Validate that cronjob names are less than 52 characters

pkg/apis/batch/validation/BUILD

@@ -20,6 +20,7 @@ go_library(
         "//vendor/k8s.io/apimachinery/pkg/apis/meta/v1:go_default_library",
         "//vendor/k8s.io/apimachinery/pkg/apis/meta/v1/validation:go_default_library",
         "//vendor/k8s.io/apimachinery/pkg/labels:go_default_library",
+        "//vendor/k8s.io/apimachinery/pkg/util/validation:go_default_library",
         "//vendor/k8s.io/apimachinery/pkg/util/validation/field:go_default_library",
     ],
 )

pkg/apis/batch/validation/validation.go

@@ -22,6 +22,7 @@ import (
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	unversionedvalidation "k8s.io/apimachinery/pkg/apis/meta/v1/validation"
 	"k8s.io/apimachinery/pkg/labels"
+	apimachineryvalidation "k8s.io/apimachinery/pkg/util/validation"
 	"k8s.io/apimachinery/pkg/util/validation/field"
 	"k8s.io/kubernetes/pkg/api"
 	apivalidation "k8s.io/kubernetes/pkg/api/validation"
@@ -162,6 +163,13 @@ func ValidateCronJob(scheduledJob *batch.CronJob) field.ErrorList {
 	// CronJobs and rcs have the same name validation
 	allErrs := apivalidation.ValidateObjectMeta(&scheduledJob.ObjectMeta, true, apivalidation.ValidateReplicationControllerName, field.NewPath("metadata"))
 	allErrs = append(allErrs, ValidateCronJobSpec(&scheduledJob.Spec, field.NewPath("spec"))...)
+	if len(scheduledJob.ObjectMeta.Name) > apimachineryvalidation.DNS1035LabelMaxLength-11 {
+		// The cronjob controller appends a 11-character suffix to the cronjob (`-$TIMESTAMP`) when
+		// creating a job. The job name length limit is 63 characters.
+		// Therefore cronjob names must have length <= 63-11=52. If we don't validate this here,
+		// then job creation will fail later.
+		allErrs = append(allErrs, field.Invalid(field.NewPath("metadata").Child("name"), scheduledJob.ObjectMeta.Name, "must be no more than 52 characters"))
+	}
 	return allErrs
 }
 

pkg/apis/batch/validation/validation_test.go

@@ -520,6 +520,22 @@ func TestValidateCronJob(t *testing.T) {
 				},
 			},
 		},
+		"metadata.name: must be no more than 52 characters": {
+			ObjectMeta: metav1.ObjectMeta{
+				Name:      "10000000002000000000300000000040000000005000000000123",
+				Namespace: metav1.NamespaceDefault,
+				UID:       types.UID("1a2b3c"),
+			},
+			Spec: batch.CronJobSpec{
+				Schedule:          "* * * * ?",
+				ConcurrencyPolicy: batch.AllowConcurrent,
+				JobTemplate: batch.JobTemplateSpec{
+					Spec: batch.JobSpec{
+						Template: validPodTemplateSpec,
+					},
+				},
+			},
+		},
 		"spec.jobTemplate.spec.manualSelector: Unsupported value": {
 			ObjectMeta: metav1.ObjectMeta{
 				Name:      "mycronjob",