Optimal deployment of components of cloud-hosted application for guaranteeing multitenancy isolation

One of the challenges of deploying multitenant cloud-hosted services that are designed to use (or be integrated with) several components is how to implement the required degree of isolation between the components when there is a change in the workload. Achieving the highest degree of isolation implies deploying a component exclusively for one tenant; which leads to high resource consumption and running cost per component. A low degree of isolation allows sharing of resources which could possibly reduce cost, but with known limitations of performance and security interference. This paper presents a model-based algorithm together with four variants of a metaheuristic that can be used with it, to provide near-optimal solutions for deploying components of a cloud-hosted application in a way that guarantees multitenancy isolation. When the workload changes, the model based algorithm solves an open multiclass QN model to determine the average number of requests that can access the components and then uses a metaheuristic to provide near-optimal solutions for deploying the components. Performance evaluation showed that the obtained solutions had low variability and percent deviation when compared to the reference/optimal solution. We also provide recommendations and best practice guidelines for deploying components in a way that guarantees the required degree of isolation

Software-As-A-Service: Implications For Business And Technology In Product Software Companies

Many software organizations are currently transitioning from an on-premises deployment model to the Software as a Service (SaaS) model. If a company restricts changes only in the business or technical perspective, the transition leads to higher costs, poor adoption of the SaaS model, and in the worst case, the company can lose its business. Much literature focuses on changes within one domain and is generally also limited to one perspective. This paper provides stakeholders (i.e. product managers, and business managers) an integrated perspective (business and technological) with a comprehensive framework that covers changes in four domains: business/product structure, revenue logic, customer relationships, and partnerships. The applicability of the proposed framework is assessed with a case study of a large software product vendor. The paper also contributes by providing a new avenue to study SaaS, with an integrated perspective for the organizational transition period. For the industry, this paper suggests a way to assess the impacts of organizational transition towards the SaaS model. With this overview in hand, software-producing organizations can use the comprehensive framework to successfully transition to become SaaS vendors

Configurability, Maturity, and Value Co-creation in SaaS: An Exploratory Case Study

This study answers the research question, “How do value co-creation components – value, offering, value networks, user involvement, and interaction process – change over time as Software-as-a-Service (SaaS) configurability moves toward maturity?” We conducted a case study of GlobalSchool, a SaaS company providing administrative software to small-sized schools. We refined the SaaS maturity model by integrating the concept of self-service. We further assessed configurability (along with SaaS maturity) from the co-creation of value perspective. Our findings show that value co-creation components are dynamic, changing at different maturity levels. We also identified two drivers for change – knowledge and volume of clients. Our study contributed toward the SaaS and value co-creation literature. The managerial implications include the need for SaaS vendors to balance between providing support and self-service, solicit feedback from long-standing clients, and slowly transition clients to the self-service concept

Architecting the deployment of cloud-hosted services for guaranteeing multitenancy isolation.

In recent years, software tools used for Global Software Development (GSD) processes (e.g., continuous integration, version control and bug tracking) are increasingly being deployed in the cloud to serve multiple users. Multitenancy is an important architectural property in cloud computing in which a single instance of an application is used to serve multiple users. There are two key challenges of implementing multitenancy: (i) ensuring isolation either between multiple tenants accessing the service or components designed (or integrated) with the service; and (ii) resolving trade-offs between varying degrees of isolation between tenants or components. The aim of this thesis is to investigate how to architect the deployment of cloud-hosted service while guaranteeing the required degree of multitenancy isolation. Existing approaches for architecting the deployment of cloud-hosted services to serve multiple users have paid little attention to evaluating the effect of the varying degrees of multitenancy isolation on the required performance, resource consumption and access privilege of tenants (or components). Approaches for isolating tenants (or components) are usually implemented at lower layers of the cloud stack and often apply to the entire system and not to individual tenants (or components). This thesis adopts a multimethod research strategy to providing a set of novel approaches for addressing these problems. Firstly, a taxonomy of deployment patterns and a general process, CLIP (CLoud-based Identification process for deployment Patterns) was developed for guiding architects in selecting applicable cloud deployment patterns (together with the supporting technologies) using the taxonomy for deploying services to the cloud. Secondly, an approach named COMITRE (COmponent-based approach to Multitenancy Isolation Through request RE-routing) was developed together with supporting algorithms and then applied to three case studies to empirically evaluate the varying degrees of isolation between tenants enabled by multitenancy patterns for three different cloud-hosted GSD processes, namely-continuous integration, version control, and bug tracking. After that, a synthesis of findings from the three case studies was carried out to provide an explanatory framework and new insights about varying degrees of multitenancy isolation. Thirdly, a model-based decision support system together with four variants of a metaheuristic solution was developed for solving the model to provide an optimal solution for deploying components of a cloud-hosted application with guarantees for multitenancy isolation. By creating and applying the taxonomy, it was learnt that most deployment patterns are related and can be implemented by combining with others, for example, in hybrid deployment scenarios to integrate data residing in multiple clouds. It has been argued that the shared component is better for reducing resource consumption while the dedicated component is better in avoiding performance interference. However, as the experimental results show, there are certain GSD processes where that might not necessarily be so, for example, in version control, where additional copies of the files are created in the repository, thus consuming more disk space. Over time, performance begins to degrade as more time is spent searching across many files on the disk. Extensive performance evaluation of the model-based decision support system showed that the optimal solutions obtained had low variability and percent deviation, and were produced with low computational effort when compared to a given target solution

Market reactions to the servitization of product offerings - An event study on the software as a service model

Servitization is transforming traditional manufacturing and product-oriented firms across industries in many ways. One of these transformations concerns the business models of firms that transform from selling products to provisioning products as a service with product-service systems (PSS). I analyze this form of servitization in the software industry, where the software as a service business model is becoming the standard for most start-ups as well as some big enterprises like Adobe and Autodesk. Event study methodology is applied to 359 software vendors’ announcements of new software as a service offerings between 2001 and 2015, analyzing how installed base, parallel business models and partnerships with external service providers influence the reaction in the stock price of the software vendors. I find that “as-a- service” business models are not perceived as a substitute but rather as a complement for perpetual product sales and that collaboration with specialized service providers for the delivery of the new offering is rewarded by the stock market. I explain the findings with organizational inertia within the software vendors’ organization as well as that of their customers. The findings are used to discuss how companies can manage the inertia by developing new product lines for the PSS model, offering perpetual product sales in parallel and cooperating with third party service providers for the service delivery. Servitization is transforming traditional manufacturing and product-oriented firms across industries in many ways. One of these transformations concerns the business models of firms that transform from selling products to provisioning products as a service with product-service systems (PSS). I analyze this form of servitization in the software industry, where the software as a service business model is becoming the standard for most start-ups as well as some big enterprises like Adobe and Autodesk. Event study methodology is applied to 359 software vendors’ announcements of new software as a service offerings between 2001 and 2015, analyzing how installed base, parallel business models and partnerships with external service providers influence the reaction in the stock price of the software vendors. I find that “as-a- service” business models are not perceived as a substitute but rather as a complement for perpetual product sales and that collaboration with specialized service providers for the delivery of the new offering is rewarded by the stock market. I explain the findings with organizational inertia within the software vendors’ organization as well as that of their customers. The findings are used to discuss how companies can manage the inertia by developing new product lines for the PSS model, offering perpetual product sales in parallel and cooperating with third party service providers for the service delivery.  Keywords: SaaS, Software-as-a-Service, Servitization, Business model transformation, Stock market

A Serverless Distributed Ledger for Enterprises

Enterprises have been attracted by the capability of blockchains to provide a single source of truth for workloads that span companies, geographies, and clouds while retaining the independence of each party’s IT operations. However, so far production applications have remained rare, stymied by technical limitations of existing blockchain technologies and challenges with their integration into enterprises' IT systems. In this paper, we collect enterprises' requirements on distributed ledgers for data sharing and integration from a technical perspective, argue that they are not sufficiently addressed by available blockchain frameworks, and propose a novel distributed ledger design that is ``serverless'', i.e., built on cloud-native resources. We evaluate its qualitative and quantitative properties and give evidence that enterprises already heavily reliant on cloud service providers would consider such an approach acceptable, particularly if it offers ease of deployment, low transactional cost structure, and a combination of latency and scalability aligned with real-time IT application needs

Securing the Deployment of Cloud-Hosted Services for Guaranteeing Multitenancy Isolation

Multitenancy introduces significant error and security challenges in the cloud depending on the location of the functionality to be shared and the required degree of isolation between the tenants. Existing approaches for securing the deployment of cloud-hosted services to serve multiple users have paid little attention to evaluating the effect of the varying degrees of multitenancy isolation on the security and access privilege of tenants (or components). In addition, approaches for securing the isolation of tenants (or components) are usually implemented at lower layers of the cloud stack and often apply to the entire system and not to individual tenants (or components). This study presents CLAMP (Cloud-based architectural approach for securing services through Multitenancy deployment Patterns) to securing the deployment of cloud-hosted services in a way that guarantees the required degree of isolation between the tenants. We evaluated the framework by applying it to a motivating cloud deployment problem. The findings show among other things that the framework can be used to select suitable deployment patterns, evaluate the effect of varying degrees of isolation on the cloud-hosted service, analyse the deployment requirements of cloud-hosted services and optimise the deployment of the cloud-hosted service to guarantee multitenancy isolation