Launch Specific SubTask

Use case

A developer is working on a feature that is covered by one or more specific subtask. He/she would like to execute a rally task with an existing task template file (YAML or JSON) indicating exactly what subtask will be executed.

Problem description

When executing a task with a template file in Rally, all subtasks are executed without the ability to specify one or a set of subtasks the user would like to execute.

Possible solution

• Add optional flag to rally task start command to specify one or more subtasks to execute as part of that test run.