Why a Persistent Volume Claim in Openshift stays in 'Pending' status, showing 'exceeded quota' error Message?

Issue

• When creating a persistent volume claim ( PVC ), the request is left in pending status with an exceeded quotaerror message.
• The output of the command oc describe pvc <pvc-name> provides further details on which quota limit is reached:

$ oc get pvc
NAME           STATUS    VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS        AGE
postgresql     Bound     pvc-c5c9afef-292b-11e9-a72e-fa163e6bed00   1Gi        RWO            glusterfs-storage   3d
test-volume    Bound     pvc-5440cc68-2b9c-11e9-a72e-fa163e6bed00   1Gi        RWO            glusterfs-storage   1m
test-volume2   Pending                                                                        glusterfs-storage   18s

$ oc describe pvc test-volume2
Name:          test-volume2
Namespace:     my-test-project
StorageClass:  glusterfs-storage
Status:        Pending
Volume:
Labels:        <none>
Annotations:   volume.beta.kubernetes.io/storage-class=glusterfs-storage
               volume.beta.kubernetes.io/storage-provisioner=kubernetes.io/glusterfs
Finalizers:    []
Capacity:
Access Modes:
Events:
  Type     Reason              Age                From                         Message
  ----     ------              ----               ----                         -------
  Warning  ProvisioningFailed  2m (x27 over 14m)  persistentvolume-controller  Failed to provision volume with StorageClass "glusterfs-storage": create volume error: failed to create endpoint/service error creating service: services "glusterfs-dynamic-test-volume2" is forbidden: exceeded quota: object-counts, requested: services=1, used: services=4, limited: services=4