Foundations and Technological Landscape of Cloud Computing

The cloud computing paradigm has brought the benefits of utility computing to a global scale. It has gained paramount attention in recent years. Companies are seriously considering to adopt this new paradigm and expecting to receive significant benefits. In fact, the concept of cloud computing is not a revolution in terms of technology; it has been established based on the solid ground of virtualization, distributed system, and web services. To comprehend cloud computing, its foundations and technological landscape need to be adequately understood. This paper provides a comprehensive review on the building blocks of cloud computing and relevant technological aspects. It focuses on four key areas including architecture, virtualization, data management, and security issues

Migrating Monoliths to Microservices-based Customizable Multi-tenant Cloud-native Apps

It was common that software vendors sell licenses to their clients to use software products, such as Enterprise Resource Planning, which are deployed as a monolithic entity on clients’ premises. Moreover, many clients, especially big organizations, often require software products to be customized for their specific needs before deployment on premises. While software vendors are trying to migrate their monolithic software products to Cloud-native Software-as-a-Service (SaaS), they face two big challenges that this paper aims at addressing: 1) How to migrate their exclusive monoliths to multi-tenant Cloud-native SaaS; and 2) How to enable tenant-specific customization for multi-tenant Cloud-native SaaS. This paper suggests an approach for migrating monoliths to microservice-based Cloud-native SaaS, providing customers with a flexible customization opportunity, while taking advantage of the economies of scale that the Cloud and multi-tenancy provide. Our approach shows not only the migration to microservices but also how to introduce the necessary infrastructure to support the new services and enable tenant-specific customization. We illustrate the application of our approach on migrating a reference application of Microsoft called SportStore.acceptedVersio

Multi-tenant hybrid cloud architecture

This paper examines the challenges associated with the multi-tenant hybrid cloud architecture and describes how this architectural approach was applied in two software development projects. The motivation for using this architectural approach is to allow developing new features on top of monolithic legacy systems – that are still in production use – but without using legacy technologies. The architectural approach considers these legacy systems as master systems that can be extended with multi-tenant cloud-based add-on applications. In general, legacy systems are run in customer-operated environments, whereas add-on applications can be deployed to cloud platforms. It is thus imperative to have a means connectivity between these environments over the internet. The technology stack used within the scope of this thesis is limited to the offering of the .NET Core ecosystem and Microsoft Azure. In the first part of the thesis work, a literature review was carried out. The literature review focused on the challenges associated with the architectural approach, and as a result, a list of challenges was formed. This list was utilized in the software development projects of the second part of the thesis. It should be noted that there were very few high-quality papers available focusing exactly on the multi-tenant hybrid cloud architecture, so, in the end, source material for the review was searched separately for multi-tenant and for hybrid cloud design challenges. This factor is noted in the evaluation of the review. In the second part of the thesis work, the architectural approach was applied in two software development projects. Goals were set for the architectural approach: the add-on applications should be developed with modern technology stacks; their delivery should be automated; their subscription should be straightforward for customer organizations and they should leverage multi-tenant resource sharing. In the first project a data quality management tool was developed on top of a legacy dealership management system. Due to database connectivity challenges, confidentiality of customer data and authentication requirements, the implemented solution does not fully utilize the architectural approach, as having the add-on application hosted in the customer environment was the most reasonable solution. Despite this, the add-on application was developed with a modern technology stack and its delivery is automated. The subscription process does involve certain manual steps and, if the customer infrastructure changes over time, these steps must be repeated by the developers. This decreases the scalability of the overall delivery model. In the second project a PDA application was developed on top of a legacy vehicle maintenance tire hotel system. The final implementation fully utilizes the architectural approach. Support for multi-tenancy was implemented using ASP.NET Core Dependency Injection and Finbuckle.MultiTenancy-library. Azure Relay Hybrid Connection was used for hybrid cloud connectivity between the add-on application and the master system. The delivery model incorporates the same challenges regarding subscription and customer infrastructure changes as the delivery model of the data quality management tool. However, the manual steps associated with these challenges must be performed only once per customer – not once per customer per application. In addition, the delivery model could be improved to support customer self-service governance, enabling the delegation of any customer environment installations to the customers themselves. Even further, the customer environment installation could potentially cover an entire product family. As an example, instead of just providing access for the PDA application, the installation could provide access for all vehicle maintenance family add-on applications. This would make customer environment management easier and developing new add-on applications faster

Rethinking Executive Education: A Program for Responding to Sudden Disruptions Caused by Dynamic Complexity

Lately, many social systems (i.e., countries, organizations and projects) are experiencing adverse situations that are characterized as “dynamic complexity.” These situations usually co-produce disruptions in the day-to-day operations as a result of which many social systems become partially extinct. We posit this is because these situations are not clearly recognized by those who are empowered to deal with them. In this paper we propose a new and updated approach to executive education that takes into account the prevalence of dynamic complexity caused by massive changes in the nature of the internal and external environments of a system. We argue that the educational requirements necessary to prepare leaders who have the cognitive capacity to steer through the “perfect storm,” are very different from leading in simple and stable contexts. We suggest that this proficiency emerges from the interaction of relevant skills, accessed experience, knowledge and understanding of the situation, practical wisdom and sound judgment, and relevant personality attributes. We present a model with a multi-layered approach to executive education which addresses how the ability to rapidly assimilate, sort through, and comprehend vast amounts of data/information in order to make the right decisions depends on approaches to learning, knowledge of critical concepts, particularly systems thinking as a mindset/filter, and knowledge of enabling IT

A Survey on Intrusion Detection Systems for Fog and Cloud Computing

The rapid advancement of internet technologies has dramatically increased the number of connected devices. This has created a huge attack surface that requires the deployment of effective and practical countermeasures to protect network infrastructures from the harm that cyber-attacks can cause. Hence, there is an absolute need to differentiate boundaries in personal information and cloud and fog computing globally and the adoption of specific information security policies and regulations. The goal of the security policy and framework for cloud and fog computing is to protect the end-users and their information, reduce task-based operations, aid in compliance, and create standards for expected user actions, all of which are based on the use of established rules for cloud computing. Moreover, intrusion detection systems are widely adopted solutions to monitor and analyze network traffic and detect anomalies that can help identify ongoing adversarial activities, trigger alerts, and automatically block traffic from hostile sources. This survey paper analyzes factors, including the application of technologies and techniques, which can enable the deployment of security policy on fog and cloud computing successfully. The paper focuses on a Software-as-a-Service (SaaS) and intrusion detection, which provides an effective and resilient system structure for users and organizations. Our survey aims to provide a framework for a cloud and fog computing security policy, while addressing the required security tools, policies, and services, particularly for cloud and fog environments for organizational adoption. While developing the essential linkage between requirements, legal aspects, analyzing techniques and systems to reduce intrusion detection, we recommend the strategies for cloud and fog computing security policies. The paper develops structured guidelines for ways in which organizations can adopt and audit the security of their systems as security is an essential component of their systems and presents an agile current state-of-the-art review of intrusion detection systems and their principles. Functionalities and techniques for developing these defense mechanisms are considered, along with concrete products utilized in operational systems. Finally, we discuss evaluation criteria and open-ended challenges in this area

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

Cloud computing with an emphasis on PaaS and Google app engine

Thesis on cloud with an emphasis on PaaS and Google App Engin

Cloud migration strategy factors and migration processes

Organisaatiot ottavat pilvitekniikoita ja -palveluita käyttöönsä yhä laajemmin. Merkittävä osa pilvipalveluiden kasvusta johtuu nykyisten sovellusten siirtämisestä pilvipalveluun. Olemassa olevien vanhojen sovellusten siirtäminen pilvipalvelualustaan ei ole triviaali tehtävä. Migraatiomenetelmät tehostavat sovellusten siirtoa pilvialustoille ja vähentävät siirrosta aiheutuvia riskejä käyttäen vakioituja prosessimalleja. Keskeinen osa pilvimigraatioprosessia on valita sopivin strategia pilvimigraatiolle useiden vaihtoehtoisten tilanteesta riippuvien vaihtoehtojen joukosta. Migraatiostrategia määrittelee keskeiset migraatioprosessin vaiheet sekä käytettävän pilviarkkitehtuurin sekä palvelumallit. Nykyiset pilven migraatiomenetelmät eivät erityisesti huomioi tai määrittele migraatiostrategian valintaa määrääviä tekijöitä. Migraatiostrategian valinta on kriittinen osa pilvimigraation suunnittelua, johon tyypillisesti osallistuu useita eri organisaatioita ja asiantuntijoita. Tässä opinnäytetyössä esitetään ryhmittely sekä tekijät, jotka ohjaavat pilvimigraatiostrategian valintaa. Tekijät on johdettu nykyisistä pilvimigraatiomenetelmistä ja -prosesseista. Tekijät on validoitu deduktiivisella temaattisella analyysillä käyttäen kvalitatiivisia tapaustutkimuksia ja niistä saatuja haastattelutietoja. Pilvimigraatiostrategioihin vaikuttavien tekijöiden tunnistamisella ja käsittelyllä voidaan parantaa pilvimigraatioiden onnistumista ja tehostaa pilvimigraatioiden suunnittelua.Organizations are adopting cloud technologies at an increasing rate. Significant share of growth of cloud deployments is coming from application migrations to cloud computing. Migrating existing legacy applications to cloud computing platform is not a trivial task. A migration methodology will help migrating applications to cloud more effectively and with lower risk than doing it by trial and error. A part of the cloud migration process is the selection and execution of a migration strategy amongst the possible, situational and commonly used options. The migration strategy defines many of the migration process activities since they depend on cloud architecture and service and deployment models, which are implicitly set by the migration strategy. Many of the existing cloud migration methods don’t specify the factors that lead to migration strategy selection. The migration strategy selection is a critical part of migration planning involving multiple organisations and several individuals. This thesis presents categories of migration strategy factors derived from a cloud migration methodology and process framework review and validates the factors by doing a deductive thematic analysis against qualitative case study interview data. By having a clarity and a way to address the migration strategy factors, will increase the migration success rate and reduce planning time

Reference Framework and Research Agenda

Cloud Computing is a topic that has gained momentum in the last years. Current studies show that an increasing number of companies is evaluating the promised advantages and considering making use of cloud services. In this paper we investigate the phenomenon of cloud computing and its importance for the operation of ERP systems. We argue that the phenomenon of cloud computing could lead to a decisive change in the way business software is deployed in companies. Our reference framework contains three levels (IaaS, PaaS, SaaS) and clarifies the meaning of public, private and hybrid clouds. The three levels of cloud computing and their impact on ERP systems operation are discussed. From the literature we identify areas for future research and propose a research agenda