Add a flag to control DaemonSet eviction on non-empty nodes

cluster-autoscaler/config/autoscaling_options.go

@@ -161,6 +161,8 @@ type AutoscalingOptions struct {
 	CordonNodeBeforeTerminate bool
 	// DaemonSetEvictionForEmptyNodes is whether CA will gracefully terminate DaemonSet pods from empty nodes.
 	DaemonSetEvictionForEmptyNodes bool
+	// DaemonSetEvictionForOccupiedNodes is whether CA will gracefully terminate DaemonSet pods from non-empty nodes.
+	DaemonSetEvictionForOccupiedNodes bool
 	// User agent to use for HTTP calls.
 	UserAgent string
 }

cluster-autoscaler/core/scale_down.go

@@ -1226,6 +1226,8 @@ func (sd *ScaleDown) deleteNode(node *apiv1.Node, pods []*apiv1.Pod, daemonSetPo
 
 	sd.context.Recorder.Eventf(node, apiv1.EventTypeNormal, "ScaleDown", "marked the node as toBeDeleted/unschedulable")
 
+	daemonSetPods = selectDSPodsForEviction(daemonSetPods, sd.context.DaemonSetEvictionForOccupiedNodes)
+
 	// attempt drain
 	evictionResults, err := drainNode(node, pods, daemonSetPods, sd.context.ClientSet, sd.context.Recorder, sd.context.MaxGracefulTerminationSec, MaxPodEvictionTime, EvictionRetryTime, PodEvictionHeadroom)
 	if err != nil {
@@ -1247,6 +1249,13 @@ func (sd *ScaleDown) deleteNode(node *apiv1.Node, pods []*apiv1.Pod, daemonSetPo
 	return status.NodeDeleteResult{ResultType: status.NodeDeleteOk}
 }
 
+func selectDSPodsForEviction(pods []*apiv1.Pod, shouldEvict bool) []*apiv1.Pod {
+	if shouldEvict {
+		return daemonSetPods
+	}
+	return []*apiv1.Pod{}
+}
+
 func evictPod(podToEvict *apiv1.Pod, isDaemonSetPod bool, client kube_client.Interface, recorder kube_record.EventRecorder,
 	maxGracefulTerminationSec int, retryUntil time.Time, waitBetweenRetries time.Duration) status.PodEvictionResult {
 	recorder.Eventf(podToEvict, apiv1.EventTypeNormal, "ScaleDown", "deleting pod for node scale down")

cluster-autoscaler/main.go

@@ -178,6 +178,7 @@ var (
 	clusterAPICloudConfigAuthoritative = flag.Bool("clusterapi-cloud-config-authoritative", false, "Treat the cloud-config flag authoritatively (do not fallback to using kubeconfig flag). ClusterAPI only")
 	cordonNodeBeforeTerminate          = flag.Bool("cordon-node-before-terminating", false, "Should CA cordon nodes before terminating during downscale process")
 	daemonSetEvictionForEmptyNodes     = flag.Bool("daemonset-eviction-for-empty-nodes", false, "DaemonSet pods will be gracefully terminated from empty nodes")
+	daemonSetEvictionForOccupiedNodes  = flag.Bool("daemonset-eviction-for-occupied-nodes", true, "DaemonSet pods will be gracefully terminated from non-empty nodes")
 	userAgent                          = flag.String("user-agent", "cluster-autoscaler", "User agent used for HTTP calls.")
 )
 
@@ -254,6 +255,7 @@ func createAutoscalingOptions() config.AutoscalingOptions {
 		ClusterAPICloudConfigAuthoritative: *clusterAPICloudConfigAuthoritative,
 		CordonNodeBeforeTerminate:          *cordonNodeBeforeTerminate,
 		DaemonSetEvictionForEmptyNodes:     *daemonSetEvictionForEmptyNodes,
+		DaemonSetEvictionForOccupiedNodes:  *daemonSetEvictionForOccupiedNodes,
 		UserAgent:                          *userAgent,
 	}
 }