Function findDeletableInstance

internal/controller/replicas.go:464–501

findDeletableInstance get the Pod who is supposed to be deleted when the cluster is scaled down

(cluster *apiv1.Cluster, instances []corev1.Pod)

// findDeletableInstance get the Pod who is supposed to be deleted when the cluster is scaled down
func findDeletableInstance(cluster *apiv1.Cluster, instances []corev1.Pod) string {
	resultIdx := -1
	var lastFoundSerial int

	instancesNotRunning := cluster.Status.InstanceNames

	for idx, pod := range instances {
		if nameIndex := slices.Index(instancesNotRunning, pod.Name); nameIndex != -1 {
			instancesNotRunning = slices.Delete(instancesNotRunning, nameIndex, nameIndex+1)
		}

		// Avoid parting non ready nodes, non active nodes, or primary nodes
		if !utils.IsPodReady(pod) || !utils.IsPodActive(pod) || specs.IsPodPrimary(pod) {
			continue
		}

		// If we cannot get the node serial this is not one of our Pods
		podSerial, err := specs.GetNodeSerial(pod.ObjectMeta)
		if err != nil {
			continue
		}

		if lastFoundSerial == 0 || lastFoundSerial < podSerial {
			resultIdx = idx
			lastFoundSerial = podSerial
		}
	}

	if len(instancesNotRunning) > 0 {
		return instancesNotRunning[len(instancesNotRunning)-1]
	}

	if resultIdx == -1 {
		return ""
	}

	return instances[resultIdx].Name
}