Chapter 6. OpenStack Block Storage Installation

⁠Chapter 6. OpenStack Block Storage Installation

⁠6.1. Block Storage Service Overview

The Block Storage (or volume) service provides persistent block storage management for virtual hard drives. Block Storage allows the user to create and delete block devices, and to manage the attachment of block devices to servers. The actual attachment and detachment of devices is handled through integration with the Compute service. Both regions and zones can be used to handle distributed block storage hosts (for details, see the Section 4.1, “Object Storage Service Overview”).

Block storage is appropriate for performance-sensitive scenarios such as database storage, expandable file systems, or providing a server with access to raw block-level storage. Additionally, snapshots can be taken to either restore data or to create new block storage volumes (snapshots are dependent upon driver support).

Basic operations include:

Create, list, and delete volumes.
Create, list, and delete snapshots.
Attach and detach volumes to running virtual machines.

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Table 6.1. Block Storage Service components

Component	Description
openstack-cinder-volume	Carves out storage for virtual machines on demand. A number of drivers are included for interaction with storage providers.
openstack-cinder-api	Responds to and handles requests, and places them in the message queue.
openstack-cinder-backup	Provides the ability to back up a Block Storage volume to an external storage repository.
openstack-cinder-scheduler	Assigns tasks to the queue and determines the provisioning volume server.
Database	Provides state information.
RabbitMQ server (`rabbitmq-server`)	Provides the AMQP message queue. This server (also used by Block Storage) handles the OpenStack transaction management, including queuing, distribution, security, management, clustering, and federation. Messaging becomes especially important when an OpenStack deployment is scaled and its services are running on multiple machines.