Net-Centric Software and Systems I/UCRC
High-Confidence SLA Assurance for Cloud
Computing Systems and Services
Project Lead: Farokh B. Bastani, I-Ling Yen, Krishna Kavi, and Jeff Tian
Date: April 7, 2011
Copyright © 2011 NSF Net-Centric I/UCRC.
All Rights Reserved.
Problem Description
• Emerging cloud computing paradigm enables
– On-demand access to storage, computing, software, and physical resources
– Integrated capabilities of a large spectrum of networked services and
resources for realizing tasks that are far beyond current practices
 Need SLA to enhance cloud system usability and dependability
• Existing SLA (service level agreement) research: Siloed
– SLA model: Consider agreement for each QoS aspect independently
– Client perspective
• Need to establish SLAs one service at a time, lacking an end-to-end approach
for the client task that require composing multiple services/resources
• Consider individual QoS aspects independently, not potential tradeoffs
– Provider perspective
• Each provider operates independently, lacks a collaborative concept to globally
achieve high SLA assurance while maximizing resource utilization
– No satisfactory solutions to security issues across all layers
• Challenges: Develop a comprehensive SLA model and supporting
environment
2
Proposed Solution
Service Composer
- Perform end-to-end QoS analysis before SLAs
Provider 1
SLA for first service
feedback
May need reservations to avoid new failures
Resource
- Consider
QoS aspectsAdmission
holistically and directly determine
Management
Control
the configuration parameters
to fully control tradeoffs
Local
Improve
SLA model
holistic SLA
S to support
R
QoS
Monitoring
feedback
Form cloud
community
R
R
S
S
R
Admission
Control
feedback
R S
Local QoS
R
S
Monitoring
R
At each provider:
- Consider strict & flexible SLAs
Provider 3
- Develop optimal resource management
Resource
Admission
and admission
control schemes
Management
Control
- Formulation:
optimization problem
with the objective of
- Ensure SLAs are satisfied if resources are sufficient;
if not, adjust resource decisions
feedback
maximizing the gain, given task completion rewards and
QoS
violation Local
penalties
and the available resources
Monitoring
- Admit only
if positive gain
- Local monitoring and online reconfiguration
client
.
.
Integrated SLA Monitoring
.
- Agent based distributed monitoring and
behavior integration
Provider 2
Resource
Management
SLA for second service
...
Fail to get agreement
client
- Rule based approach, formalize SLAs
as rules, events as facts, and use reasoning
to derive the violation situations
- Consider fuzzy violation decision models
- Across providers and resource types
- Proactive SLA assurance (recovery)
Provider N
Resource
Management
Local QoS
Monitoring
Admission
Control
3
2011 New Project Summary
High-Confidence SLA Assurance for Cloud Computing Systems and Services
Tasks:
1. Comprehensive model of cloud SLAs
considering correlations of QoS aspects and
end-to-end QoS requirements
2. Integrated SLA monitoring approach across
providers and resource types
3. Optimal adaptive strategies for assuring
SLAs under normal and failure situations
4. Method of assessing system-level SLAs
based on component-level SLAs
5. Layered collaborative approach for optimally
achieving global SLA assurance by leveraging
resources from multiple cloud domains
Research Goals:
1. Improved SLA models and protocols to
facilitate highly dependable and practically
usable cloud computing
2. Optimal supporting environment for SLA
assurance considering end-to-end QoS and
QoS tradeoffs and achieving local as well as
global monitoring, resource management,
and admission control
Project Schedule:
Task 3: Optimal adaptive SLA assurance
Task 2: Integrated SLA monitoring
Task 1: SLA model
A M
11
J J A
S
O N D
J
F M A
12
Benefits to Industry Partners:
1. Advanced cloud technologies to meet specified
SLAs to a high degree of confidence in spite of
multiple failures
2. Enable cloud computing to be used for critical
applications, including health-care systems,
emergency response systems, defense systems,
transportation systems, etc.
4