Fix downward api for pod using host network.

pkg/kubelet/kubelet.go

@@ -1750,6 +1750,10 @@ func (kl *Kubelet) syncPod(o syncPodOptions) error {
 
 	// Generate final API pod status with pod and status manager status
 	apiPodStatus := kl.generateAPIPodStatus(pod, podStatus)
+	// The pod IP may be changed in generateAPIPodStatus if the pod is using host network. (See #24576)
+	// TODO(random-liu): After writing pod spec into container labels, check whether pod is using host network, and
+	// set pod IP to hostIP directly in runtime.GetPodStatus
+	podStatus.IP = apiPodStatus.PodIP
 
 	// Record the time it takes for the pod to become running.
 	existingStatus, ok := kl.statusManager.GetPodStatus(pod.UID)