1. At a first node of a cluster, the first node including a backup application, a backup coordinator, at least one application, a storage provider, a cluster service, and a cluster writer, a method for creating a snapshot of a shared volume that has application consistency to applications on more than one node of the cluster that use the shared volume, the method comprising: receiving a request, from a backup application, at a backup coordinator on a first node, the request requesting that a snapshot be created of a shared volume used by at least one application on the first node and by at least one application on at least one other node in the cluster, each of the at least one application on the first node and on the at least one other node including a writer, and wherein each of the first node and the at least one other node also includes a cluster writer and a cluster service; sending, by the backup coordinator, a freeze command to the cluster writer and each writer on the first node, the freeze command instructing the cluster writer and each writer on the first node to persist application data to the shared volume; sending, by the cluster writer on the first node, a notification of the freeze command to the cluster service on the first node; sending, by the cluster service on the first node, a notification of the freeze command to the cluster service on each of the at least one other node, the notification instructing the cluster service on each of the at least one other node to initiate a backup process of the shared volume on each of the at least one other node; waiting, by the cluster writer on the first node, for a notification from the cluster service on each of the at least one other node prior to returning from the freeze command, the notification indicating that each writer on the corresponding node has persisted corresponding application data to the shared volume; upon receiving the notification from the cluster service on each of the at least one other node, returning, by the cluster writer on the first node, from the freeze command; and upon the cluster writer on the first node returning from the freeze command, sending, by the backup coordinator, a request to the storage provider, the request causing the storage provider to create a snapshot of the shared volume, the snapshot having application consistency to each application on the first node and the at least one other node that uses the shared volume.