Add priority to Kubernetes API

api/swagger-spec/v1.json

@@ -19702,6 +19702,10 @@
        "$ref": "v1.HostAlias"
       },
       "description": "HostAliases is an optional list of hosts and IPs that will be injected into the pod's hosts file if specified. This is only valid for non-hostNetwork pods."
+     },
+     "priorityName": {
+      "type": "string",
+      "description": "If specified, indicates the pod's priority. `system` is a special keyword which indicates the highest priority. Any other name must be defined in Admission Controller config or pod will be rejected. If not specified, the pod priority will be zero."
      }
     }
    },
@@ -21001,6 +21005,11 @@
      "qosClass": {
       "type": "string",
       "description": "The Quality of Service (QOS) classification assigned to the pod based on resource requirements See PodQOSClass type for available QOS classes More info: https://github.com/kubernetes/kubernetes/blob/master/docs/design/resource-qos.md"
+     },
+     "priority": {
+      "type": "integer",
+      "format": "int32",
+      "description": "The priority value which is resolved by the Admission Controller from PodSpec.PriorityName. The higher the value, the higher the priority."
      }
     }
    },

pkg/api/types.go

@@ -2213,6 +2213,20 @@ type PodSpec struct {
 	// file if specified. This is only valid for non-hostNetwork pods.
 	// +optional
 	HostAliases []HostAlias
+	// If specified, indicates the pod's priority. "SYSTEM" is a special keyword
+	// which indicates the highest priority. Any other name must be defined by
+	// creating a PriorityClass object with that name.
+	// If not specified, the pod priority will be default or zero if there is no
+	// default.
+	// +optional
+	PriorityClassName string
+	// The priority value. Various system components use this field to find the
+	// priority of the pod. When Priority Admission Controller is enabled, it
+	// prevents users from setting this field. The admission controller populates
+	// this field from PriorityClassName.
+	// The higher the value, the higher the priority.
+	// +optional
+	Priority *int32
 }
 
 // HostAlias holds the mapping between IP and hostnames that will be injected as an entry in the

pkg/api/validation/validation.go

@@ -276,6 +276,10 @@ var ValidateClusterName = genericvalidation.ValidateClusterName
 // (where it should be) and this file.
 var ValidateClassName = NameIsDNSSubdomain
 
+// ValidatePiorityClassName can be used to check whether the given priority
+// class name is valid.
+var ValidatePriorityClassName = NameIsDNSSubdomain
+
 // TODO update all references to these functions to point to the genericvalidation ones
 // NameIsDNSSubdomain is a ValidateNameFunc for names that must be a DNS subdomain.
 func NameIsDNSSubdomain(name string, prefix bool) []string {
@@ -2296,6 +2300,20 @@ func ValidatePodSpec(spec *api.PodSpec, fldPath *field.Path) field.ErrorList {
 		allErrs = append(allErrs, ValidateHostAliases(spec.HostAliases, fldPath.Child("hostAliases"))...)
 	}
 
+	if len(spec.PriorityClassName) > 0 {
+		if !utilfeature.DefaultFeatureGate.Enabled(features.PodPriority) {
+			allErrs = append(allErrs, field.Forbidden(fldPath.Child("priorityClassName"), "Pod priority is disabled by feature-gate"))
+		} else {
+			for _, msg := range ValidatePriorityClassName(spec.PriorityClassName, false) {
+				allErrs = append(allErrs, field.Invalid(fldPath.Child("priorityClassName"), spec.PriorityClassName, msg))
+			}
+		}
+	}
+
+	if spec.Priority != nil && !utilfeature.DefaultFeatureGate.Enabled(features.PodPriority) {
+		allErrs = append(allErrs, field.Forbidden(fldPath.Child("priority"), "Pod priority is disabled by feature-gate"))
+	}
+
 	return allErrs
 }
 

pkg/api/validation/validation_test.go

@@ -3631,6 +3631,24 @@ func TestValidatePodSpec(t *testing.T) {
 	minGroupID := int64(0)
 	maxGroupID := int64(2147483647)
 
+	priorityEnabled := utilfeature.DefaultFeatureGate.Enabled("PodPriority")
+	defer func() {
+		var err error
+		// restoring the old value
+		if priorityEnabled {
+			err = utilfeature.DefaultFeatureGate.Set("PodPriority=true")
+		} else {
+			err = utilfeature.DefaultFeatureGate.Set("PodPriority=false")
+		}
+		if err != nil {
+			t.Errorf("Failed to restore feature gate for PodPriority: %v", err)
+		}
+	}()
+	err := utilfeature.DefaultFeatureGate.Set("PodPriority=true")
+	if err != nil {
+		t.Errorf("Failed to enable feature gate for PodPriority: %v", err)
+		return
+	}
 	successCases := []api.PodSpec{
 		{ // Populate basic fields, leave defaults for most.
 			Volumes:       []api.Volume{{Name: "vol", VolumeSource: api.VolumeSource{EmptyDir: &api.EmptyDirVolumeSource{}}}},
@@ -3739,6 +3757,13 @@ func TestValidatePodSpec(t *testing.T) {
 			RestartPolicy: api.RestartPolicyAlways,
 			DNSPolicy:     api.DNSClusterFirst,
 		},
+		{ // Populate PriorityClassName.
+			Volumes:           []api.Volume{{Name: "vol", VolumeSource: api.VolumeSource{EmptyDir: &api.EmptyDirVolumeSource{}}}},
+			Containers:        []api.Container{{Name: "ctr", Image: "image", ImagePullPolicy: "IfNotPresent", TerminationMessagePolicy: "File"}},
+			RestartPolicy:     api.RestartPolicyAlways,
+			DNSPolicy:         api.DNSClusterFirst,
+			PriorityClassName: "valid-name",
+		},
 	}
 	for i := range successCases {
 		if errs := ValidatePodSpec(&successCases[i], field.NewPath("field")); len(errs) != 0 {
@@ -3909,12 +3934,47 @@ func TestValidatePodSpec(t *testing.T) {
 			RestartPolicy: api.RestartPolicyAlways,
 			DNSPolicy:     api.DNSClusterFirst,
 		},
+		"bad PriorityClassName": {
+			Volumes:           []api.Volume{{Name: "vol", VolumeSource: api.VolumeSource{EmptyDir: &api.EmptyDirVolumeSource{}}}},
+			Containers:        []api.Container{{Name: "ctr", Image: "image", ImagePullPolicy: "IfNotPresent", TerminationMessagePolicy: "File"}},
+			RestartPolicy:     api.RestartPolicyAlways,
+			DNSPolicy:         api.DNSClusterFirst,
+			PriorityClassName: "InvalidName",
+		},
 	}
 	for k, v := range failureCases {
 		if errs := ValidatePodSpec(&v, field.NewPath("field")); len(errs) == 0 {
 			t.Errorf("expected failure for %q", k)
 		}
 	}
+
+	err = utilfeature.DefaultFeatureGate.Set("PodPriority=false")
+	if err != nil {
+		t.Errorf("Failed to disable feature gate for PodPriority: %v", err)
+		return
+	}
+	priority := int32(100)
+	featuregatedCases := map[string]api.PodSpec{
+		"set PriorityClassName": {
+			Volumes:           []api.Volume{{Name: "vol", VolumeSource: api.VolumeSource{EmptyDir: &api.EmptyDirVolumeSource{}}}},
+			Containers:        []api.Container{{Name: "ctr", Image: "image", ImagePullPolicy: "IfNotPresent", TerminationMessagePolicy: "File"}},
+			RestartPolicy:     api.RestartPolicyAlways,
+			DNSPolicy:         api.DNSClusterFirst,
+			PriorityClassName: "valid-name",
+		},
+		"set Priority": {
+			Volumes:       []api.Volume{{Name: "vol", VolumeSource: api.VolumeSource{EmptyDir: &api.EmptyDirVolumeSource{}}}},
+			Containers:    []api.Container{{Name: "ctr", Image: "image", ImagePullPolicy: "IfNotPresent", TerminationMessagePolicy: "File"}},
+			RestartPolicy: api.RestartPolicyAlways,
+			DNSPolicy:     api.DNSClusterFirst,
+			Priority:      &priority,
+		},
+	}
+	for k, v := range featuregatedCases {
+		if errs := ValidatePodSpec(&v, field.NewPath("field")); len(errs) == 0 {
+			t.Errorf("expected failure due to gated feature: %q", k)
+		}
+	}
 }
 
 func extendPodSpecwithTolerations(in api.PodSpec, tolerations []api.Toleration) api.PodSpec {
@@ -5781,6 +5841,50 @@ func TestValidatePodUpdate(t *testing.T) {
 			"metadata.annotations[kubernetes.io/config.mirror]",
 			"changed mirror pod annotation",
 		},
+		{
+			api.Pod{
+				ObjectMeta: metav1.ObjectMeta{
+					Name: "foo",
+				},
+				Spec: api.PodSpec{
+					NodeName:          "node1",
+					PriorityClassName: "bar-priority",
+				},
+			},
+			api.Pod{
+				ObjectMeta: metav1.ObjectMeta{
+					Name: "foo",
+				},
+				Spec: api.PodSpec{
+					NodeName:          "node1",
+					PriorityClassName: "foo-priority",
+				},
+			},
+			"spec: Forbidden: pod updates",
+			"changed priority class name",
+		},
+		{
+			api.Pod{
+				ObjectMeta: metav1.ObjectMeta{
+					Name: "foo",
+				},
+				Spec: api.PodSpec{
+					NodeName:          "node1",
+					PriorityClassName: "",
+				},
+			},
+			api.Pod{
+				ObjectMeta: metav1.ObjectMeta{
+					Name: "foo",
+				},
+				Spec: api.PodSpec{
+					NodeName:          "node1",
+					PriorityClassName: "foo-priority",
+				},
+			},
+			"spec: Forbidden: pod updates",
+			"removed priority class name",
+		},
 	}
 
 	for _, test := range tests {

pkg/features/kube_features.go

@@ -114,6 +114,12 @@ const (
 	//
 	// Allows running a "debug container" in a pod namespaces to troubleshoot a running pod.
 	DebugContainers utilfeature.Feature = "DebugContainers"
+
+	// owner: @bsalamat
+	// alpha: v1.8
+	//
+	// Add priority to pods. Priority affects scheduling and preemption of pods.
+	PodPriority utilfeature.Feature = "PodPriority"
 )
 
 func init() {
@@ -137,6 +143,7 @@ var defaultKubernetesFeatureGates = map[utilfeature.Feature]utilfeature.FeatureS
 	PersistentLocalVolumes:                      {Default: false, PreRelease: utilfeature.Alpha},
 	LocalStorageCapacityIsolation:               {Default: false, PreRelease: utilfeature.Alpha},
 	DebugContainers:                             {Default: false, PreRelease: utilfeature.Alpha},
+	PodPriority:                                 {Default: false, PreRelease: utilfeature.Alpha},
 
 	// inherited features from generic apiserver, relisted here to get a conflict if it is changed
 	// unintentionally on either side:

staging/src/k8s.io/api/core/v1/types.go

@@ -2520,6 +2520,20 @@ type PodSpec struct {
 	// +patchMergeKey=ip
 	// +patchStrategy=merge
 	HostAliases []HostAlias `json:"hostAliases,omitempty" patchStrategy:"merge" patchMergeKey:"ip" protobuf:"bytes,23,rep,name=hostAliases"`
+	// If specified, indicates the pod's priority. "SYSTEM" is a special keyword
+	// which indicates the highest priority. Any other name must be defined by
+	// creating a PriorityClass object with that name.
+	// If not specified, the pod priority will be default or zero if there is no
+	// default.
+	// +optional
+	PriorityClassName string `json:"priorityClassName,omitempty" protobuf:"bytes,24,opt,name=priorityClassName"`
+	// The priority value. Various system components use this field to find the
+	// priority of the pod. When Priority Admission Controller is enabled, it
+	// prevents users from setting this field. The admission controller populates
+	// this field from PriorityClassName.
+	// The higher the value, the higher the priority.
+	// +optional
+	Priority *int32 `json:"priority,omitempty" protobuf:"bytes,25,opt,name=priority"`
 }
 
 // HostAlias holds the mapping between IP and hostnames that will be injected as an entry in the