Merge pull request #12595 from smarterclayton/add_pod_status_ip

Add status.podIP as a valid downward API target

pkg/api/v1/conversion.go

@@ -44,6 +44,7 @@ func addConversionFuncs() {
 			case "metadata.name",
 				"metadata.namespace",
 				"status.phase",
+				"status.podIP",
 				"spec.nodeName":
 				return label, value, nil
 				// This is for backwards compatibility with old v1 clients which send spec.host

pkg/api/validation/validation.go

@@ -680,7 +680,7 @@ func validateEnvVarValueFrom(ev api.EnvVar) errs.ValidationErrorList {
 	return allErrs
 }
 
-var validFieldPathExpressions = util.NewStringSet("metadata.name", "metadata.namespace")
+var validFieldPathExpressions = util.NewStringSet("metadata.name", "metadata.namespace", "status.podIP")
 
 func validateObjectFieldSelector(fs *api.ObjectFieldSelector) errs.ValidationErrorList {
 	allErrs := errs.ValidationErrorList{}

pkg/api/validation/validation_test.go

@@ -667,7 +667,7 @@ func TestValidateEnv(t *testing.T) {
 					},
 				},
 			}},
-			expectedError: "[0].valueFrom.fieldRef.fieldPath: unsupported value 'status.phase', Details: supported values: metadata.name, metadata.namespace",
+			expectedError: "[0].valueFrom.fieldRef.fieldPath: unsupported value 'status.phase', Details: supported values: metadata.name, metadata.namespace, status.podIP",
 		},
 	}
 	for _, tc := range errorCases {

pkg/kubelet/kubelet.go

@@ -1051,7 +1051,10 @@ func (kl *Kubelet) podFieldSelectorRuntimeValue(fs *api.ObjectFieldSelector, pod
 	if err != nil {
 		return "", err
 	}
-
+	switch internalFieldPath {
+	case "status.podIP":
+		return pod.Status.PodIP, nil
+	}
 	return fieldpath.ExtractFieldPathAsString(pod, internalFieldPath)
 }
 

pkg/kubelet/kubelet_test.go

@@ -1187,6 +1187,15 @@ func TestMakeEnvironmentVariables(t *testing.T) {
 							},
 						},
 					},
+					{
+						Name: "POD_IP",
+						ValueFrom: &api.EnvVarSource{
+							FieldRef: &api.ObjectFieldSelector{
+								APIVersion: testapi.Version(),
+								FieldPath:  "status.podIP",
+							},
+						},
+					},
 				},
 			},
 			masterServiceNs: "nothing",
@@ -1194,6 +1203,7 @@ func TestMakeEnvironmentVariables(t *testing.T) {
 			expectedEnvs: []kubecontainer.EnvVar{
 				{Name: "POD_NAME", Value: "dapi-test-pod-name"},
 				{Name: "POD_NAMESPACE", Value: "downward-api"},
+				{Name: "POD_IP", Value: "1.2.3.4"},
 			},
 		},
 		{
@@ -1345,6 +1355,7 @@ func TestMakeEnvironmentVariables(t *testing.T) {
 				Name:      "dapi-test-pod-name",
 			},
 		}
+		testPod.Status.PodIP = "1.2.3.4"
 
 		result, err := kl.makeEnvironmentVariables(testPod, tc.container)
 		if err != nil {