Category: cloud Computing

Cloud Computing Software as a Service (SaaS) ”; Previous Next Software-as–a-Service (SaaS) model allows to provide software application as a service to the end users. It refers to a software that is deployed on a host service and is accessible via Internet. There are several SaaS applications listed below: Billing and invoicing system Customer Relationship Management (CRM) applications Help desk applications Human Resource (HR) solutions Some of the SaaS applications are not customizable such as Microsoft Office Suite. But SaaS provides us Application Programming Interface (API), which allows the developer to develop a customized application. Characteristics Here are the characteristics of SaaS service model: SaaS makes the software available over the Internet. The software applications are maintained by the vendor. The license to the software may be subscription based or usage based. And it is billed on recurring basis. SaaS applications are cost-effective since they do not require any maintenance at end user side. They are available on demand. They can be scaled up or down on demand. They are automatically upgraded and updated. SaaS offers shared data model. Therefore, multiple users can share single instance of infrastructure. It is not required to hard code the functionality for individual users. All users run the same version of the software. Benefits Using SaaS has proved to be beneficial in terms of scalability, efficiency and performance. Some of the benefits are listed below: Modest software tools Efficient use of software licenses Centralized management and data Platform responsibilities managed by provider Multitenant solutions Modest software tools The SaaS application deployment requires a little or no client side software installation, which results in the following benefits: No requirement for complex software packages at client side Little or no risk of configuration at client side Low distribution cost Efficient use of software licenses The customer can have single license for multiple computers running at different locations which reduces the licensing cost. Also, there is no requirement for license servers because the software runs in the provider”s infrastructure. Centralized management and data The cloud provider stores data centrally. However, the cloud providers may store data in a decentralized manner for the sake of redundancy and reliability. Platform responsibilities managed by providers All platform responsibilities such as backups, system maintenance, security, hardware refresh, power management, etc. are performed by the cloud provider. The customer does not need to bother about them. Multitenant solutions Multitenant solutions allow multiple users to share single instance of different resources in virtual isolation. Customers can customize their application without affecting the core functionality. Issues There are several issues associated with SaaS, some of them are listed below: Browser based risks Network dependence Lack of portability between SaaS clouds Browser based risks If the customer visits malicious website and browser becomes infected, the subsequent access to SaaS application might compromise the customer”s data. To avoid such risks, the customer can use multiple browsers and dedicate a specific browser to access SaaS applications or can use virtual desktop while accessing the SaaS applications. Network dependence The SaaS application can be delivered only when network is continuously available. Also network should be reliable but the network reliability cannot be guaranteed either by cloud provider or by the customer. Lack of portability between SaaS clouds Transferring workloads from one SaaS cloud to another is not so easy because work flow, business logics, user interfaces, support scripts can be provider specific. Open SaaS and SOA Open SaaS uses those SaaS applications, which are developed using open source programming language. These SaaS applications can run on any open source operating system and database. Open SaaS has several benefits listed below: No License Required Low Deployment Cost Less Vendor Lock-in More portable applications More Robust Solution The following diagram shows the SaaS implementation based on SOA: Print Page Previous Next Advertisements ”;

Cloud Computing Infrastructure ”; Previous Next Cloud infrastructure consists of servers, storage devices, network, cloud management software, deployment software, and platform virtualization. Hypervisor Hypervisor is a firmware or low-level program that acts as a Virtual Machine Manager. It allows to share the single physical instance of cloud resources between several tenants. Management Software It helps to maintain and configure the infrastructure. Deployment Software It helps to deploy and integrate the application on the cloud. Network It is the key component of cloud infrastructure. It allows to connect cloud services over the Internet. It is also possible to deliver network as a utility over the Internet, which means, the customer can customize the network route and protocol. Server The server helps to compute the resource sharing and offers other services such as resource allocation and de-allocation, monitoring the resources, providing security etc. Storage Cloud keeps multiple replicas of storage. If one of the storage resources fails, then it can be extracted from another one, which makes cloud computing more reliable. Infrastructural Constraints Fundamental constraints that cloud infrastructure should implement are shown in the following diagram: Transparency Virtualization is the key to share resources in cloud environment. But it is not possible to satisfy the demand with single resource or server. Therefore, there must be transparency in resources, load balancing and application, so that we can scale them on demand. Scalability Scaling up an application delivery solution is not that easy as scaling up an application because it involves configuration overhead or even re-architecting the network. So, application delivery solution is need to be scalable which will require the virtual infrastructure such that resource can be provisioned and de-provisioned easily. Intelligent Monitoring To achieve transparency and scalability, application solution delivery will need to be capable of intelligent monitoring. Security The mega data center in the cloud should be securely architected. Also the control node, an entry point in mega data center, also needs to be secure. Print Page Previous Next Advertisements ”;