Glance - image service

Glance provides discovery, registration, and delivery services for disk images.

When one boots a virtual machine (also known as an instance), it is typically required to provide a disk image. These typically contain an operating system (such as Ubuntu or Red Hat Enterprise Linux), and are best described as a snapshot of a disk's contents. Examples of disk image types include QCOW2, VMDK, VHDX, ISO, and RAW. The disk image has usually been previously created by a person or script who has gone through the initial installation procedure and has installed specific configuration files to ensure it is cloud-aware. Glance can store images in a variety of data stores, including the local filesystem or OpenStack Swift.