Fix duplicated events in kubernetes autodiscover for pods with init o…

…r ephemeral containers (elastic#22438)

(cherry picked from commit 3dd6931)

CHANGELOG.next.asciidoc

@@ -206,6 +206,7 @@ field. You can revert this change by configuring tags for the module and omittin
 - Orderly close processors when processing pipelines are not needed anymore to release their resources. {pull}16349[16349]
 - Fix memory leak and events duplication in docker autodiscover and add_docker_metadata. {pull}21851[21851]
 - Fix parsing of expired licences. {issue}21112[21112] {pull}22180[22180]
+- Fix duplicated pod events in kubernetes autodiscover for pods with init or ephemeral containers. {pull}22438[22438]
 
 *Auditbeat*
 

libbeat/autodiscover/providers/kubernetes/pod.go

@@ -266,20 +266,33 @@ func (p *pod) Stop() {
 }
 
 func (p *pod) emit(pod *kubernetes.Pod, flag string) {
+	containers, statuses := getContainersInPod(pod)
+	p.emitEvents(pod, flag, containers, statuses)
+}
+
+// getContainersInPod returns all the containers defined in a pod and their statuses.
+// It includes init and ephemeral containers.
+func getContainersInPod(pod *kubernetes.Pod) ([]kubernetes.Container, []kubernetes.PodContainerStatus) {
+	var containers []kubernetes.Container
+	var statuses []kubernetes.PodContainerStatus
+
 	// Emit events for all containers
-	p.emitEvents(pod, flag, pod.Spec.Containers, pod.Status.ContainerStatuses)
+	containers = append(containers, pod.Spec.Containers...)
+	statuses = append(statuses, pod.Status.ContainerStatuses...)
 
 	// Emit events for all initContainers
-	p.emitEvents(pod, flag, pod.Spec.InitContainers, pod.Status.InitContainerStatuses)
+	containers = append(containers, pod.Spec.InitContainers...)
+	statuses = append(statuses, pod.Status.InitContainerStatuses...)
 
 	// Emit events for all ephemeralContainers
 	// Ephemeral containers are alpha feature in k8s and this code may require some changes, if their
 	// api change in the future.
-	var mappedEphemeralsAsContainers []kubernetes.Container
 	for _, c := range pod.Spec.EphemeralContainers {
-		mappedEphemeralsAsContainers = append(mappedEphemeralsAsContainers, kubernetes.Container(c.EphemeralContainerCommon))
+		containers = append(containers, kubernetes.Container(c.EphemeralContainerCommon))
 	}
-	p.emitEvents(pod, flag, mappedEphemeralsAsContainers, pod.Status.EphemeralContainerStatuses)
+	statuses = append(statuses, pod.Status.EphemeralContainerStatuses...)
+
+	return containers, statuses
 }
 
 func (p *pod) emitEvents(pod *kubernetes.Pod, flag string, containers []kubernetes.Container,