a node to join the cluster, a CSR generated by kubelet with
the node name must be approved. The approval happens if the value
of the NodeInternalDNS entry on the Machine matches the node name.
When using legacy cloud provider the value of that node name is the
Server name. This commit ensures the nodes handled with legacy cloud
provides get approved by adding the server name to the list of Machine
addresses.

Author: MaysaMacedo

controllers/openstackmachine_controller.go

@@ -348,6 +348,14 @@ func (r *OpenStackMachineReconciler) reconcileNormal(ctx context.Context, scope
 	}
 
 	addresses := instanceNS.Addresses()
+
+	// For OpenShift and likely other systems, a node joins the cluster if the CSR generated by kubelet with the node name is approved.
+	// The approval happens if the Machine InternalDNS matches the node name. The in-tree provider used the server name for the node name.
+	// Let's add the server name as the InternalDNS to keep getting CSRs of nodes upgraded from in-tree provider approved.
+	addresses = append(addresses, corev1.NodeAddress{
+		Type:    corev1.NodeInternalDNS,
+		Address: instanceStatus.Name(),
+	})
 	openStackMachine.Status.Addresses = addresses
 
 	switch instanceStatus.State() {

test/e2e/suites/e2e/e2e_test.go

@@ -415,6 +415,12 @@ var _ = Describe("e2e tests [PR-Blocking]", func() {
 
 				// All IP addresses on all ports should be reported in Addresses
 				Expect(machine.Status.Addresses).To(ContainElements(seenAddresses))
+
+				// Expect an InternalDNS entry matching the name of the OpenStack server
+				Expect(machine.Status.Addresses).To(ContainElement(clusterv1.MachineAddress{
+					Type:    clusterv1.MachineInternalDNS,
+					Address: machine.Spec.InfrastructureRef.Name,
+				}))
 			}
 		})
 	})