Add custom pod conversion functions from pre-v1.1 mirror pods

The functions would default values added after v1.0, so that kubelet wouldn't
fail at comparing the mirror pods against their associated static pods.

This code would need to be maintained if we ever change the default value in
Pod until we drop support for v1.0 nodes.

pkg/api/v1/backward_compatibility_test.go

@@ -153,6 +153,68 @@ func TestCompatibility_v1_PodSecurityContext(t *testing.T) {
 				"spec.hostPID",
 			},
 		},
+		{
+			name: "reseting defaults for pre-v1.1 mirror pods",
+			input: `
+{
+	"kind":"Pod",
+	"apiVersion":"v1",
+	"metadata":{
+		"name":"my-pod-name",
+		"namespace":"my-pod-namespace",
+		"annotations": {
+			"kubernetes.io/config.mirror": "mirror"
+		}
+	},
+	"spec": {
+		"containers":[{
+			"name":"a",
+			"image":"my-container-image",
+			"resources": {
+				"limits": {
+					"cpu": "100m"
+				}
+			}
+		}]
+	}
+}
+`,
+			absentKeys: []string{
+				"spec.terminationGracePeriodSeconds",
+				"spec.containers[0].resources.requests",
+			},
+		},
+		{
+			name: "preserving defaults for v1.1+ mirror pods",
+			input: `
+		{
+			"kind":"Pod",
+			"apiVersion":"v1",
+			"metadata":{
+				"name":"my-pod-name",
+				"namespace":"my-pod-namespace",
+				"annotations": {
+					"kubernetes.io/config.mirror": "cbe924f710c7e26f7693d6a341bcfad0"
+				}
+			},
+			"spec": {
+				"containers":[{
+					"name":"a",
+					"image":"my-container-image",
+					"resources": {
+						"limits": {
+							"cpu": "100m"
+						}
+					}
+				}]
+			}
+		}
+		`,
+			expectedKeys: map[string]string{
+				"spec.terminationGracePeriodSeconds":    "30",
+				"spec.containers[0].resources.requests": "map[cpu:100m]",
+			},
+		},
 	}
 
 	validator := func(obj runtime.Object) fielderrors.ValidationErrorList {

pkg/api/v1/conversion.go

@@ -24,12 +24,22 @@ import (
 	"k8s.io/kubernetes/pkg/conversion"
 )
 
+const (
+	// Annotation key used to identify mirror pods.
+	mirrorAnnotationKey = "kubernetes.io/config.mirror"
+
+	// Value used to identify mirror pods from pre-v1.1 kubelet.
+	mirrorAnnotationValue_1_0 = "mirror"
+)
+
 func addConversionFuncs() {
 	// Add non-generated conversion functions
 	err := api.Scheme.AddConversionFuncs(
+		convert_api_Pod_To_v1_Pod,
 		convert_api_PodSpec_To_v1_PodSpec,
 		convert_api_ReplicationControllerSpec_To_v1_ReplicationControllerSpec,
 		convert_api_ServiceSpec_To_v1_ServiceSpec,
+		convert_v1_Pod_To_api_Pod,
 		convert_v1_PodSpec_To_api_PodSpec,
 		convert_v1_ReplicationControllerSpec_To_api_ReplicationControllerSpec,
 		convert_v1_ServiceSpec_To_api_ServiceSpec,
@@ -386,9 +396,32 @@ func convert_v1_PodSpec_To_api_PodSpec(in *PodSpec, out *api.PodSpec, s conversi
 	} else {
 		out.ImagePullSecrets = nil
 	}
+
 	return nil
 }
 
+func convert_api_Pod_To_v1_Pod(in *api.Pod, out *Pod, s conversion.Scope) error {
+	if err := autoconvert_api_Pod_To_v1_Pod(in, out, s); err != nil {
+		return err
+	}
+	// We need to reset certain fields for mirror pods from pre-v1.1 kubelet
+	// (#15960).
+	// TODO: Remove this code after we drop support for v1.0 kubelets.
+	if value, ok := in.Annotations[mirrorAnnotationKey]; ok && value == mirrorAnnotationValue_1_0 {
+		// Reset the TerminationGracePeriodSeconds.
+		out.Spec.TerminationGracePeriodSeconds = nil
+		// Reset the resource requests.
+		for i := range out.Spec.Containers {
+			out.Spec.Containers[i].Resources.Requests = nil
+		}
+	}
+	return nil
+}
+
+func convert_v1_Pod_To_api_Pod(in *Pod, out *api.Pod, s conversion.Scope) error {
+	return autoconvert_v1_Pod_To_api_Pod(in, out, s)
+}
+
 func convert_api_ServiceSpec_To_v1_ServiceSpec(in *api.ServiceSpec, out *ServiceSpec, s conversion.Scope) error {
 	if err := autoconvert_api_ServiceSpec_To_v1_ServiceSpec(in, out, s); err != nil {
 		return err

pkg/api/v1/conversion_generated.go

@@ -1887,10 +1887,6 @@ func autoconvert_api_Pod_To_v1_Pod(in *api.Pod, out *Pod, s conversion.Scope) er
 	return nil
 }
 
-func convert_api_Pod_To_v1_Pod(in *api.Pod, out *Pod, s conversion.Scope) error {
-	return autoconvert_api_Pod_To_v1_Pod(in, out, s)
-}
-
 func autoconvert_api_PodAttachOptions_To_v1_PodAttachOptions(in *api.PodAttachOptions, out *PodAttachOptions, s conversion.Scope) error {
 	if defaulting, found := s.DefaultingInterface(reflect.TypeOf(*in)); found {
 		defaulting.(func(*api.PodAttachOptions))(in)
@@ -4912,10 +4908,6 @@ func autoconvert_v1_Pod_To_api_Pod(in *Pod, out *api.Pod, s conversion.Scope) er
 	return nil
 }
 
-func convert_v1_Pod_To_api_Pod(in *Pod, out *api.Pod, s conversion.Scope) error {
-	return autoconvert_v1_Pod_To_api_Pod(in, out, s)
-}
-
 func autoconvert_v1_PodAttachOptions_To_api_PodAttachOptions(in *PodAttachOptions, out *api.PodAttachOptions, s conversion.Scope) error {
 	if defaulting, found := s.DefaultingInterface(reflect.TypeOf(*in)); found {
 		defaulting.(func(*PodAttachOptions))(in)