Set a default priorityClassName to Mountpoint Pods and allow customizing

charts/aws-mountpoint-s3-csi-driver/templates/controller.yaml

@@ -68,5 +68,7 @@ spec:
               value: {{ .Values.image.pullPolicy }}
             - name: MOUNTPOINT_NAMESPACE
               value: {{ .Values.mountpointPod.namespace }}
+            - name: MOUNTPOINT_PRIORITY_CLASS_NAME
+              value: {{ .Values.mountpointPod.priorityClassName }}
 
 {{- end -}}

charts/aws-mountpoint-s3-csi-driver/templates/mount-s3-priority.yaml

@@ -0,0 +1,15 @@
+{{- if .Values.experimental.podMounter -}}
+
+apiVersion: scheduling.k8s.io/v1
+kind: PriorityClass
+metadata:
+  name: mount-s3-critical
+value: 1000000000
+preemptionPolicy: Never
+globalDefault: false
+description: >-
+    Default priority class for Mountpoint Pods.
+    It has the highest possible value for non-builtin PriorityClasses to ensure Mountpoint Pods get scheduled quickly and not evicted first in case of a resource pressure.
+    It will not cause other Pods to be preempted.
+
+{{- end -}}

charts/aws-mountpoint-s3-csi-driver/values.yaml

@@ -86,6 +86,7 @@ controller:
 
 mountpointPod:
   namespace: mount-s3
+  priorityClassName: mount-s3-critical
 
 nameOverride: ""
 fullnameOverride: ""

cmd/aws-s3-csi-controller/main.go

@@ -24,6 +24,7 @@ import (
 
 var mountpointNamespace = flag.String("mountpoint-namespace", os.Getenv("MOUNTPOINT_NAMESPACE"), "Namespace to spawn Mountpoint Pods in.")
 var mountpointVersion = flag.String("mountpoint-version", os.Getenv("MOUNTPOINT_VERSION"), "Version of Mountpoint within the given Mountpoint image.")
+var mountpointPriorityClassName = flag.String("mountpoint-priority-class-name", os.Getenv("MOUNTPOINT_PRIORITY_CLASS_NAME"), "Priority class name of the Mountpoint Pods.")
 var mountpointImage = flag.String("mountpoint-image", os.Getenv("MOUNTPOINT_IMAGE"), "Image of Mountpoint to use in spawned Mountpoint Pods.")
 var mountpointImagePullPolicy = flag.String("mountpoint-image-pull-policy", os.Getenv("MOUNTPOINT_IMAGE_PULL_POLICY"), "Pull policy of Mountpoint images.")
 var mountpointContainerCommand = flag.String("mountpoint-container-command", "/bin/aws-s3-csi-mounter", "Entrypoint command of the Mountpoint Pods.")
@@ -44,6 +45,7 @@ func main() {
 	err = csicontroller.NewReconciler(mgr.GetClient(), mppod.Config{
 		Namespace:         *mountpointNamespace,
 		MountpointVersion: *mountpointVersion,
+		PriorityClassName: *mountpointPriorityClassName,
 		Container: mppod.ContainerConfig{
 			Command:         *mountpointContainerCommand,
 			Image:           *mountpointImage,

pkg/podmounter/mppod/creator.go

@@ -27,6 +27,7 @@ type ContainerConfig struct {
 type Config struct {
 	Namespace         string
 	MountpointVersion string
+	PriorityClassName string
 	Container         ContainerConfig
 	CSIDriverVersion  string
 }
@@ -84,6 +85,7 @@ func (c *Creator) Create(pod *corev1.Pod, pvc *corev1.PersistentVolumeClaim) *co
 					},
 				},
 			}},
+			PriorityClassName: c.config.PriorityClassName,
 			Affinity: &corev1.Affinity{
 				NodeAffinity: &corev1.NodeAffinity{
 					// This is to making sure Mountpoint Pod gets scheduled into same node as the Workload Pod

pkg/podmounter/mppod/creator_test.go

@@ -18,6 +18,7 @@ func TestCreatingMountpointPods(t *testing.T) {
 	image := "mp-image:latest"
 	imagePullPolicy := corev1.PullAlways
 	command := "/bin/aws-s3-csi-mounter"
+	priorityClassName := "mount-s3-critical"
 
 	// Test Pod values
 	testNode := "test-node"
@@ -29,6 +30,7 @@ func TestCreatingMountpointPods(t *testing.T) {
 	creator := mppod.NewCreator(mppod.Config{
 		Namespace:         namespace,
 		MountpointVersion: mountpointVersion,
+		PriorityClassName: priorityClassName,
 		Container: mppod.ContainerConfig{
 			Image:           image,
 			ImagePullPolicy: imagePullPolicy,
@@ -60,6 +62,7 @@ func TestCreatingMountpointPods(t *testing.T) {
 		mppod.LabelCSIDriverVersion:  csiDriverVersion,
 	}, mpPod.Labels)
 
+	assert.Equals(t, priorityClassName, mpPod.Spec.PriorityClassName)
 	assert.Equals(t, corev1.RestartPolicyOnFailure, mpPod.Spec.RestartPolicy)
 	assert.Equals(t, []corev1.Volume{
 		{

tests/controller/controller_test.go

@@ -707,6 +707,7 @@ func verifyMountpointPodFor(pod *testPod, vol *testVolume, mountpointPod *testPo
 			Operator: corev1.TolerationOpExists,
 		},
 	}))
+	Expect(mountpointPod.Spec.PriorityClassName).To(Equal(mountpointPriorityClassName))
 
 	Expect(mountpointPod.Spec.Containers[0].Image).To(Equal(mountpointImage))
 	Expect(mountpointPod.Spec.Containers[0].ImagePullPolicy).To(Equal(mountpointImagePullPolicy))

tests/controller/suite_test.go

@@ -9,6 +9,7 @@ import (
 	. "github.com/onsi/ginkgo/v2"
 	. "github.com/onsi/gomega"
 	corev1 "k8s.io/api/core/v1"
+	schedulingv1 "k8s.io/api/scheduling/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/client-go/rest"
 	"k8s.io/kubectl/pkg/scheme"
@@ -32,6 +33,7 @@ const defaultContainerImage = "public.ecr.aws/docker/library/busybox:stable-musl
 // Configuration values passed for `mppod.Config` while creating a controller to use in tests.
 const mountpointNamespace = "mount-s3"
 const mountpointVersion = "1.10.0"
+const mountpointPriorityClassName = "mount-s3-critical"
 const mountpointContainerCommand = "/bin/aws-s3-csi-mounter"
 const mountpointImage = "mp-image:latest"
 const mountpointImagePullPolicy = corev1.PullNever
@@ -80,6 +82,7 @@ var _ = BeforeSuite(func() {
 	err = csicontroller.NewReconciler(k8sManager.GetClient(), mppod.Config{
 		Namespace:         mountpointNamespace,
 		MountpointVersion: mountpointVersion,
+		PriorityClassName: mountpointPriorityClassName,
 		Container: mppod.ContainerConfig{
 			Command:         mountpointContainerCommand,
 			Image:           mountpointImage,
@@ -96,6 +99,7 @@ var _ = BeforeSuite(func() {
 	}()
 
 	createMountpointNamespace()
+	createMountpointPriorityClass()
 })
 
 var _ = AfterSuite(func() {
@@ -112,3 +116,14 @@ func createMountpointNamespace() {
 	Expect(k8sClient.Create(ctx, namespace)).To(Succeed())
 	waitForObject(namespace)
 }
+
+// createMountpointPriorityClass creates priority class for Mountpoint Pods.
+func createMountpointPriorityClass() {
+	By(fmt.Sprintf("Creating priority class  %q for Mountpoint Pods", mountpointPriorityClassName))
+	priorityClass := &schedulingv1.PriorityClass{
+		ObjectMeta: metav1.ObjectMeta{Name: mountpointPriorityClassName},
+		Value:      1000000,
+	}
+	Expect(k8sClient.Create(ctx, priorityClass)).To(Succeed())
+	waitForObject(priorityClass)
+}