2014 IEEE/ACM 7th International Conference on Utility and Cloud Computing
SLA Assured Brokering (SAB) and CSP Certification in Cloud Computing Shyam S. Wagle LAST-JD, University of Turin, Italy
[email protected]
Abstract—Due to lack of information of the cloud service providers (CSPs), customers can not easily choose services according to their requirement and due to vendor lock-in and lack of interoperability standards among cloud service providers, customers cannot switch the providers once services are subscribed from CSPs. Recently proposed third party architecture which is called cloud broker can access inter-cloud and provides services to the customers according to their requirement but providing SLA based cloud services as per their requirement is still missing in current researches. In our work, we propose the SLA assured brokering framework which matches the requirements of the customer with SLA offered by CSPs using similarity matching algorithm and willingness to pay capacity for the services. It also measures the services offered by CSPs for certifying and ranking the CSPs. Keywords— SLA, Matching,Certifying
Cloud
Brokering,
Similarity
I. INTRODUCTION Each customer expects cloud services according to their requirement but it is very difficult to get the services exactly according to their requirement. From cloud service providers’ point of view, it is not possible to fulfill all the expectations of each customer of different categories. Customer prefers some feature of one cloud service provider and some features of another cloud service provider. But due to lack of information about the CSPs and due to lack of interoperability standard among cloud providers, customers cannot easily switch the providers once services are subscribed from CSPs when they do not fulfill the expectation of the customers. In this context it is necessary do develop a framework which access all the resources of the different service providers and provides the services according to the requirement of the customers as well as to develop the audit trail which provides the actual measurement of the services offered by the cloud providers. In our research work, 1) First, we develop the cloud brokering architecture which matches the costumers’ requirement. Customers’ requirements are matched using SLA templates offered by CSPs and provides the service package based on their requirement and willingness to pay capacity of them for the services. 2) Instead of offering SLA based services, our framework also measures the actual services offered by CSPs and compares with SLA offered by 978-1-4799-7881-6/14 $31.00 © 2014 IEEE DOI
corresponding CSPs for CSP certification and ranking the CSPs. Cloud brokering is a new architectural framework which integrates the resources from different cloud service providers. Recently, cloud brokering is receiving a lot of attention to the research industry. But there are very limited researches in our proposed area. In [1] authors have proposed the SLA based service brokering in inter-cloud environment. They have proposed the conceptual model for SLA management and interoperability feature but SLA matching mechanism is missing in their work. The authors in [2], they have proposed SMICloud which compares the cloud services and ranks the CSPs based on AHP [5] but main question in this process is who will assign the relative weight of each parameter. Comparison and verification of service offered between actual measured data from CSPs premises and SLA template is our novel approach. Consumers can easily get services according to their requirement using our framework as well as our framework certifies the cloud service providers as an independent 3rd party verifier which ensures the customer’s trust level towards CSPs. II. PROPOSED FRAMEWORK Figure 1 shows our proposed framework for SLA assurance in cloud brokering and certifying CSPs. These are the main modules in our proposed framework: A. Cloud Users In our work, we have categorized cloud users in different sectors: General users, Banking sector users and biomedical sector users. B. Cloud Service Providers It contains multiple data centers with different cloud resources. Cloud broker can access the cloud services offered by cloud service providers and provide the services to the customers according to their requirement using different matching algorithm. Generally, cloud service providers provide the information about the status of the cloud premises like server load, CPU utilization etc. but it may not be trustable without third party verifier. For that purpose, we put sensors in CSP premises to receive the exact information of the services offered by service providers. These values are compared with parameters mentioned in SLA template.
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C. Inter-cloud Gateway This is the module which interconnects with multiple cloud providers. It contains standard APIs to interconnect with different cloud service providers. In our work, we do not focus on user interface module and inter-cloud gateway.
provides scoring to each cloud providers based on sum of deviation in offered services. This ranking information of each cloud service providers will be usable for the cloud users and cloud brokers to select the services based on users’ requirement. Regulatory bodies can utilize this information for the regulatory enforcement to the cloud providers. Cloud service providers can also get benefited from this scoring value so that they can improve their service quality. III. RESULT VALIDATION
Fig. 1. Proposed Framwork for SLA Based Brokering and Certification
D. Service Matching and Monitoring Module In our work we use different matching algorithm to match the cloud services offered by the cloud service providers. For similarity matching, we use different matching algorithm proposed by [3] and [4] based on OWL-S. x Word, Number and Sentence Matching Algorithm: This algorithm, it matches the words and numbers interested by cloud customers. Whole sentence matching is not as easy like word matching. For the sentence matching we use key word, word order and sentence length similarity approach. x Fuzzy Concept Matching Algorithm: Words, sentences and numerical values interested by consumers are not always matched with SLA parameters offered by the cloud providers but all attributes are not perfectly matching each other. In this case we use fuzzy matching algorithm to decide the actual services which are not possible for perfectly matching. Different fuzzy levels show the matching levels of the parameters. E. Service Packaging Module This service packaging module offers the packaged services to the targeted consumers based of SLA requested and willingness to pay capacity for the services. We propose different packages based on QoS and price rate. F. Cloud Verifier As shown in Figure 1, it collects the information from cloud service providers’ premises. As mentioned above, real status of the cloud service providers’ data are collected using sensors in cloud service premises. This module in our framework provides the two major functionalities: x Certification of the CSPs: This module compares the exact services offered by cloud service providers with SLA agreement between cloud service provider and consumer. If measured values meet with the SLA parameters, CSP will be verified otherwise feedback will be sent to the corresponding service providers for the correction according to SLA template. x Scoring the CSPs based on service offered: After comparing the measured values with SLA parameters, this module
We will develop multi agent framework to collect actual data from the cloud service providers’ premises. To validate our work, we will extend the Greencloud [6] simulator which is now limited for energy efficient cloud computing. In the first phase, we will develop simulated scenario to provide the services to the consumers based on their requirement. It contains following sub-modules: x Cloud Service Providers with different resources (Data centers, network bandwidth, storage capacity etc.) x SLA template (individual SLA of each cloud provider) x Cloud Broker x Cloud users In the second phase, we develop audit trail to verify the services offered by cloud providers and rank the cloud service providers based on their service provided to the customers. It contains following tasks: x Data collection using sensors from cloud premises x Analysis of collected data from multi-agent framework of CSPs x Certification and scoring of the service providers IV. CONCLUDING REMARKS In this proposal, we presented our conceptual framework for providing SLA assured brokering in cloud computing and comparing the actual values measured from CSP premises with SLA template offered by cloud providers. Our framework also ranks the CSPs according to the total deviation of services measured with SLA committed with customers by CSPs.
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