Cinder is the block storage management component. Volumes can be created and attached to instances. Then they are used on the instances as any other block device would be used. On the instance, the block device can be partitioned and a filesystem can be created and mounted. Cinder also handles snapshots. Snapshots can be taken of the block volumes or of instances. Instances can also use these snapshots as a boot source.

There is an extensive collection of storage backends that can be configured as the backing store for Cinder volumes and snapshots. By default, Logical Volume Manager (LVM) is configured. GlusterFS and Ceph are two popular software-based storage solutions. There are also many plugins for hardware appliances.

In Chapter 6, Block Storage, we'll take a look at creating and attaching volumes to instances, taking snapshots, and configuring additional storage backends to Cinder.