Scheduler

The scheduler that will be used is the one written by Kurt Vermeersch.
This scheduler uses static data about Amazon EC2 and information about a task in order to schedule it.
It is mainly suited for scheduling multiple tasks that need to be run at the same time.
An initial integration of the scheduler will not be able to use this feature though.
Some new considerations should be made :

- In the current CBAS system single tasks are supplied to be executed.
- These are then scheduled to execute with a minimal cost.
- This scheduling is done independently from the other tasks.

This is actually a basic implementation and should be reconsidered.
I would suggest a system where the master waits for a given amount of time for all the jobs that arrive and then combine them.
Even better still would be the usage of all the current tasks in the scheduling process, even those that are already running.
But this would require changes to the scheduler.
If it could take into account the time a given task is already running, the proximity to the hourly payment and the proximity to the deadline, it should be possible to temporarily halt a given task from executing because the scheduler might know about a cheaper period that is approaching.

Another remark is concerning the 2 workload models that are supported by the scheduler from Kurt.
Only the first one is supported at the moment.


First attempt to integrate the scheduler is implemented.
Some more test cases are executing, with java tests included.