pod-overhead: add Overhead to RuntimeClass internal type

Signed-off-by: Eric Ernst <eric.ernst@intel.com>

pkg/apis/node/types.go

@@ -18,6 +18,7 @@ package node
 
 import (
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/kubernetes/pkg/apis/core"
 )
 
 // +k8s:deepcopy-gen:interfaces=k8s.io/apimachinery/pkg/runtime.Object
@@ -45,6 +46,21 @@ type RuntimeClass struct {
 	// The Handler must conform to the DNS Label (RFC 1123) requirements, and is
 	// immutable.
 	Handler string
+
+	// Overhead represents the resource overhead associated with running a pod for a
+	// given RuntimeClass. For more details, see
+	// https://git.k8s.io/enhancements/keps/sig-node/20190226-pod-overhead.md
+	// This field is alpha-level as of Kubernetes v1.16, and is only honored by servers
+	// that enable the PodOverhead feature.
+	// +optional
+	Overhead *Overhead
+}
+
+// Overhead structure represents the resource overhead associated with running a pod.
+type Overhead struct {
+	//  PodFixed represents the fixed resource overhead associated with running a pod.
+	// +optional
+	PodFixed core.ResourceList
 }
 
 // +k8s:deepcopy-gen:interfaces=k8s.io/apimachinery/pkg/runtime.Object

pkg/apis/node/validation/validation.go

@@ -19,7 +19,11 @@ package validation
 import (
 	apivalidation "k8s.io/apimachinery/pkg/api/validation"
 	"k8s.io/apimachinery/pkg/util/validation/field"
+	utilfeature "k8s.io/apiserver/pkg/util/feature"
+	"k8s.io/kubernetes/pkg/apis/core"
+	corevalidation "k8s.io/kubernetes/pkg/apis/core/validation"
 	"k8s.io/kubernetes/pkg/apis/node"
+	"k8s.io/kubernetes/pkg/features"
 )
 
 // ValidateRuntimeClass validates the RuntimeClass
@@ -30,6 +34,10 @@ func ValidateRuntimeClass(rc *node.RuntimeClass) field.ErrorList {
 		allErrs = append(allErrs, field.Invalid(field.NewPath("handler"), rc.Handler, msg))
 	}
 
+	if rc.Overhead != nil && utilfeature.DefaultFeatureGate.Enabled(features.PodOverhead) {
+		allErrs = append(allErrs, validateOverhead(rc.Overhead, field.NewPath("overhead"))...)
+	}
+
 	return allErrs
 }
 
@@ -41,3 +49,8 @@ func ValidateRuntimeClassUpdate(new, old *node.RuntimeClass) field.ErrorList {
 
 	return allErrs
 }
+
+func validateOverhead(overhead *node.Overhead, fldPath *field.Path) field.ErrorList {
+	// reuse the ResourceRequirements validation logic
+	return corevalidation.ValidateResourceRequirements(&core.ResourceRequirements{Limits: overhead.PodFixed}, fldPath)
+}

pkg/apis/node/validation/validation_test.go

@@ -19,8 +19,13 @@ package validation
 import (
 	"testing"
 
+	"k8s.io/apimachinery/pkg/api/resource"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	utilfeature "k8s.io/apiserver/pkg/util/feature"
+	featuregatetesting "k8s.io/component-base/featuregate/testing"
+	"k8s.io/kubernetes/pkg/apis/core"
 	"k8s.io/kubernetes/pkg/apis/node"
+	"k8s.io/kubernetes/pkg/features"
 
 	"github.com/stretchr/testify/assert"
 )
@@ -126,3 +131,58 @@ func TestValidateRuntimeUpdate(t *testing.T) {
 		})
 	}
 }
+
+func TestValidateOverhead(t *testing.T) {
+
+	defer featuregatetesting.SetFeatureGateDuringTest(t, utilfeature.DefaultFeatureGate, features.PodOverhead, true)()
+
+	successCase := []struct {
+		Name     string
+		overhead *node.Overhead
+	}{
+		{
+			Name: "Overhead with valid cpu and memory resources",
+			overhead: &node.Overhead{
+				PodFixed: core.ResourceList{
+					core.ResourceName(core.ResourceCPU):    resource.MustParse("10"),
+					core.ResourceName(core.ResourceMemory): resource.MustParse("10G"),
+				},
+			},
+		},
+	}
+
+	for _, tc := range successCase {
+		rc := &node.RuntimeClass{
+			ObjectMeta: metav1.ObjectMeta{Name: "foo"},
+			Handler:    "bar",
+			Overhead:   tc.overhead,
+		}
+		if errs := ValidateRuntimeClass(rc); len(errs) != 0 {
+			t.Errorf("%q unexpected error: %v", tc.Name, errs)
+		}
+	}
+
+	errorCase := []struct {
+		Name     string
+		overhead *node.Overhead
+	}{
+		{
+			Name: "Invalid Resources",
+			overhead: &node.Overhead{
+				PodFixed: core.ResourceList{
+					core.ResourceName("my.org"): resource.MustParse("10m"),
+				},
+			},
+		},
+	}
+	for _, tc := range errorCase {
+		rc := &node.RuntimeClass{
+			ObjectMeta: metav1.ObjectMeta{Name: "foo"},
+			Handler:    "bar",
+			Overhead:   tc.overhead,
+		}
+		if errs := ValidateRuntimeClass(rc); len(errs) == 0 {
+			t.Errorf("%q expected error", tc.Name)
+		}
+	}
+}