The experimental results validate that Soft-Union significantly reduces the block query time comparing with flooding and BT- like software distribution solutions.
2011 IEEE 4th International Conference on Cloud Computing
Soft-Union: An Overlay based Efficient Software P2P Distribution Scheme Liang Zhong, Chunming Hu, Tianyu Wo, Jianxin Li, Weiji Zeng {School of Computer Science, Beihang University,Beijing 100191, China} {zhongl, hucm, woty, lijx, zengwj}@act.buaa.edu.cn distribution in a large scale manner. The major contributions of this paper are summarized as follows: y Two-layer P2P architecture is adopted in the software distribution system, thus software execution nodes can fetch the softwares block from other nodes. y An effective overlay is proposed to organize software nodes into a software club to reduce the search scope of the software. y Block meta-information distributed placement mechanism and search protocol are proposed to efficiency find the location of blocks. y A prototype of Soft-Union system is designed and implemented in NeTrOS[2] vSaaS system[3][4]. We evaluate the performance of xx through comprehensive experiments on our NeTrOS testbed.
Abstract—Recent years, SaaS (Software as a Service) has become an innovative software delivery model. The traditional centralized software distribution model failed to meet the rapid deployment requirement of distribute software in large scale environment. In this paper, we present Soft-Union: a novel peer-to-peer based software distribution scheme. Soft-Union organizes the nodes sharing the same software into an overlay to reduce the query time. Furthermore, it incorporates a distributed mechanism for meta-information placement mechanism, and a search protocol to balance the query load and shorter the query time of the block meta-information. The experimental results validate that Soft-Union significantly reduces the block query time comparing with flooding and BTlike software distribution solutions. Keywords-SaaS; Software Distribution; Overlay; Peer-toPeer; Search
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INTRODUCTION
In this section, we will describe the definition and the maintenance of Soft-Union overlay. After that, block partition, placement algorithm, and a two-phase searching protocol in Soft-Union overlay will be further discussed.
With the rapid development of computer and Internet technology, the Software as a Service[1] (SaaS), largely enabled by the Internet, becomes an innovative software delivery model for enterprises and individuals to complete the business and private tasks. How to rapidly distribute the software in a large scale environment is a challenge problem within current SaaS delivery model. Many existing software distribution methods are mainly based on the traditional centralized client/server model, which still suffers from the following two problems: First, the centralized server will be the single failure of point if it goes down or under maintenance. Second, the single server will be the critical performance bottleneck if the number of clients becomes larger and larger. Software is dynamically streaming to the target execution nodes in an on-demand manner. Thus, we naturally expect that the peer-to-peer distribution can be implemented in this context, which will scale well with the currently large user basis. In the software streaming distribution scenario, different blocks may have different access frequency. Thus, the requesting load of the meta-information will be different among blocks. Unfortunately, the above unique characteristics in this application scenario make a straightforward adoption of existing P2P system for block sharing suboptimal. For most of the existing P2P systems, the file blocks have the equal access frequency, which makes the meta-information management approach failed to consider the load balance of requesting for different blocks. In this paper, we proposed a peer-to-peer (P2P) based software streaming distribution scheme named Soft-Union, which can be used to accelerate the software streaming
978-0-7695-4460-1/11 $26.00 © 2011 IEEE DOI 10.1109/CLOUD.2011.95
DESIGN OF SOFT-UNION
Figure 1. An example of software union
The basic idea of Soft-Union is to build an overlay over the existing two-layer P2P architecture. In such overlay based architecture, vProcess instances with the same software will be organized into a software union. An example of such a software union overlay is shown in Figure 1. . From Figure 1. , we could see that vProcess instance A, B, C, D, E and F are connected to different software store servers. Since all these instances are executing the same software, they are formed into a software union overlay. In these peers, C and D also act as the tracker peers, which response for hosting the actual block meta-information for 740
the blocks. Three roles have been defined in the Soft-Union scheme: Login Server (LS), Software Store (ST), vProcess Instance (VP). There are two kinds of VP, one is common vProcess, and the other is Tracker.
environment, called SDS (Software Distribution System), which allow us to easily and rapidly distribute the software in a large scale execution nodes. The architecture of SDS service is shown in Figure 4.
Figure 4. The SDS Architecture Figure 2. Block Partition and Placement
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From Figure 2, we could see that the software image is divided into several blocks. Each block of the software will be identified with a block id. All the blocks are also partition into several block groups. One block group is a set of blocks collection. Each block group is also identified with a group id. In our Soft-Union scheme, the meta-information of software blocks are stored in a distribute manner by block group. Servers named tracker response for storing the metainformation. The detail information about the group partition and placement problem will be given in this section.
CONCLUSIONS
In this paper, we proposed a Soft-Union scheme to accelerate the software streaming distribution in the P2P manner. We build an overlay over the existing two-layer P2P software distribution architecture. In order to improve software meta-information query efficiency, software clubs for popular software are established, where execution nodes sharing the same software instance is connected closely. Moreover, a distributed block meta-information storage mechanism and searching protocol are used to effectively query the software blocks. We have implemented Soft-Union in our NeTrOS environment and performed a set of experiments to validate our design and explore the performance. The result shows that the Soft-Union significantly improves software search performance and outperforms the existing approaches. ACKNOWLEDGMENT This work is partially supported by grants from China 973 Fundamental R&D Program (No. 2005CB321803), National Natural Science Foundation of China (Project No. 60703056) and China 863 High-tech Program (Project No. 2008AA01Z118). We would also like to thank members from Network Computing Research team in Institute of Advanced Computing Technology of Beihang University for their hard work.
Figure 3. A Two-phase searching protocol
As we have described in the above section, a Software Store server will be the union master, which responses for the management of the unions of some software. We design a two-phase searching protocol for the vProcess instance to query the meta-information in the scope of the union overlay. The detail procedure of searching protocol is shown in Figure 3. When a vProcess instance wants to query the metainformation of certain block, it will commit a two-phase searching to the system. III.
REFERENCES [1]
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IMPLEMENTATION
[4]
According to the architecture, meta-information placement algorithm and searching protocol described in section 3 and section 4, we implemented a modular software distribution architecture for our NeTrOS testbed
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Ma, D. The Business Model of “Software As A Service" [C]. In 2007 IEEE International Conference on Services Computing (SCC 2007), pages 701-70 July 2007. Jinpeng Huai, Qin Li and Chunming Hu, CIVIC: A Hypervisor Based Virtual Computing Environment [C]. Proceedings of the 2007 International Conference on Parallel Processing Workshops, September, 2007 Liang Zhong, Tianyu Wo, Jianxin Li, Bo Li. vSaaS: A Virtual Software as a Service Architecture for Cloud Computing Environment, e-Science 2009 Poster.December 2009 Liang Zhong, Tianyu Wo, Jianxin Li, Bo Li. A Virtualization-based SaaS Enabling Architecture for Cloud Computing, Proceedings of Sixth International Conference on Autonomic and Autonomous Systems, March 2010
