The document discusses the application of federated HPC clouds in radiation therapy, focusing on virtual cluster architectures and experimental results from a project funded by the EU's FP7 program. It addresses challenges related to resource sharing, application performance variability, and fault tolerance in cloud environments, proposing an autonomous virtual cluster architecture to enhance performance and reduce costs. The findings indicate that distributed virtual clusters can accelerate HTC applications while maintaining high quality of service through elasticity and monitoring mechanisms.

1. Federated HPC Clouds applied to
Radiation Therapy
A. Gómez, L.M. Carril, R. Valin,
J.C. Mouriño, C. Cotelo
ISC Cloud‘13, Heidelberg (Germany)
Sep. 23-24th, 2013

2. Overview
Context.
Virtual Cluster Architecture.
Experiments on BonFIRE.
Conclusions.
The research leading to these results has received funding from the European Commision's
Seventh Framework Programme (FP7/2007-2013) under grant agreement number 257386

3. Context: eIMRT service
CTs Treatment
Results
Results
TPS
 Second calculation
 Personalized: One patient, one treatment

4. eIMRT architecture
IaaSSaaS
Workflow based
on Monte Carlo
simulations

5. eIMRT Workflow
eIMRT code: Prepares inputs
for BEAMnrc MC. Seconds in
master computer
BEAMnrc MC simulations.
Independent jobs on CEs.
eIMRT code: collects outputs and
prepares inputs for DOSXYZnrc
Seconds in master computer
eIMRT code: collects outputs
and generates final output..
Seconds in master computer
DOSXYZnrc MC simulations.
Independent jobs on CEs.

6. SaaS issues
Local cluster:
– Could not be enough with many clients.
– Interferences between customer’s requests.
– Shared resources: Time-to-solution not guaranteed.
Grid:
– Interferences between clients.
– Shared resources: Time-to-solution not guaranteed.
Cloud:
– One treatment, one virtual cluster.
– No interferences between treatments, customers.
– But, How to guarantee the time-to-solution in a multi-
tenant out-of-control infrastructure?

7. IaaS issues for HPC/HTC SaaS
Failures of sites. Needs Fault-tolerant
design.
Application Performance Variability
between deployments. Needs elasticity.
– Different IaaS back-end servers.
– Multi-tenancy. Sharing resources among IaaS
customers.
– Different Cloud providers.
– Evolution of IaaS infrastructure.
J. Schad, et al, Runtime Measurements in the Cloud:
Observing,Analyzing, and Reducing Variance., Proceedings of
the VLDB Endowment, Vol. 3, No. 1, 2010

8. Proposal: Autonomous Virtual
Cluster Architecture

9. Virtual Cluster Architecture

10. Virtual Cluster single site
NFS
Cluster
management:
OGS + custom
scripts

11. Virtual Cluster-two sites

12. Fault-tolerant VC two sites

13. Elasticity Engine
Controls number of CEs based on Key
Application Performance measurements.
Enlarges the cluster to keep performance
and fulfill deadlines.
Decreases size if App. Performance is
higher than needed, to decrease costs.

14. Proof-of-Concept Experiments

15. BonFIRE Infrastructure
Vendor Freq.
(GHz)
Cores RAM
(GB)
Intel 2.33 2*2 4
AMD 1,7 2*12 48
Intel 2,5 2*4 32
Intel 2.93 2*4 24
INRIA: Vendor Freq. (GHz) Cores RAM
(GB)
Intel 3.2 2*2 2
Intel 2.66 2*2 8
AMD 2.6 4*12 196
AMD 2 2 4
Intel I7 2.53 2 4
Intel I7 2.1 4 8
Intel Atom 1 2
AMD
T56N
1.65 2 2
HLRS:
Cloud Manager:
OpenNebula 3.0

16. DISTRIBUTED VIRTUAL CLUSTER
EXPERIMENT
VCOC, FIRE Engineering Workshop, Ghent, Nov. 6th – 7th 2012

17. Application execution. One vs Two sites
 VC Conf.: Distributed VC (_dist)
 BonFIRE sites:
– INRIA: Master + CEs
– HLRS: CEs
 Deployment time decreases.
 App:Two sites faster than one site.
 But because second site has better
CPUs.
 Impact of deployment ~ 10% total
time.

18. SPECIFIC DEADLINE OBJECTIVE
EXPERIMENT
VCOC, FIRE Engineering Workshop, Ghent, Nov. 6th – 7th 2012

19. Horizontal elasticity
 Monitoring application
performance works.
 We have modified software
to produce information more
frequently.
 Execution with deadline.
 Elasticity works.

20. FAULT TOLERANCE EXPERIMENT
WITH ELASTICITY
VCOC, FIRE Engineering Workshop, Ghent, Nov. 6th – 7th 2012

21. Virtual Cluster
SYNC

22. Fault-tolerance
 BonFIRE sites:
– HLRS (Master + 4 CEs)
– INRIA (Shadow + 4 CEs)
 Demanded performance
(500H/s)
 Fault simulated putting HLRS
VMs in CANCEL.
 INRIA Shadow took control of
cluster.
 Elasticity worked, demanding
more CEs to INRIA.

23. CONCLUSIONS
VCOC, FIRE Engineering Workshop, Ghent, Nov. 6th – 7th 2012

24. Conclusions
 Distributed VC can be used to speed up HTC
applications.
 Elasticity Engine based on Key Application
Performance indicator for HTC works.
 High QoS can be provided in VC using
distributed VC + elasticity.
 BonFIRE provides infrastructure for experiments
about new concepts and services on Cloud.

25. THANKS
Questions?
agomez@cesga.es