Obsolete:ArchitecturalOverview
Revision as of 11:19, 13 July 2010 by JesseAndrews (talk)
Architectural Overview
Live Notes may be taken for this topic at: http://etherpad.openstack.org/Architecture
File:ArchitecturalOverview$overview.png
“Small” components, loosely coupled
- Queue based (currently AMQP/RabbitMQ)
- Flexible schema for datastore (currently Redis)
- LDAP (allows for integration with MS Active Directory via translucent proxy)
- Workers & Web hooks (be of the web)
- Asynchronous everything (don't block)
- Components (queue, datastore, http endpoints, ...) should scale independently and allow visibility into internal state (for the pretty charts/operations)
Development goals
- Testing & Continuous Integration
- Fakes (allows development on a laptop)
- Adaptable (goal is to make integration with existing resources at organization easier)
Queue
- Each worker/agent listens on a general topic, and a subtopic for that node. Example would be "compute" & "compute:hostname"
- Messages in the queue are currently Topic, Method, Arguments - which maps to a method in the python class for the worker
- exposed via method calls
- rpc.cast to broadcast the message and not wait for a response
- rpc.call to send a message and wait for the response
Datastore
- Currently data is stored in Redis 2.0 (RC)
- Do the work on write - make reads FAST
- maintain indexes / lists of common subsets
- use pools (SETs in redis) that are drained for IPs instead of tracking what is allocated
Delta
- Scheduler does not exist (instances are distributed via the queue to the first worker that consumes the message)
- Object store in Nova is a naive stub which would be replaced with Cloud Files in Production (a simple object store that mimics Cloud Files might be good for development)
- Tornado should be phased out for WSGI-based web framework