Key Concepts¶

Image

A virtual machine image is a single file which contains a virtual disk that has a bootable operating system installed on it. Virtual machine images come in different formats, such as raw and qcow2.

Store

An image store is where the virtual machine images managed by Glance reside on a persistent medium. While Glance currently has support for many different stores, the most commonly deployed stores are file and swift.

file

This store refers to a directory on a local file system where the glance-registry service is running. The directory could refer to:

• locally attached storage
• a remote, shared filesystem (e.g. NFS) - see the section called “Basic Configuration of Glance Using ONTAP as a Glance Backing Store”, or
• a remote block device that has been partitioned and a filesystem created within a partition - see the section called “Basic Configuration of Glance Using E-Series as a Glance Backing Store”`

swift

This store refers to an instance of the OpenStack Object Storage service (Swift).