The OpenStack Image Service (Glance) provides discovery, registration and delivery services for disk and server images. The ability to copy or snapshot a server image and immediately store it away is a powerful capability of the OpenStack cloud operating system. Stored images can be used as a template to get new servers up and running quickly and more consistently if you are provisioning multiple servers than installing a server operating system and individually configuring additional services. It can also be used to store and catalog an unlimited number of backups.
Glance can store disk and server images in a variety of back-ends (called stores). The Glance API provides a standard REST interface for querying information about disk images and lets clients stream the images to new servers. A multiformat image registry allowing uploads of private and public images in a variety of formats.