Principle

• Minimize user operations for managing and monitoring topologies
• REST Service centralized metadata management
• Consistent UI experience

Objective

1. Make sure consistent semantics between the term application (user space) and topology (physical space only)
2. Topology should read configuration from SiteApplicationEntity#config instead of configuration file
3. Use REST Service as only entry to manage application (START/STOP/HEALTH CHECKING) and ApplicationManager to schedule the task execution and update the execution information 
4. Eagle UI should support to manage/monitor the application on site/application page
5. Single site/application may have more than one topologies (for example hdfsAuditLogMonitoring and userProfileMonitoring should have topologies running separately)

Architecture

To have a better user experience with EAGLE ui, we could provide an interface to manage a certain topology via the ui page, such as submit a topology

Schema

Application Definition Service

• Service name: TopologyDescService
• Table name: eagle_metadata
• Prefix: topology_definition

Application Execution Service 

• Service name: ApplicationExecutionService
• Table name: eagle_metadata
• Prefix: application_execution

Use cases

1. NEW
   1. create a topology definition entity
2. START
   1. click START button
   2. check the topology's current status on the nimbus host
   3. a new thread is created to execute the submitting topology task
   4. update status
3. STOP
   1. click STOP button
   2. check the topology's current status on nimbus host
   3. a new thread is created to stop the topology
   4. update status