Overview¶

The OpenStack Block Storage service provides management of persistent block storage resources. In addition to acting as secondarily attached persistent storage, you can write images into a Cinder volume for Nova to utilize as a bootable, persistent root volume for an instance. The Block Storage service was originally a component within Nova called nova-volume, but emerged as an official, independent project in the Folsom release. Cinder is conceptually similar in function to the well-known Amazon Elastic Block Storage (EBS) offering.

Cinder is typically deployed in conjunction with other OpenStack services (e.g. Compute, Object Storage, Image, etc) as part of a larger, more comprehensive cloud infrastructure. This is not an explicit requirement, as Cinder has been successfully deployed as a standalone solution for block storage provisioning and lifecycle management.

Tip

As a management service, Cinder controls the provisioning and lifecycle management of block storage volumes. It does not reside in the I/O (data) path between the hypervisor and the storage controller, as depicted in Figure 4.1 below.

Figure 4.1. Cinder and Nova Logical Architecture¶