storagespec: add EmptyDirVolumeSource to prometheus/alertmanager statefulsets

Documentation/api.md

@@ -320,6 +320,7 @@ StorageSpec defines the configured storage for a group Prometheus servers.
 | Field | Description | Scheme | Required |
 | ----- | ----------- | ------ | -------- |
 | class | Name of the StorageClass to use when requesting storage provisioning. More info: https://kubernetes.io/docs/user-guide/persistent-volumes/#storageclasses DEPRECATED | string | true |
+| emptyDir | EmptyDirVolumeSource to be used by the Prometheus StatefulSets. If specified, used in place of any volumeClaimTemplate. More info: https://kubernetes.io/docs/concepts/storage/volumes/#emptydir | *[v1.EmptyDirVolumeSource](https://v1-6.docs.kubernetes.io/docs/api-reference/v1.6/#emptydirvolumesource-v1-core) | false |
 | selector | A label query over volumes to consider for binding. DEPRECATED | *[metav1.LabelSelector](https://v1-6.docs.kubernetes.io/docs/api-reference/v1.6/#labelselector-v1-meta) | true |
 | resources | Resources represents the minimum resources the volume should have. More info: http://kubernetes.io/docs/user-guide/persistent-volumes#resources DEPRECATED | [v1.ResourceRequirements](https://v1-6.docs.kubernetes.io/docs/api-reference/v1.6/#resourcerequirements-v1-core) | true |
 | volumeClaimTemplate | A PVC spec to be used by the Prometheus StatefulSets. | [v1.PersistentVolumeClaim](https://v1-6.docs.kubernetes.io/docs/api-reference/v1.6/#persistentvolumeclaim-v1-core) | false |

cmd/po-docgen/api.go

@@ -47,6 +47,7 @@ var (
 		"v1.LocalObjectReference":  "https://v1-6.docs.kubernetes.io/docs/api-reference/v1.6/#localobjectreference-v1-core",
 		"v1.SecretKeySelector":     "https://v1-6.docs.kubernetes.io/docs/api-reference/v1.6/#secretkeyselector-v1-core",
 		"v1.PersistentVolumeClaim": "https://v1-6.docs.kubernetes.io/docs/api-reference/v1.6/#persistentvolumeclaim-v1-core",
+		"v1.EmptyDirVolumeSource":  "https://v1-6.docs.kubernetes.io/docs/api-reference/v1.6/#emptydirvolumesource-v1-core",
 	}
 
 	selfLinks = map[string]string{}

pkg/alertmanager/statefulset.go

@@ -106,6 +106,14 @@ func makeStatefulSet(am *monitoringv1.Alertmanager, old *v1beta1.StatefulSet, co
 				EmptyDir: &v1.EmptyDirVolumeSource{},
 			},
 		})
+	} else if storageSpec.EmptyDir != nil {
+		emptyDir := storageSpec.EmptyDir
+		statefulset.Spec.Template.Spec.Volumes = append(statefulset.Spec.Template.Spec.Volumes, v1.Volume{
+			Name: volumeName(am.Name),
+			VolumeSource: v1.VolumeSource{
+				EmptyDir: emptyDir,
+			},
+		})
 	} else {
 		pvcTemplate := storageSpec.VolumeClaimTemplate
 		pvcTemplate.Name = volumeName(am.Name)

pkg/alertmanager/statefulset_test.go

@@ -145,3 +145,34 @@ func TestStatefulSetPVC(t *testing.T) {
 		t.Fatal("Error adding PVC Spec to StatefulSetSpec")
 	}
 }
+
+func TestStatefulEmptyDir(t *testing.T) {
+	labels := map[string]string{
+		"testlabel": "testlabelvalue",
+	}
+	annotations := map[string]string{
+		"testannotation": "testannotationvalue",
+	}
+
+	emptyDir := v1.EmptyDirVolumeSource{
+		Medium: v1.StorageMediumMemory,
+	}
+
+	sset, err := makeStatefulSet(&monitoringv1.Alertmanager{
+		ObjectMeta: metav1.ObjectMeta{
+			Labels:      labels,
+			Annotations: annotations,
+		},
+		Spec: monitoringv1.AlertmanagerSpec{
+			Storage: &monitoringv1.StorageSpec{
+				EmptyDir: &emptyDir,
+			},
+		},
+	}, nil, defaultTestConfig)
+
+	require.NoError(t, err)
+	ssetVolumes := sset.Spec.Template.Spec.Volumes
+	if ssetVolumes[len(ssetVolumes)-1].VolumeSource.EmptyDir != nil && !reflect.DeepEqual(emptyDir.Medium, ssetVolumes[len(ssetVolumes)-1].VolumeSource.EmptyDir.Medium) {
+		t.Fatal("Error adding EmptyDir Spec to StatefulSetSpec")
+	}
+}

pkg/client/monitoring/v1/types.go

@@ -157,6 +157,9 @@ type StorageSpec struct {
 	// info: https://kubernetes.io/docs/user-guide/persistent-volumes/#storageclasses
 	// DEPRECATED
 	Class string `json:"class"`
+	// EmptyDirVolumeSource to be used by the Prometheus StatefulSets. If specified, used in place of any volumeClaimTemplate. More
+	// info: https://kubernetes.io/docs/concepts/storage/volumes/#emptydir
+	EmptyDir *v1.EmptyDirVolumeSource `json:"emptyDir,omitempty"`
 	// A label query over volumes to consider for binding.
 	// DEPRECATED
 	Selector *metav1.LabelSelector `json:"selector"`

pkg/client/monitoring/v1/zz_generated.deepcopy.go

@@ -798,6 +798,15 @@ func (in *ServiceMonitorSpec) DeepCopy() *ServiceMonitorSpec {
 // DeepCopyInto is an autogenerated deepcopy function, copying the receiver, writing into out. in must be non-nil.
 func (in *StorageSpec) DeepCopyInto(out *StorageSpec) {
 	*out = *in
+	if in.EmptyDir != nil {
+		in, out := &in.EmptyDir, &out.EmptyDir
+		if *in == nil {
+			*out = nil
+		} else {
+			*out = new(core_v1.EmptyDirVolumeSource)
+			(*in).DeepCopyInto(*out)
+		}
+	}
 	if in.Selector != nil {
 		in, out := &in.Selector, &out.Selector
 		if *in == nil {

pkg/prometheus/statefulset.go

@@ -140,6 +140,14 @@ func makeStatefulSet(p monitoringv1.Prometheus, old *v1beta1.StatefulSet, config
 				EmptyDir: &v1.EmptyDirVolumeSource{},
 			},
 		})
+	} else if storageSpec.EmptyDir != nil {
+		emptyDir := storageSpec.EmptyDir
+		statefulset.Spec.Template.Spec.Volumes = append(statefulset.Spec.Template.Spec.Volumes, v1.Volume{
+			Name: volumeName(p.Name),
+			VolumeSource: v1.VolumeSource{
+				EmptyDir: emptyDir,
+			},
+		})
 	} else {
 		pvcTemplate := storageSpec.VolumeClaimTemplate
 		pvcTemplate.Name = volumeName(p.Name)

pkg/prometheus/statefulset_test.go

@@ -117,6 +117,37 @@ func TestStatefulSetPVC(t *testing.T) {
 
 }
 
+func TestStatefulSetEmptyDir(t *testing.T) {
+	labels := map[string]string{
+		"testlabel": "testlabelvalue",
+	}
+	annotations := map[string]string{
+		"testannotation": "testannotationvalue",
+	}
+
+	emptyDir := v1.EmptyDirVolumeSource{
+		Medium: v1.StorageMediumMemory,
+	}
+
+	sset, err := makeStatefulSet(monitoringv1.Prometheus{
+		ObjectMeta: metav1.ObjectMeta{
+			Labels:      labels,
+			Annotations: annotations,
+		},
+		Spec: monitoringv1.PrometheusSpec{
+			Storage: &monitoringv1.StorageSpec{
+				EmptyDir: &emptyDir,
+			},
+		},
+	}, nil, defaultTestConfig, []*v1.ConfigMap{})
+
+	require.NoError(t, err)
+	ssetVolumes := sset.Spec.Template.Spec.Volumes
+	if ssetVolumes[len(ssetVolumes)-1].VolumeSource.EmptyDir != nil && !reflect.DeepEqual(emptyDir.Medium, ssetVolumes[len(ssetVolumes)-1].VolumeSource.EmptyDir.Medium) {
+		t.Fatal("Error adding EmptyDir Spec to StatefulSetSpec")
+	}
+}
+
 func TestStatefulSetVolumeInitial(t *testing.T) {
 	expected := &v1beta1.StatefulSet{
 		Spec: v1beta1.StatefulSetSpec{