What functionality is offered by Cinder in OpenStack?

Cinder is the block storage service in OpenStack, designed specifically to provide persistent block storage to instances. This functionality is critical for workloads that require stable storage capabilities beyond the ephemeral nature of instance storage. With Cinder, users can create and manage volume resources, which can be attached to compute instances, enabling seamless data management, backups, and application storage requirements.

Persistent block storage is vital for applications that need data after reboots, scaling, or even when the compute instances are terminated. Cinder supports various backends, allowing flexibility in how storage is provisioned, scaled, and managed.

The other options relate to different components in OpenStack: managing compute resources is the role of Nova, orchestrating application lifecycle is a function of Heat, and hosting virtual machines is also a feature provided by Nova. Cinder's role is distinct and focused on ensuring that reliable and persistent storage is consistently available for applications running across the cloud environment.