Add ready field to Job status

to keep a count of the pods that have the ready condition.

Also:
- Add feature gate JobReadyPods.
- Add Ready to describe.

Change-Id: Ib934730a430a8e2a2f485671e345fe2330006939

pkg/apis/batch/validation/validation_test.go

@@ -686,6 +686,21 @@ func TestValidateJobUpdateStatus(t *testing.T) {
 				},
 			},
 			update: batch.Job{
+				ObjectMeta: metav1.ObjectMeta{
+					Name:            "abc",
+					Namespace:       metav1.NamespaceDefault,
+					ResourceVersion: "1",
+				},
+				Status: batch.JobStatus{
+					Active:    2,
+					Succeeded: 3,
+					Failed:    4,
+					Ready:     pointer.Int32(1),
+				},
+			},
+		},
+		"nil ready": {
+			old: batch.Job{
 				ObjectMeta: metav1.ObjectMeta{
 					Name:            "abc",
 					Namespace:       metav1.NamespaceDefault,
@@ -693,10 +708,22 @@ func TestValidateJobUpdateStatus(t *testing.T) {
 				},
 				Status: batch.JobStatus{
 					Active:    1,
-					Succeeded: 1,
+					Succeeded: 2,
 					Failed:    3,
 				},
 			},
+			update: batch.Job{
+				ObjectMeta: metav1.ObjectMeta{
+					Name:            "abc",
+					Namespace:       metav1.NamespaceDefault,
+					ResourceVersion: "1",
+				},
+				Status: batch.JobStatus{
+					Active:    2,
+					Succeeded: 3,
+					Failed:    4,
+				},
+			},
 		},
 		"negative counts": {
 			old: batch.Job{
@@ -720,12 +747,15 @@ func TestValidateJobUpdateStatus(t *testing.T) {
 				Status: batch.JobStatus{
 					Active:    -1,
 					Succeeded: -2,
-					Failed:    3,
+					Failed:    -3,
+					Ready:     pointer.Int32(-1),
 				},
 			},
 			wantErrs: field.ErrorList{
 				{Type: field.ErrorTypeInvalid, Field: "status.active"},
 				{Type: field.ErrorTypeInvalid, Field: "status.succeeded"},
+				{Type: field.ErrorTypeInvalid, Field: "status.failed"},
+				{Type: field.ErrorTypeInvalid, Field: "status.ready"},
 			},
 		},
 		"empty and duplicated uncounted pods": {