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Adding a Method to the OpenStack API

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Psst... hey. You're reading the latest content, but it might be out of sync with code. You can read Cinder 2011.2 docs or all OpenStack docs too.

Cinder System Architecture

The Cinder Block Storage Service is intended to be ran on one or more nodes.

Cinder uses a sql-based central database that is shared by all Cinder services in the system. The amount and depth of the data fits into a sql database quite well. For small deployments this seems like an optimal solution. For larger deployments, and especially if security is a concern, cinder will be moving towards multiple data stores with some kind of aggregation system.

Components

Below you will a brief explanation of the different components.

                                                 /- ( LDAP )
                             [ Auth Manager ] ---
                                    |            \- ( DB )
                                    |
                                    |
                   cinderclient     |
                  /             \   |
[ Web Dashboard ]-               -[ api ] -- < AMQP > -- [ scheduler ] -- [ volume ] -- ( iSCSI )
                  \             /   |
                   novaclient       |
                                    |
                                    |
                                    |
                                 < REST >
  • DB: sql database for data storage. Used by all components (LINKS NOT SHOWN)
  • Web Dashboard: potential external component that talks to the api
  • api: component that receives http requests, converts commands and communicates with other components via the queue or http
  • Auth Manager: component responsible for users/projects/and roles. Can backend to DB or LDAP. This is not a separate binary, but rather a python class that is used by most components in the system.
  • scheduler: decides which host gets each volume
  • volume: manages dynamically attachable block devices.