Add a disable subPath flag for prometheus-db volume

Documentation/api.md

@@ -627,6 +627,7 @@ StorageSpec defines the configured storage for a group Prometheus servers. If ne
 
 | Field | Description | Scheme | Required |
 | ----- | ----------- | ------ | -------- |
+| disableMountSubPath | Deprecated: subPath usage will be disabled by default in a future release, this option will become unnecessary. DisableMountSubPath allows to remove any subPath usage in volume mounts. | bool | false |
 | 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://kubernetes.io/docs/reference/generated/kubernetes-api/v1.17/#emptydirvolumesource-v1-core) | false |
 | volumeClaimTemplate | A PVC spec to be used by the Prometheus StatefulSets. | [v1.PersistentVolumeClaim](https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.17/#persistentvolumeclaim-v1-core) | false |
 

example/prometheus-operator-crd/monitoring.coreos.com_alertmanagers.yaml

@@ -2969,6 +2969,11 @@ spec:
               description: Storage is the definition of how storage will be used by
                 the Alertmanager instances.
               properties:
+                disableMountSubPath:
+                  description: 'Deprecated: subPath usage will be disabled by default
+                    in a future release, this option will become unnecessary. DisableMountSubPath
+                    allows to remove any subPath usage in volume mounts.'
+                  type: boolean
                 emptyDir:
                   description: 'EmptyDirVolumeSource to be used by the Prometheus
                     StatefulSets. If specified, used in place of any volumeClaimTemplate.

example/prometheus-operator-crd/monitoring.coreos.com_prometheuses.yaml

@@ -4276,6 +4276,11 @@ spec:
             storage:
               description: Storage spec to specify how storage shall be used.
               properties:
+                disableMountSubPath:
+                  description: 'Deprecated: subPath usage will be disabled by default
+                    in a future release, this option will become unnecessary. DisableMountSubPath
+                    allows to remove any subPath usage in volume mounts.'
+                  type: boolean
                 emptyDir:
                   description: 'EmptyDirVolumeSource to be used by the Prometheus
                     StatefulSets. If specified, used in place of any volumeClaimTemplate.

example/prometheus-operator-crd/monitoring.coreos.com_thanosrulers.yaml

@@ -3223,6 +3223,11 @@ spec:
             storage:
               description: Storage spec to specify how storage shall be used.
               properties:
+                disableMountSubPath:
+                  description: 'Deprecated: subPath usage will be disabled by default
+                    in a future release, this option will become unnecessary. DisableMountSubPath
+                    allows to remove any subPath usage in volume mounts.'
+                  type: boolean
                 emptyDir:
                   description: 'EmptyDirVolumeSource to be used by the Prometheus
                     StatefulSets. If specified, used in place of any volumeClaimTemplate.

pkg/alertmanager/statefulset.go

@@ -570,6 +570,10 @@ func subPathForStorage(s *monitoringv1.StorageSpec) string {
 		return ""
 	}
 
+	if s.DisableMountSubPath {
+		return ""
+	}
+
 	return "alertmanager-db"
 }
 

pkg/apis/monitoring/v1/types.go

@@ -375,6 +375,9 @@ type AlertingSpec struct {
 // If neither `emptyDir` nor `volumeClaimTemplate` is specified, then by default an [EmptyDir](https://kubernetes.io/docs/concepts/storage/volumes/#emptydir) will be used.
 // +k8s:openapi-gen=true
 type StorageSpec struct {
+	// Deprecated: subPath usage will be disabled by default in a future release, this option will become unnecessary.
+	// DisableMountSubPath allows to remove any subPath usage in volume mounts.
+	DisableMountSubPath bool `json:"disableMountSubPath,omitempty"`
 	// 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"`

pkg/prometheus/statefulset.go

@@ -944,5 +944,9 @@ func subPathForStorage(s *monitoringv1.StorageSpec) string {
 		return ""
 	}
 
+	if s.DisableMountSubPath {
+		return ""
+	}
+
 	return "prometheus-db"
 }