Ovirt 代码阅读分享

1. ovirt code reading share

2. discuss content
● jboss-as
● ovirt-engine-backend
● ovirt-engine-frontend

3. jboss-as

4. ● an application server
● implementing java ee spec
○ JSP (servlet)
○ JAX-RS (rest api)
○ EJB (serve business logic, persistent, transaction)
○ 。。。
● each spec impl is modular via jboss as configuration file
----------------------------------------------------------------------------------------jboss-as

5. ● jboss as confiuration file
○ server
■ extensions
● extension （define module）
■ profile
● subsystem （module specific configuration）
■ socket-binding-group （bind interface config）
● configuration file is loaded by "jboss-modules" project
----------------------------------------------------------------------------------------jboss-as

6. ovirt 启动 jboss-as
● ./packaging/services/ovirt-engine/ovirt-engine.py start
● 启动 jboss-as: java -D… -jar jboss-modules.jar -xxx -c ovirt-engine.xml
----------------------------------------------------------------------------------------jboss-as

7. ovirt-engine-frontend

8. ● gwt rpc 框架:
------------------------------------------------------------------------ovirt-engine-frontend

9. ● ovirt's implementation:
ServiceDefTarget
GenericApiGWTServi
ceAsync
RpcService
GenericApiGWTService
GenericApiGWTServi
ceImpl
RpcServlet
GWT.create(
GenericApiGWTServi
ce.class )
------------------------------------------------------------------------ovirt-engine-frontend

10. -----------------------------------------------------------------------ovirt-engine-frontend
GenericApiGWTServiceImpl
Backend
JNDI
GenericApiGWTServiceAsync
Frontend
VdcOperationManager
gwt-rpc

11. ovirt-engine-backend

12. ovirt backend architecture
------------------------------------------------------------------------ovirt-engine-backend
Backend
（business logic）
rest api
database
vds broker
aaa
Frontend
。。。

13. ovirt backend logic start from EJB
● 寻找 javax.ejb 内的标签: @Local, @Singleton, @Startup …
● 根据 @DependsOn({ “XXX" }) 先后加载
● 加载时执行@PostConstruct标注的方法
● example:
○ Backend.java
○ InitBackendServicesOnStartupBean.java
------------------------------------------------------------------------ovirt-engine-backend

14. Backend business logic Services（EJB）
● AsyncTaskManager
● ResourceManager
● MacPoolManager
● UserDomainsCacheManagerService
● InMemoryLockManager
● ...
------------------------------------------------------------------------ovirt-engine-backend

15. AsyncTaskManager
● what is async task?
○ vdsm commands related to storage actions
○ monitoring tasks from vdsm："vdsClient -s 0 getAllTasks"
● timely check if task finished
------------------------------------------------------------------------ovirt-engine-backend

16. ResourceManager
● manage cluster
○ schedule update from each vdsm in cluster
● manage storage pool (data center)
○ schedule update from each spm in data center
------------------------------------------------------------------------ovirt-engine-backend

17. InMemoryLockManager
● entry point to acquire command’s lock
● hold all commands’s locks
------------------------------------------------------------------------ovirt-engine-backend

18. ovirt backend Command
● bll command
○ what? take care of a business logic
○ how? interact with DAO(db), backend service, vds command
● vds command
○ simple: invoke vdsm API
------------------------------------------------------------------------ovirt-engine-backend

19. bll command’s basic flow
● canDoAction
● executeCommand
● endAction (may not execute if no task)
------------------------------------------------------------------------ovirt-engine-backend

20. bll command & async task
● invoke vds command that contains async task
● get a task id and hand it to AsyncTaskManager
● endAction() is called when task is done
------------------------------------------------------------------------ovirt-engine-backend

21. bll command & monitoring
● step & job
● monitoring step & job
○ add step/job
○ end step/job
● frontend fetch from db timely
●
------------------------------------------------------------------------ovirt-engine-backend

22. end