Modeling a Self-Recoverable Grid-Based Task Scheduler

Matheus Costa LeiteOrientador: Arndt von Staa, Carlos Lucena

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Agent Network (Grid)

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Adding a Task

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= Task

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Task Structure

Task

- id- current replication level- max replication level- description- due date

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Task Handling

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I am too busy to accept this task. Maybe my right buddy can help me.

I´ll handle this task, but I´ll also send to my right buddy just in case I die.

Incremented replication

level

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Task Execution: Global View

HashBase

EntriesBase

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Task Execution: Global View

HashBase

EntriesBase

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= Here are some results from task id = 5

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Fault Tolerance

• An important issue when building a grid is what to do if a node fail.

• In order to be effective the grid must implement some sort of

fault tolerance mechanism.

• In our approach the network is a self-healing structure. When

a node dies, new links are formed to substitute the old ones.

• When a node comes back, the original configuration is

restored.

George, S; Evans, D; Marquette, S. A Biological Programming Model for Self-Healing

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Fault Tolerance: Hello Messages

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= Hello from (0, 2)

(2, 2) is alive, so I won´t remove it

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Fault Tolerance: Agent Death

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I haven´t heard from (1, 1) for a while. It

must be dead.

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Fault Tolerance: Fixing the Network

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= to the right neighbor of (1, 1). Please add me as yours left

neighbor

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Fault Tolerance: Fixing the Network

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Fault Tolerance: Restoring a Dead Agent

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Fault Tolerance: Restoring a Dead Agent

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Agent Structure

• Internally the agent is structured as a set of interconnected components:

– Worker

– Buddy Handler

– Replica Handler

– Router

– Neighbor Map

– NET

• Each component receives and sends tasks through the router

to accomplish various goals.

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References

• Magalhães, J.; Lucena, C., 2003. Using an Agent-Based Framework and Separation of Concerns for the Generation of Document Classification Tools. In AAAI Spring Symposium/AMKM-Agent Mediated Knowledge Management (to appear LNCS – Springer).

• Wang, Liu - Dynamics of Agent-based Load-Balancing

on Grids

• Fedoruk, A.; Deters, R. Using Agent Replication to

Enhance Reliability and Availability of Multi-Agent

Systems

• George, S; Evans, D; Marquette, S. A Biological

Programming Model for Self-Healing