VISION Cloud Architecture

In vision Cloud application architecture, the DAL is considering a logical entry position to the system, where DAL is ensuring a set of functionalities to the applications including access to the data objects, secure data access, unified access to a federation of data store services and allows changing object of data storage, a storlet [Vil12] in the Cloud. A storlet is a computational mediator which has role to classify the computation and isolating metadata automatically by performing the triggering conditions. In this scope, data storage modifica- tion means create, delete or manage storlets using a user API. According to the software layer architecture in VISION Cloud, the DAL is representing a communication media or translator between application and the storage, where DAL is implementing data access functionalities based on the DOL. The DOL is the lower layer in VISION Cloud application architecture, which implements the core functionalities providing data objects in the application system in order to access Cloud data storage. As a result applications or users have the opportunity to use a common access layer for enabling Cloud data access.

Figure 3.1 shows an abstraction level conceptual architecture of Data Access Layer based on VISION Cloud software context, where applications are communicating to the DAL through a Hypertext Transfer Protocol (HTTP) server request processing and then the DAL is communicating to the DOL, the storage of data objects. In this design concept, it is considered that DAL has implemented with a set of components (i.e. Content Centric Interface (CCI) , Cloud Federation and Interoperability (CFI), Secure Access Interface (SAI) and Computational Storage) and the functionalities depending on DOL, then the basic functionalities including storage operations, metadata management, replication, etc. are performed by DOL. Within DAL, the CCI has the responsibility to keep track the content information, where the CFI has ensured the service quality, both approaches are using metadata to perform the allocated

3.1. VISION Cloud

Application

Data Access Layer

Data Operation Layer

http server – request processing

Content Centric Interface Cloud Federation and Interop. Secure

Access onal Storage Computati-

Figure 3.1.:High Level Conceptual Architecture of the Data Access Layer [AAB+11].

functionalities. Moreover, the SAI is dealing with authentication procedures in the system where the applications are using Computational Storage component for interacting with DOL objects. However, when application communicates to the DAL through a process request, the Management Interface Layer (MIL) also establish a communication tunnel to the application in order to achieve the management functionalities of VISION Cloud. Nevertheless, VISION Cloud implements a layer based application architecture model, which is common and standard approach for a software systems since a few last decades. Designing layering based application is advantageous because in this approach the applications can be implemented with separating different segments and functionalities in a logical blocks or components in software system where components are often reusable [AAB+11].

Technical Architecture

As part of the project work VISION Cloud has presented a detail technical architecture for the entire system on respected to the access layer shown in Figure 3.2. This architecture describes how DAL implements interaction between application and the data storage service. Also, it summarizes the important necessary relations with different components in the system. Additionally, it show a detail functional implementation of DAL, means how DAL performs data access functionalities within the VISION Cloud system. The applications are communicating to the DAL using Representational State Transfer (REST) method request and the authentications are required when calling a functional component. In this master’s thesis we are not currently considering secure data access or data replication, however our goal is to

3. Related Works

adapt the DAL in order to enable Cloud data access. This is relatively similar approach but we have focused on a concrete design how traditional application can benefit access a scaled and stabled data store service in the Cloud to reduce the application complexity instead of using traditional database.

Global View

Data Access Layer Management

Interface Layer

Data Operation Layer Application User Service Placement Service Identity/Policy Repository Storage Service Catalog (logically one for each cont.)

Replication Manager Access Enforcer Object Services Storlet Execution Request Processor Access Manager Content Centric Access Storlet

Manager Identity and Policy Service

Figure 3.2.:High Level Technical Architecture of the Data Access Layer [AAB+11].

Request processor is the only entry position to the application systems communicating to the DAL, where it processes requests form the application and implements basic functionalities including systems performance and scalability features for managing proper distribution to the system. It forwards a request the Access Manager, a access control component to control the systems implementing authentication and authorization. It also handles request by request handler for the MIL to achieve the management functionalities, where MIL is a one of the part of VISION Cloud system besides DAL. However, during processing a request the request handler characterized the request separately for both DAL and MIL. Additionally, in case errors during processing request, it has the responsibility to notify to the application about occurring errors. In the technical point of view there are three components to be considered as main in DAL, such as Content Centric Service, Computational Storage and Secure Access.