kubelet: Make service environment variables optional

pkg/apis/core/fuzzer/fuzzer.go

@@ -84,6 +84,10 @@ var Funcs = func(codecs runtimeserializer.CodecFactory) []interface{} {
 			if s.SchedulerName == "" {
 				s.SchedulerName = core.DefaultSchedulerName
 			}
+			if s.EnableServiceLinks == nil {
+				enableServiceLinks := core.DefaultEnableServiceLinks
+				s.EnableServiceLinks = &enableServiceLinks
+			}
 		},
 		func(j *core.PodPhase, c fuzz.Continue) {
 			statuses := []core.PodPhase{core.PodPending, core.PodRunning, core.PodFailed, core.PodUnknown}

pkg/apis/core/types.go

@@ -2597,8 +2597,17 @@ type PodSpec struct {
 	// This is an alpha feature and may change in the future.
 	// +optional
 	RuntimeClassName *string
+	// EnableServiceLinks indicates whether information about services should be injected into pod's
+	// environment variables, matching the syntax of Docker links.
+	// +optional
+	EnableServiceLinks *bool
 }
 
+const (
+	// The default value for enableServiceLinks attribute.
+	DefaultEnableServiceLinks = true
+)
+
 // HostAlias holds the mapping between IP and hostnames that will be injected as an entry in the
 // pod's hosts file.
 type HostAlias struct {

pkg/apis/core/v1/defaults.go

@@ -23,6 +23,7 @@ import (
 	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/apimachinery/pkg/util/intstr"
 	utilfeature "k8s.io/apiserver/pkg/util/feature"
+	"k8s.io/kubernetes/pkg/apis/core"
 	"k8s.io/kubernetes/pkg/features"
 	"k8s.io/kubernetes/pkg/util/parsers"
 	utilpointer "k8s.io/utils/pointer"
@@ -182,6 +183,10 @@ func SetDefaults_PodSpec(obj *v1.PodSpec) {
 	if obj.SchedulerName == "" {
 		obj.SchedulerName = v1.DefaultSchedulerName
 	}
+	if obj.EnableServiceLinks == nil {
+		enableServiceLinks := core.DefaultEnableServiceLinks
+		obj.EnableServiceLinks = &enableServiceLinks
+	}
 }
 func SetDefaults_Probe(obj *v1.Probe) {
 	if obj.TimeoutSeconds == 0 {

pkg/apis/core/v1/defaults_test.go

@@ -1370,3 +1370,11 @@ func TestSetDefaultHostPathVolumeSource(t *testing.T) {
 		t.Errorf("Expected v1.HostPathVolumeSource default type %v, got %v", expectedType, defaultType)
 	}
 }
+
+func TestSetDefaultEnableServiceLinks(t *testing.T) {
+	pod := &v1.Pod{}
+	output := roundTrip(t, runtime.Object(pod)).(*v1.Pod)
+	if output.Spec.EnableServiceLinks == nil || *output.Spec.EnableServiceLinks != v1.DefaultEnableServiceLinks {
+		t.Errorf("Expected enableServiceLinks value: %+v\ngot: %+v\n", v1.DefaultEnableServiceLinks, *output.Spec.EnableServiceLinks)
+	}
+}

pkg/apis/core/v1/zz_generated.conversion.go

@@ -5550,6 +5550,7 @@ func autoConvert_v1_PodSpec_To_core_PodSpec(in *v1.PodSpec, out *core.PodSpec, s
 	out.DNSConfig = (*core.PodDNSConfig)(unsafe.Pointer(in.DNSConfig))
 	out.ReadinessGates = *(*[]core.PodReadinessGate)(unsafe.Pointer(&in.ReadinessGates))
 	out.RuntimeClassName = (*string)(unsafe.Pointer(in.RuntimeClassName))
+	out.EnableServiceLinks = (*bool)(unsafe.Pointer(in.EnableServiceLinks))
 	return nil
 }
 
@@ -5616,6 +5617,7 @@ func autoConvert_core_PodSpec_To_v1_PodSpec(in *core.PodSpec, out *v1.PodSpec, s
 	out.DNSConfig = (*v1.PodDNSConfig)(unsafe.Pointer(in.DNSConfig))
 	out.ReadinessGates = *(*[]v1.PodReadinessGate)(unsafe.Pointer(&in.ReadinessGates))
 	out.RuntimeClassName = (*string)(unsafe.Pointer(in.RuntimeClassName))
+	out.EnableServiceLinks = (*bool)(unsafe.Pointer(in.EnableServiceLinks))
 	return nil
 }
 

pkg/apis/core/zz_generated.deepcopy.go

@@ -3556,6 +3556,11 @@ func (in *PodSpec) DeepCopyInto(out *PodSpec) {
 		*out = new(string)
 		**out = **in
 	}
+	if in.EnableServiceLinks != nil {
+		in, out := &in.EnableServiceLinks, &out.EnableServiceLinks
+		*out = new(bool)
+		**out = **in
+	}
 	return
 }