Added Selector Generation to Job.

Added selector generation to Job's
strategy.Validate, right before validation.
Can't do in defaulting since UID is not known.

Added a validation to Job to ensure that the generated
labels and selector are correct when generation was requested.
This happens right after generation, but validation is in a better
place to return an error.

Adds "manualSelector" field to batch/v1 Job to control selector generation.
Adds same field to extensions/__internal.  Conversion between those two
is automatic.

Adds "autoSelector" field to extensions/v1beta1 Job.  Used for storing batch/v1 Jobs
    - Default for v1 is to do generation.
    - Default for v1beta1 is to not do it.
    - In both cases, unset == false == do the default thing.

Release notes:
Added batch/v1 group, which contains just Job, and which is the next
version of extensions/v1beta1 Job.

The changes from the previous version are:
- Users no longer need to ensure labels on their pod template are unique to the enclosing
  job (but may add labels as needed for categorization).
- In v1beta1, job.spec.selector was defaulted from pod labels, with the user responsible for uniqueness.
  In v1, a unique label is generated and added to the pod template, and used as the selector (other
  labels added by user stay on pod template, but need not be used by selector).
- a new field called "manualSelector" field exists to control whether the new behavior is used,
  versus a more error-prone but more flexible "manual" (not generated) seletor.  Most users
  will not need to use this field and should leave it unset.

Users who are creating extensions.Job go objects and then posting them using the go client
will see a change in the default behavior.  They need to either stop providing a selector (relying on
selector generation) or else specify "spec.manualSelector" until they are ready to do the former.

pkg/apis/extensions/validation/validation.go

@@ -379,9 +379,62 @@ func ValidateThirdPartyResourceData(obj *extensions.ThirdPartyResourceData) fiel
 	return allErrs
 }
 
+// TODO: generalize for other controller objects that will follow the same pattern, such as ReplicaSet and DaemonSet, and
+// move to new location.  Replace extensions.Job with an interface.
+//
+// ValidateGeneratedSelector validates that the generated selector on a controller object match the controller object
+// metadata, and the labels on the pod template are as generated.
+func ValidateGeneratedSelector(obj *extensions.Job) field.ErrorList {
+	allErrs := field.ErrorList{}
+	if obj.Spec.ManualSelector != nil && *obj.Spec.ManualSelector {
+		return allErrs
+	}
+
+	if obj.Spec.Selector == nil {
+		return allErrs // This case should already have been checked in caller.  No need for more errors.
+	}
+
+	// If somehow uid was unset then we would get "controller-uid=" as the selector
+	// which is bad.
+	if obj.ObjectMeta.UID == "" {
+		allErrs = append(allErrs, field.Required(field.NewPath("metadata").Child("uid"), ""))
+	}
+
+	// If somehow uid was unset then we would get "controller-uid=" as the selector
+	// which is bad.
+	if obj.ObjectMeta.UID == "" {
+		allErrs = append(allErrs, field.Required(field.NewPath("metadata").Child("uid"), ""))
+	}
+
+	// If selector generation was requested, then expected labels must be
+	// present on pod template, and much match job's uid and name.  The
+	// generated (not-manual) selectors/labels ensure no overlap with other
+	// controllers.  The manual mode allows orphaning, adoption,
+	// backward-compatibility, and experimentation with new
+	// labeling/selection schemes.  Automatic selector generation should
+	// have placed certain labels on the pod, but this could have failed if
+	// the user added coflicting labels.  Validate that the expected
+	// generated ones are there.
+
+	allErrs = append(allErrs, apivalidation.ValidateHasLabel(obj.Spec.Template.ObjectMeta, field.NewPath("spec").Child("template").Child("metadata"), "controller-uid", string(obj.UID))...)
+	allErrs = append(allErrs, apivalidation.ValidateHasLabel(obj.Spec.Template.ObjectMeta, field.NewPath("spec").Child("template").Child("metadata"), "job-name", string(obj.Name))...)
+	expectedLabels := make(map[string]string)
+	expectedLabels["controller-uid"] = string(obj.UID)
+	expectedLabels["job-name"] = string(obj.Name)
+	// Whether manually or automatically generated, the selector of the job must match the pods it will produce.
+	if selector, err := unversioned.LabelSelectorAsSelector(obj.Spec.Selector); err == nil {
+		if !selector.Matches(labels.Set(expectedLabels)) {
+			allErrs = append(allErrs, field.Invalid(field.NewPath("spec").Child("selector"), obj.Spec.Selector, "`selector` not auto-generated"))
+		}
+	}
+
+	return allErrs
+}
+
 func ValidateJob(job *extensions.Job) field.ErrorList {
 	// Jobs and rcs have the same name validation
 	allErrs := apivalidation.ValidateObjectMeta(&job.ObjectMeta, true, apivalidation.ValidateReplicationControllerName, field.NewPath("metadata"))
+	allErrs = append(allErrs, ValidateGeneratedSelector(job)...)
 	allErrs = append(allErrs, ValidateJobSpec(&job.Spec, field.NewPath("spec"))...)
 	return allErrs
 }
@@ -404,6 +457,7 @@ func ValidateJobSpec(spec *extensions.JobSpec, fldPath *field.Path) field.ErrorL
 		allErrs = append(allErrs, unversionedvalidation.ValidateLabelSelector(spec.Selector, fldPath.Child("selector"))...)
 	}
 
+	// Whether manually or automatically generated, the selector of the job must match the pods it will produce.
 	if selector, err := unversioned.LabelSelectorAsSelector(spec.Selector); err == nil {
 		labels := labels.Set(spec.Template.Labels)
 		if !selector.Matches(labels) {