[Dual-stack] Fix generateAPIPodStatus() of kubelet handling Secondary IP

hostIPs order may not be be consistent. If secondary IP is before
primary one, current logic adds primary IP twice into PodIPs, which
leads to error: "may specify no more than one IP for each IP family".
In this case, the second IP shouldn't be added.

Co-authored-by: Antonio Ojea <antonio.ojea.garcia@gmail.com>

pkg/kubelet/kubelet_pods.go

@@ -1624,6 +1624,13 @@ func (kl *Kubelet) generateAPIPodStatus(pod *v1.Pod, podStatus *kubecontainer.Po
 		if err != nil {
 			klog.V(4).InfoS("Cannot get host IPs", "err", err)
 		} else {
+			if s.HostIP != "" {
+				if utilnet.IPFamilyOfString(s.HostIP) != utilnet.IPFamilyOf(hostIPs[0]) {
+					kl.recorder.Eventf(pod, v1.EventTypeWarning, "HostIPsIPFamilyMismatch",
+						"Kubelet detected an IPv%s node IP (%s), but the cloud provider selected an IPv%s node IP (%s); pass an explicit `--node-ip` to kubelet to fix this.",
+						utilnet.IPFamilyOfString(s.HostIP), s.HostIP, utilnet.IPFamilyOf(hostIPs[0]), hostIPs[0].String())
+				}
+			}
 			s.HostIP = hostIPs[0].String()
 			// HostNetwork Pods inherit the node IPs as PodIPs. They are immutable once set,
 			// other than that if the node becomes dual-stack, we add the secondary IP.
@@ -1635,7 +1642,9 @@ func (kl *Kubelet) generateAPIPodStatus(pod *v1.Pod, podStatus *kubecontainer.Po
 				}
 				// Secondary IP is not set #105320
 				if len(hostIPs) == 2 && len(s.PodIPs) == 1 {
-					s.PodIPs = append(s.PodIPs, v1.PodIP{IP: hostIPs[1].String()})
+					if utilnet.IPFamilyOfString(s.PodIPs[0].IP) != utilnet.IPFamilyOf(hostIPs[1]) {
+						s.PodIPs = append(s.PodIPs, v1.PodIP{IP: hostIPs[1].String()})
+					}
 				}
 			}
 		}

pkg/kubelet/kubelet_pods_test.go

@@ -3880,6 +3880,17 @@ func TestNodeAddressUpdatesGenerateAPIPodStatusHostNetworkPodIPs(t *testing.T) {
 				{IP: "2001:db8::2"},
 			},
 		},
+		{
+			name:    "Update secondary after new secondary address dual-stack - reverse order",
+			nodeIPs: []string{"2001:db8::2"},
+			nodeAddresses: []v1.NodeAddress{
+				{Type: v1.NodeInternalIP, Address: "10.0.0.1"},
+				{Type: v1.NodeInternalIP, Address: "2001:db8::2"},
+			},
+			expectedPodIPs: []v1.PodIP{
+				{IP: "2001:db8::2"},
+			},
+		},
 	}
 
 	for _, tc := range testcases {