7e2b93acc5
This removes the majority of the nova-volume code from the codebase. It updates relevent config options to default to cinder. It updates a number of existing tests that were depending on code that was removed. A few things still need to be removed: * volume/driver.py & volume/iscsi.py These files are used by the libvirt volume driver tests. These tests should be updated to mock the relevant calls. * scheduler/simple.py & scheduler/multi.py These files should no longer be necessary so they can be removed in a subsequent patch * exception.py cleanup Once the above files are removed there are a number of unused exceptions which can be removed * database calls and database tables The database calls have not been removed and the tables have not been dropped. This can be done in a separate migration * additional config options and nova.conf.sample There may be a few extra config options that can be removed and the conf sample can be regenerated Implements bp delete-nova-volume Change-Id: I0b540e54dbabd26901a7530035a38583bb521fda
2.9 KiB
Nova System Architecture
Nova is built on a shared-nothing, messaging-based architecture. All of the major nova components can be run on multiple servers. This means that most component to component communication must go via message queue. In order to avoid blocking each component while waiting for a response, we use deferred objects, with a callback that gets triggered when a response is received.
Nova recently moved to using a sql-based central database that is shared by all components 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, nova will be moving towards multiple data stores with some kind of aggregation system.
Components
Below you will find a helpful explanation of the different components.
/- ( LDAP )
[ Auth Manager ] ---
| \- ( DB )
|
|
|
[ Web Dashboard ] -> [ api ] -- < AMQP > ------ [ network ] - ( Flat/Vlan )
| \
< HTTP > [ scheduler ] - [ compute ] - ( libvirt/xen )
| |
[ objectstore ] < - retrieves images- 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 (in the case of objectstore)
- 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.
- objectstore: http server that replicates s3 api and allows storage and retrieval of images
- scheduler: decides which host gets each vm
- network: manages ip forwarding, bridges, and vlans
- compute: manages communication with hypervisor and virtual machines.