A Multi-Tenant Framework for Multimedia Conference System

Transcription

1 2013 8th International Conference on Communications and Networking in China (CHINACOM) A Multi-Tenant Framework for Multimedia Conference System Wang Shaofeng,Shang Yanlei,Tian Yue The State Key Lab of Networking and Switching Beijing University of Posts and Telecommunications Beijing,China wangshaofeng1996@gmail.com,shangyl@bupt.edu.cn,tianyue525@gmail.com Abstract Multimedia conference system is becoming increasingly popular among enterprises and government departments by right of its efficiency and cost-saving features. It supports people in different places share audio, video and documents to achieve real-time communication. However, traditional multimedia conference system can t meet users personal and individual needs. Multi-tenancy has been proposed as a solution to the problem. It allows multiple tenants to share a single application instance securely. With a multi-tenant architecture, each tenant works with a customized virtual application instance. In this paper, we design and implement a multi-tenant architecture which supports the system with customizability and scalability. Keywords-multi-tenant; multimedia conference system; SaaS; OpenStack I. INTRODUCTION With the rapid development of economy and the globalization of trade, cross-regional cooperation and communication become more and more frequent. Multimedia conference system well satisfies such demands of people s daily life. It supports individuals or organizations in different places to share audio, video and documents through transmission network and multimedia devices and provides real-time communication. Multimedia conference system has obtained the rapid development with the help of the maturity of Internet application service and the wide spreading of broadband access technology. The existing multimedia conference systems usually support the following functions such as video and audio sharing, chatting, cooperative document handling, electronic whiteboards, desktop sharing, multi point file transfer, and particularly a multicasting communication facility. Our multimedia conference system supports multiple types of terminals, for example, the conference television, telephone, SIP terminal and mobile terminal using different operating system including Symbian, Windows Mobile, MAC OS and Android[1]. With the popularity of the multimedia conference system, more and more users from different fields come to use the multimedia conference system in their daily life. People work in different fields require for personalized and particular services. The unified service system can t satisfy such demands. Multi-tenant technology has been proposed as a solution to the above problem. Multi-tenant is an architecture in which a single instance of a software application serves multiple customers. Each customer is called a tenant. What s important, each customer may include a number of users. Tenants may be given the ability to customize some parts of the application, such as the subscribing the different services of our multimedia conference system, including video and audio sharing, cooperative document handling and so on. There have been a lot of efforts to build multi-tenant frameworks. Motivated by the success of SaaS[2], multi-tenant has wide traction. The multi-tenant approach brings in lots of benefits. With a multi-tenant architecture, service providers have the ability to ensure the lowest cost of service delivery. A multi-tenant infrastructure makes it easy to increase capacity when more horsepower is required, which resulting in improved profit margin for service provider through reduced delivery costs and decreased service subscription costs for clients. This paper design and implement a multi-tenant framework for multimedia conference system. The primary contributions of this paper are the decoupling of the system s modules, which plays as the prerequisite of the system being customized, and the design and implementation of the multi-tenant architecture that enables multiple users to consume their customized services. Rest of the paper is organized as follows. The next section discusses some related works. Section III presents the architecture of the multi-tenant frame in detail. Following Section IV presents the implementation of the system in detail. Some analysis and results in section V. And finally the Section VI concludes the paper. II. RELATED WORK Multi-tenant was first proposed in late 1960s, companies rented space and processing power to reduce computing expenses and they also reused their existing applications, with a separate entry field which can specify their customer account ID. Actually, it s what the Application Service Providers [3] had done make multi-tenant first came to most people's attention. Multi-tenant application is a more mature architecture which enables a similar service with lower operational cost. In a multi-tenant environment, all clients and their users consume the service, running on the same operating IEEE

2 system, on the same hardware, with the same data-storage mechanism. The four-level SaaS maturity model[4] is one of the first discussions that made a significant effect on multi-tenant research. It s used to determine the configurability, multitenant efficiency, and scalability of the application[5]. In Level 1, each tenant has a dedicated server running its instance of the application and is able to customize the installation in the same way as self-hosted applications. While in level 2, the application serves configurable instances to different tenants. Each tenant could configure their own instance. Multi-tenant efficiency to a SaaS application is introduced and emphasized in the Level 3. Each tenant is served by a single instance. Same applications are served to multiple customers who can customize these through configuring a self-service tool. It uses separate metadata to tailor the application that satisfied the needs of each tenant. Level 4 adds scalability to level 3 offering. A load balancer is introduced to maximize the utilization of storage and processing power in this level. It allows creation of new instances and adds them to the dynamic pool of instances, in which way it achieves the target of being scalable. In a multi-tenant enabled service environment, requests from different tenants are served simultaneously by one or more hosted application instances that based on the shared hardware and software infrastructure [6]. There exist two kinds of multi-tenant patterns: multi-tenant as single instance and multiple instances [7]; the former serves many users using the same instance. It supports all tenants by a single shared application instance over various hosting resources whereas the latter serves users by running multiple instance. It supports each tenant with its customized application instance over the same operating system, a shared hardware or a middleware server in a hosting environment. Our proposed solution falls under the multiple instances. III. ARCHITECTURE OF MULTIMEDIA CONFERENCE SYSTEM We have designed and implemented a multi-tenant architecture for multimedia conference system. The framework supports customization, scalability, and sharing of computing resources as showed in Figure 1. We analysis the architecture from the three aspects. Figure1 The architecture of multimedia conference system A. The VM Calculator This model comprises three approaches which take advantage of the multi-tenant nature of SaaS applications in order to improve the workload distribution and instantiate the number of cloud resources that are really needed. The first approach is the authentication which verifies the users legitimacy. The second approach is the customization which provides users a subscription interface to execute the customization. The third approach would be the VM allocation. We have developed and implemented a mechanism to figure out which VM instance tenants should link to, by given a list of instances and their capability details. The Authentication Get the access point for a SaaS platform and its deployed applications is the first step before we could consume the service. We have developed a web application with specific characteristics for managing authentication, security and access list control. Once the user has been authenticated using username and password, the web application creates a session cookie with all this information and stores it within the user session. In this way, each user is linked to this information session and all subsequent requests are identified through this session cookie. The Customization Once the users have been authenticated, they arrive at the customization module, which presented two choices: create a conference or join in an existing conference. In this module, users could custom the services they need by specific metadata or join in a customized conference. The more details will be showed in the next section. The VM allocation Each tenant has its own service requirements depending on the number of its active users and the applications that are accessed. In order to assign values for virtual machine (VM) allocation, a profile-based approach, which was first proposed by Y. Jie[8], is used in our system. The profile describes the topology and characteristics of the deployed virtual instance cloud and server cluster. Based on the metadata that tenant has submitted, we could calculate what characteristics the virtual machine should contain, and then locate the specific instance provides the service tenant wants to custom according to the profile. B. The Instance Manager Layer OpenStack is an Infrastructure as a Service (IaaS) cloud computing project that is free open source software released under the terms of the Apache License. The project aims to deliver solutions for all types of clouds by being simple to implement, massively scalable, and feature rich. The technology consists of a series of interrelated projects delivering various components for a cloud infrastructure solution. This cloud platform will allow create on-demand virtual machines over a hardware infrastructure and deploy the system presented previously. The multimedia conference system is a Tomcat-based architecture, so it is possible to distribute one Tomcat instance per VM thus enabling scalability based on the number of users. It is 162

3 necessary to create on demand VMs for each Tomcat instance we want to deploy. Thus, it a VM image was created with the multimedia conference system to be deployed within each VM. This creation was performed through OpenStack API. Also, OpenStack provide the interface to manage all the VMs, users could custom their horizon using the dashboard module provided by OpenStack. C. The Data Store Layer There are two types of data involved in our system, the metadata and the business data. The metadata is used to tailor the instance to the needs of each tenant while the business data is produced and needed during the conferencing time. IV. IMPLEMENTATION OF THE MULTIMEDIA CONFERENCE SYSTEM The multi-tenant architecture of multimedia conference system is implemented by the two part of work: the implementation of the core web application and the conference servers cluster management. A. The Core Web Application The core web application is a web application with specific characteristics for managing tenant-based authentication, security and access list control. It creates tenant-level granularity and separates execution contexts for different tenants. It contains three modules as described above. When user comes to register and use our system, he will experience the states as showed in Figure 2. Figure 2 the state user experiences a) Login View: This is the first view of the system. User comes to the login page and enters the username, password and verification code, and then requests for authorization. When the server receives the request, it queries the database to get the user s authority. Once the user verified to be valid, the server will create a session cookie with all this information and store it within the user session cookie. All the user s subsequent requests would be identified through this session cookie. b) Welcome View: When user has been signed, he comes to this page. This module provides create a conference and join in a conference functions. Users can select create a conference to book a conference. By selecting join a conference users can check the database to get the conference information. c) Customization View: If user clicks the button to create a conference, the customization view showed in Figure 3 appears. Figure 3 View of the customization There are many parameters users need to assign in the customization form. Some of them effect the allocation of the VM. That s the so-called metadata, including the screensize, screenresolution, resolutiondetail, confstyle, requiredatashare, datasharestyle, requirechat. Users custom their special services by selecting different metadata. What should be noted is that the participants of the customized conference are also provided. As we know, a tenant is a customer that uses or provides a SaaS application. In our system, a tenant is a customer of conference service. It includes all the members of the conference including the chairman and participants. d) VM Allocation: This is the core module of the web application. First, we read out the data send by users and then pick out the metadata. We could find out users requirement about the VM capability according to the metadata. An important thing we should do in the preparatory period is that we should have figured out the capability of each VM instance. Actually, we maintain a table called instanceinfo in the database. It contains the information of all VM instances in our cluster. Each record represents one instance and it is identified by a unique id. The record also contains the following fields: the VM location and the capability of the instance. In this way, we can check all the information in database. We compare the result that figure out by the metadata and the capability of each instance listed in instanceinfo table. And then, we could get one record that matches user s requirement best. Finally, we send the value of the VM location field to user as a response. e) Query Conf Msg: When user clicks the button to join an existing conference, he sends a request to the server to check whether he is contained by an active conference. If he is, the server would response the VM location. Otherwise, the server would return none. As described in section c), When some customs a conference, he select the participants at the same time. And the list of the participants would store in database when the server 163

4 executes the VM allocation. The list is needed in this module. When users choose to join a conference, they would firstly query the database by his unique Id to know whether they are contained in an active conference. If they are, they could locate the conference Id and which VM it belongs to, and then they just need to link to the VM and join in the conference. No matter user chooses creating a conference or joining into a conference, he will receive a string contains the instance location. And then the user simply redirects to the instance and consumes the subsequent conference services offered by the correct VM instance. B. The Conference Servers Custer Management We use OpenStack as the management portal. We have deployed the OpenStack environment and tested the multimedia conference system. There are 4 servers in our cluster, a controller node, a network node and two computer nodes. The network node manages the network of the cluster while the controller node manages all the nodes. We have created several VM instances over the computer nodes. Each instance runs a particular multimedia conference system application. We have also installed the dashboard provided by the OpenStack on the controller node. The dashboard module is a reference implementation of a Django site that uses the horizon app to provide web-based interactions with the various OpenStack projects. Figure4 shows the default horizon after we login the dashboard. It supports user create, start, suspend, shutdown, remove an instance whenever it s needed. Figure 4 The dashboardview of OpenStack V. EXPERIMENTS AND EVALUATION After setting up the tenant-based components and deploying them into the Tomcat container, we have conducted a series of experiments. We analysis and evaluate the result in the two ways: the data interaction analysis and the conference interface demonstrate. A. The Data Interaction Analysis The purpose of the data interaction analysis is to verify the effect of the customization module. We analysis the interaction from the three aspects: HTTP connect, data transmit and receive. We could check the data flow from users request to the server s response in the help of the chrome debugger. We send a request to custom a conference to the server, and get the information showed in Figure4. Figure 5The data interaction of customization It can be seen from the Headers tab that the HTTP connection has been established normally, and the Form Data is what we have subscribed in the customization view. When the server receive that request, it read out the form data and format the response, which we have discussed in the formal section, and then response to user. The Response tab shows the data we received from the server. The data is in consistency with the result we are looking forward. It is the location of the VM instance in which our scheduled conference was. When we send a request to join in a conference, we also get the similar information as above. Hence we can make sure that the customization module is working smoothly. B. The Conference Interface Demonstrate Users custom the conference successfully and they do get the important information about the conference location as described above. But whether they are serviced by the correct VM instance is not sure. The purpose of the experiments is to demonstrate users are services by the correct instance they ask for. Two types of customizations are showed in Figure 6. Figure 6The different customizations of conference 164

5 The two pictures are captured during conferences time. The left has big video screen size and the screen is split into 6 sections while the right has a small video screen and its screen is split into 4 sections. What s more, the right one also contains a data share field, where users can share documents and desktop and draw something free on the electronic whiteboard cooperatively. The two customizations use the metadata as showed in table1. screen size TABLE1 THE METADATA CHOICE screen resolution conf style require datashare require chat left big high 6split no yes right small standard 4split yes yes Different customization is corresponding to different services. Figure6 just list two of them. We have designed a series of customizations and deployed them over the OpenStack platform. We have designed and implemented a multi-tenant architecture supports with configurability and scalability. Users can custom services on-demand and developers can easily extend the system to meet users special requirements. VI. CONCLUSION Multimedia conference technology has made a great success and multimedia conference system provides a quick and convenient communication way, but the existing multimedia conference can t meet the demands of individuation. In this paper, we have designed and implemented a multi-tenant architecture based on multimedia conference system which supports the system with customizability and scalability. A key promise of multi-tenant is improved utilization. In order to achieve optimal utilization it is necessary for the system to scale elastically. In our work, we make good use of the feature of OpenStack being simple to implement, massively scalable and easy to manage and maintain, which optimally improved the utilization. Resource allocation has a significant impact in cloud computing, especially in pay-per-use deployments where the number of resources is charged to application providers. As further research of the multi-tenant architecture based on the multimedia conference system, we recommend some work to be done to improve and continue validating the proposed solution. It is recommendable to add a load balancer module into the core web application. What s more, not only the capacity of the VM, but also other kind of resources can be defined to be metered to load balance such as bandwidth, storage, transferred data or database connectivity. ACKNOWLEDGMENT We would like to thank Zhang Yundu, Weng Meizhen, Yang Nan and Lei Xiaojiang for their assistance and comments. The work presented in this paper is supported by the National Grand Fundamental Research 973 Program of China (2011CB302506), the National Key Technology Research and Development Program of China Research on the mobile community cultural service aggregation supporting technology (2012BAH94F02), and the Novel Mobile Service Control Network Architecture and Key Technologies (2010ZX ). REFERENCES [1] Jingjing, Ha, et al. "The Design and Implementation of Multimedia Conference Mobile Terminal Application." Wireless Communications Networking and Mobile Computing (WiCOM), th International Conference on. IEEE, [2] M. Turner, D. Budgen, and P. Brereton, Turning software into a service, Computer, pp , [3] L.Tao, Shifting Paradigms with the Application Service Provider Model, IEEE Computer Society. Computer, vol. 34,pp [4] Chong, Frederick, and Gianpaolo Carraro. "Architecture strategies for catching the long tail." MSDN Library, Microsoft Corporation (2006): [5] Pathirage, Milinda, et al. "A multi-tenant architecture for business process executions." Web Services (ICWS), 2011 IEEE International Conference on. IEEE, [6] Guo, Chang Jie, et al. "A framework for native multi-tenancy application development and management." E-Commerce Technology and the 4th IEEE International Conference on Enterprise Computing, E-Commerce, and E-Services, CEC/EEE The 9th IEEE International Conference on. IEEE, 2007 [7] Espadas, Javier, et al. "A tenant-based resource allocation model for scaling Software-as-a-Service applications over cloud computing infrastructures." Future Generation Computer Systems 29.1 (2013): [8] Jie, Yang, Qiu Jie, and Li Ying. "A profile-based approach to just-intime scalability for cloud applications." Cloud Computing, CLOUD'09. IEEE International Conference on. IEEE,