An efficient algorithm for the bursting of
Service-based applications in hybrid Clouds
Abstract
Enterprises are more and more using hybrid cloud environments to deploy and run
applications. This consistsin providing and managing software and hardware resources within the
enterprise and getting additional resources providedexternally by public clouds whenever this is
needed. In this later case, deployment of new applications consists in choosing aplacement of
some components in the private cloud and some others in the public cloud. To tackle this NPhard problem, we haveproposed in a previous work an approximate approach based on
communication and hosting costs induced by the deploymentof components in the public cloud.
In this paper, we go further and propose a new efficient algorithm adapted for servicebasedapplications modelled that can be not only described as behavior-based but also as
architecture-based compositions of services
Existing System
Scalability of applicationsand platforms, platform heterogeneity andapplication division
across clouds can be difficultto manage.
In a previous work, we have proposed an algorithmthat behaves in a polynomial time and
approximatesthe optimal bursting solution. The proposedalgorithm is efficient when the SBA can
be representedby a sparse graph of services. It is mainly the casewhen the composition of
services of the consideredSBA is behavior-based.
When we visited existing work on placement ofresources at different levels such as
Software as a Service (SaaS), Platform as a Service (PaaS), Infrastructure as a Service (IaaS),
wefound out that they are not suitable to the consideredproblem of this paper. Indeed, they do not
considercommunication between services or do not considerhybrid situations
Proposed System
In this paper, we are interested inapplication division across clouds and particularly
thedivision of service-based applications (SBAs for short)in hybrid clouds.
When deploying SBAs in a hybrid cloud, their division (bursting) in the public and
privateclouds consists in choosing components/services tobe deployed in the public cloud and
those to bekept in the private cloud.
Inthis paper, we are mainly interested in communication and hosting costs and we do
not deal with security,privacy and other related properties.
Our proposedefficient algorithm for the bursting of SBAs in hybridclouds
Advantage:
Cloud environment differs from traditional environmentson the fact that it
(1) is massively scalable,
(2) Can be encapsulated as an abstract entity that delivers different levels of
services to customers outside the Cloud,
(3) Is driven by economies of scale,
(4) Can be dynamically configured (via virtualization or other approaches) and
(5) Can be delivered on demand
Future Work:
In our future work, we will consider additional parameters such as security and privacy of
hosting and communications costs as criteria for service bursting of SBAs in hybrid clouds.
Algorithm:
Forward-Backward-Refinement (FBR) algorithm
After the presentation of the procedures Forward,Backward and Refinement and the first
algorithmcalled Forward - Backward, Algorithm 5 presentsour efficient approach called Forward
- Backward - Refinement algorithm (FBR algorithm for short).It is based on three combinations
of the proceduresForward, Backward and Refinement. The first combinationcalls first the
Forward procedure, and then theBackward procedure and finally the Refinementprocedure (see
Algorithm, lines 1-3). The secondcombination calls first the Forward procedure, and thenthe
Refinement procedure and finally the Backwardprocedure (see Algorithm, line 1 and lines 4-5).
The third combination places all the application nodes inthe public cloud then it calls the
Backward procedureand finally calls the Refinement procedure (see Algorithm5, lines 6-9).
Finally, our algorithm choosesthe cheapest solution of these above presented combinations(see
Algorithm, lines 10-12).
Modules:
1. Hybrid Cloud
Cloud environments can bepublic, private or hybrid. A public cloud (external
cloud) is a cloud that provides cloud resourcesand services to the public. A private cloud
(internal cloud) is an enterprise owned or leased cloud.In general, a hybrid cloud is a
composition of twoor more clouds of different models. Nevertheless, wedefine, in this
paper, a hybrid cloud as a compositionof one public cloud and one private cloud. Such
acloud is an environment in which an enterprise has itsown private cloud that provides
and manages someinternal resources and only uses external resourcesprovided by the
public cloud when needed.
.
2. private/public clouds
In public or private clouds but not for hybrid clouds.Indeed, in hybrid cloud
communication costs betweenservices depend on the placement of services wherepublic
and private communications should be differentiated.Indeed, the placement of
applications inpublic/private clouds is a matter of placement of avirtual network (that
represents an application) ona physical network that represents the cloud nodesand links.
The problem is then to minimize the communication(and other non-functional properties)
inthe placement. The communication is of the sametype (in a cloud) while in our problem
and contextthe communications are of two types (hybrid communicationand public
communication).
3. Behavior-based compositions
A SBA composed using a behavior-based specificationcan be described as a
structured process whichconsists of a set of process nodes and transitionsbetween them.
A process node can be service, Or-Join, Or-Split, And-Split or And-Join. And-Joins
andOr-Joins should have at least two ingoing transitionsand at least one outgoing
transition. And-Splits andOr-Splits should have at least one outgoing transitionand at
least two ingoing transitions. Non-initial andnon-final services have one ingoing
transition and oneoutgoing transition.
4. Architecture-based compositions
A SBA composed using an architecture-based compositioncan be described as a
set of linked components.A component provides one or more services. It mayconsume
one or several references, which are servicesprovided by other components. Connection
of onereference and one service is realized by a wire.
The example is a composition of four services. TheStore service provides the
interface of the on-linestore. The Catalog service which the Store service canask for
catalog items provides the item prices. TheCurrency_Converter service does the currency
conversionfor the Catalog service. The Shopping_Cart serviceis used to include items
chosen from the Catalogservice.
5. SBA and deployed SBA graphs
A SBA like the one presented in Figure 1 as a graph. Services, Or-Join, Or-Split,
And-Split and And-Join nodes will be represented by graph nodes and connections/
transitions between services will be represented by edges. Nodes are identified by an ID
(a URI or a number) and characterized by an amount of units of hosting resources. Edges
are characterized by an amount of communications units which refers to the amount of
traffic that is transferred on the considered edge.
HARDWARE & SOFTWARE REQUIREMENTS:
HARDWARE REQUIREMENTS:
System
:
Pentium IV 2.4 GHz.
Hard Disk
:
40 GB.
Floppy Drive
:
1.44 Mb.
Monitor
:
15 VGA Color.
Mouse
:
Logitech.
Ram
:
512 MB.
SOFTWARE REQUIREMENTS:
Operating system
:
Windows XP Professional.
Coding Language
:
ASP.NET MVC