Tenant Isolation Research Articles

Tenant-Grained Request Scheduling in Software-Defined Cloud Computing

Cloud providers host various services for tenants’ requests (e.g., software-as-a-service) and seek to serve as many requests as possible for revenue maximization. Considering a large number of requests, the previous works on fine-grained request scheduling may lead to poor system scalability (or high schedule overhead) and break tenant isolation. In this article, we design a tenant-grained request scheduling framework to conquer the above two disadvantages. We formulate the tenant-grained request scheduling problem as an integer linear programming and prove its NP-hardness. We consider two complementary cases: the offline case (where we know all request demands in advance), and the online case (where we have to make immediate scheduling decisions for requests arriving online). A normalization-based algorithm with an approximation factor of <inline-formula><tex-math notation="LaTeX">$ {O}(1)$</tex-math></inline-formula> is proposed to solve the offline problem and a primal-dual-based algorithm with a competitive ratio of <inline-formula><tex-math notation="LaTeX">$[(1-\epsilon), {O}(\log 3\cdot n+\log (1/\epsilon))]$</tex-math></inline-formula> is designed for the online scenario, where <inline-formula><tex-math notation="LaTeX">$\epsilon \in (0,1)$</tex-math></inline-formula> and <inline-formula><tex-math notation="LaTeX">$n$</tex-math></inline-formula> is the number of racks in the cloud. We also discuss how to integrate our proposed algorithms with the previous (fine-grained) request scheduling mechanism. Extensive simulation and experiment results show that our algorithms can obtain significant performance gains, e.g., the online algorithm reduces the scheduler's overhead more than <inline-formula><tex-math notation="LaTeX">$90\%$</tex-math></inline-formula> and achieves tenant isolation, while obtaining similar network performance (e.g., throughput) compared with the fine-grained request scheduling methods.

Highly Scalable and Secure Kubernetes Multi Tenancy Architecture for Fintech

The study also presents a Kubernetes multi-tenancy design that is highly scalable and secure for FinTech applications. Kubernetes’ ability to manage the containers well makes it perfect for the financial institutions that need strong infrastructure solutions. Some of the main issues like scalability, security and compliance are targeted in the architecture. For the purpose of tenant isolation it uses mechanisms such as namespaces, network policies, and role-based access control while for dynamic resource allocation and the improved security depth it uses mechanisms like pod security policies. Performance and security analysis shows satisfactory results, which proves that the chosen architecture helps to solve multifaceted FinTech problems with minimal consumption of resources and low expenses

TOSDS: Tenant-centric Object-based Software Defined Storage for Multitenant SaaS Applications.

Enormous amounts of unstructured data such as images, videos, emails, sensors’ data and documents of multiple types are being generated daily by varied applications. Apart from the challenges related to collection or processing of this data, its efficient storage is also a significant challenge since this data do not conform to any predefined storage model. Therefore, any enterprise dealing with huge unstructured data requires a scalable storage system that can provide data durability and availability at a low cost. The paper proposes a tenant-centric approach to develop an object-based software defined storage system for SaaS multi-tenant applications. We present TOSDS (Tenant-centric Object-based Software Defined Storage), a system that can efficiently meet the storage requirements of users or tenants with diverse needs who are using a multitenant SaaS application. The experimental verification of TOSDS illustrates its effectiveness in storage utilization as well as tenant isolation.

Resilient Control Plane Design for Virtual Software Defined Networks

Control plane survivability in virtual software-defined networks (vSDN) – where multiple tenants share the same physical infrastructure – is even more critical than in normal SDN networks. A reliable communication channel from the switches through the network hypervisor to the virtual controller is inevitable in order to avoid state inconsistencies, tenant isolation and security issues on the virtual switches. Although reliable controller placement and control plane design was thoroughly investigated in SDNs, there was a lack of attention for resilient hypervisor placement and control path design for vSDNs. Therefore, in this paper we make a two-fold contribution towards a survivable vSDN control plane. First, we propose an approximation algorithm for (hypervisor) placement which – in contrast with traditional approaches which minimize the average latency to the hypervisors as an objective function – focuses on finding the appropriate number of hypervisor instances to satisfy the control path length constraints declared in the service level agreements, leaving enough options open for self-driving network designs and intelligent algorithms. Second, we propose a general dynamic program that calculates minimum length paths traversing specific type of nodes in a given order, and apply it to find control paths from the virtual controller of the slice to the virtual switches traversing the corresponding hypervisor location. We conduct thorough simulations on real-world topologies to demonstrate the effectiveness of our approaches in no failure and single link failure scenarios.

Design Patterns and Electric Vehicle Charging Software

The development and maintenance of complex software systems, with ever-changing requirements has benefited from the implementation of design patterns, which ensure a higher degree of maintainability. The present article illustrates the essential role of design patterns in sketching the software architecture for an electric vehicle charging management platform. We have integrated a series of design patterns to create a solid base structure for the API (Application Programming Interface). Furthermore, we have explored cloud design patterns in the deployment process to ensure a proper multi-tenant cloud application with the best possible tenant isolation for the cost. The aim of this paper is to offer readers an introduction in the case study theme, to describe a complex platform development through design patterns. With proper examples from real projects debated in the industry. The paper demonstrates the design patterns applicability from software level to cloud resources plan and advocates for a high-quality solution in every segment of project development. In conclusion, the results are promising, and the functionality of the established methods on this type of platforms will be evaluated during the implementation period. Overall, design patterns have proven to be essential in the development process, ensuring effective team communication and the delivery of qualitative software solutions.

CURATE: On-Demand Orchestration of Services for Health Emergencies Prediction and Mitigation

Telemedicine, or the ability granted to doctors to remotely assist patients has been greatly benefited by advances in IoT, network communications, Machine Learning and Edge/Cloud computing. With the impeding arrival of 5G, virtualized infrastructures and cloud-native approaches enable the execution of unprecedented procedures during such patient/doctor interactions, allowing medical professionals to e.g. request higher granularity metrics from patients' telemetry equipment, or perform on-demand data mining/processing of patient's stored data in order to provide a more educated diagnostic or prediction. In this work we coalesce the virtues of virtualized infrastructures and IoT into a solution able to satisfy increasing data processing demands for eHealth, e.g. for telemedicine applications, remote assistance or patient pre-screening procedures. The proposed platform, CURATE, leverages Network Functions Virtualisation Management and Orchestration (NFV MANO) for the on-demand instantiation of the required virtual resources on the operator's infrastructure, as well as the concept of 5G Network Slices to guarantee efficient resource allocation and tenant isolation. Results show the proposed platform is able to efficiently make use of the available hardware resources via Network Slices, as well as provide cost-effective service guarantees employing dynamic scaling operations.

Links as a Service (LaaS): Guaranteed Tenant Isolation in the Shared Cloud

The most demanding tenants of shared clouds require complete isolation from their neighbors, in order to guarantee that their application performance is not affected by other tenants. Unfortunately, while shared clouds can offer an option, whereby tenants obtain dedicated servers, they do not offer any network provisioning service, which would shield these tenants from network interference. In this paper, we introduce links as a service (LaaS), a new abstraction for cloud service that provides isolation of network links. Each tenant gets an exclusive set of links forming a virtual fat-tree, and is guaranteed to receive the exact same bandwidth and delay as if it were alone in the shared cloud. Consequently, each tenant can use the forwarding method that best fits its application. Under simple assumptions, using bipartite graph properties and pigeonhole-based analysis, we derive theoretical conditions for enabling the LaaS without capacity over-provisioning in fat-trees. New tenants are only admitted in the network, when they can be allocated hosts and links that maintain these conditions. We also provide new results on the numbers of tenants and hosts that can fit while guaranteeing network isolation. The LaaS is implementable with common network gear, tested to scale to large networks, and provides full tenant isolation at the cost of a limited reduction in the cloud utilization.

Degrees of tenant isolation for cloud-hosted software services: a cross-case analysis

A challenge, when implementing multi-tenancy in a cloud-hosted software service, is how to ensure that the performance and resource consumption of one tenant does not adversely affect other tenants. Software designers and architects must achieve an optimal degree of tenant isolation for their chosen application requirements. The objective of this research is to reveal the trade-offs, commonalities, and differences to be considered when implementing the required degree of tenant isolation. This research uses a cross-case analysis of selected open source cloud-hosted software engineering tools to empirically evaluate varying degrees of isolation between tenants. Our research reveals five commonalities across the case studies: disk space reduction, use of locking, low cloud resource consumption, customization and use of plug-in architecture, and choice of multi-tenancy pattern. Two of these common factors compromise tenant isolation. The degree of isolation is reduced when there is no strategy to reduce disk space and customization and plug-in architecture is not adopted. In contrast, the degree of isolation improves when careful consideration is given to how to handle a high workload, locking of data and processes is used to prevent clashes between multiple tenants and selection of appropriate multi-tenancy pattern. The research also revealed five case study differences: size of generated data, cloud resource consumption, sensitivity to workload changes, the effect of the software process, client latency and bandwidth, and type of software process. The degree of isolation is impaired, in our results, by the large size of generated data, high resource consumption by certain software processes, high or fluctuating workload, low client latency, and bandwidth when transferring multiple files between repositories. Additionally, this research provides a novel explanatory framework for (i) mapping tenant isolation to different software development processes, cloud resources and layers of the cloud stack; and (ii) explaining the different trade-offs to consider affecting tenant isolation (i.e. resource sharing, the number of users/requests, customizability, the size of generated data, the scope of control of the cloud application stack and business constraints) when implementing multi-tenant cloud-hosted software services. This research suggests that software architects have to pay attention to the trade-offs, commonalities, and differences we identify to achieve their degree of tenant isolation requirements.

POSENS: A Practical Open Source Solution for End-to-End Network Slicing

Network slicing represents a new paradigm to operate mobile networks. With network slicing, the underlying infrastructure is sliced into logically separate networks that can be customized to the specific needs of their tenant. Hands-on experiments on this technology are essential to understand its benefits and limits, and to validate the design and deployment choices. While some network slicing prototypes have been built for RANs, leveraging on the wide availability of radio hardware and open source software, there is currently no open source suite for end-to-end network slicing available to the research community. In this article we fill this gap by developing an end-to-end network slicing protocol stack, POSENS, which relies on a slice-aware shared RAN solution. We design the required algorithms and protocols, and provide a full implementation leveraging on state-of-the-art software components. We validate the effectiveness of POSENS in achieving tenant isolation and network slices customization, showing that no price in performance is paid toward this end. We believe that our tool will prove very useful to researchers and practitioners working on this novel architectural paradigm.

MT-DIPS: a new data duplication integrity protection scheme for multi-tenants sharing storage in SaaS

In SaaS, the data sharing storage mode and tenant isolation requirement present new challenge to traditional remote data duplication protection schemes. This paper aims at the new requirement of tenant data duplication protection in SaaS and presents a tuple sampling-based tenant duplication protection mechanism MT-DIPS (Duplication Integrity Protection Scheme for Multi-Tenants). Instead of data block sampling, MT-DIPS accommodates the data isolation requirement of different tenants by sampling tenants physical data tuples. Through periodical random sampling, MT-DIPS reduces the complexity on service provider side of verification object construction and eliminates the resource waste. Analysis and the experimental results show that if the damage rate of tenant data tuples is about 1%, the random sampling data number is about 5% of the total number of tuples. MT-DIPS makes use of homomorphism labels with auxiliary authentication structure to allow trusted third party verification without disclosing tenant data to relieve the verification burden on tenants' client sides.

MT-DIPS: a new data duplication integrity protection scheme for multi-tenants sharing storage in SaaS

In SaaS, the data sharing storage mode and tenant isolation requirement present new challenge to traditional remote data duplication protection schemes. This paper aims at the new requirement of tenant data duplication protection in SaaS and presents a tuple sampling-based tenant duplication protection mechanism MT-DIPS (Duplication Integrity Protection Scheme for Multi-Tenants). Instead of data block sampling, MT-DIPS accommodates the data isolation requirement of different tenants by sampling tenants physical data tuples. Through periodical random sampling, MT-DIPS reduces the complexity on service provider side of verification object construction and eliminates the resource waste. Analysis and the experimental results show that if the damage rate of tenant data tuples is about 1%, the random sampling data number is about 5% of the total number of tuples. MT-DIPS makes use of homomorphism labels with auxiliary authentication structure to allow trusted third party verification without disclosing tenant data to relieve the verification burden on tenants' client sides.

A 4D-Role Based Access Control Model for Multitenancy Cloud Platform

Since more and more applications and services have been transferred from servers in the B/S architecture to cloud, user access control has become a significant part in a multitenancy cloud platform. Role based access control model makes users participate in an enterprise system as particular identities. However, in a multitenancy cloud environment, it has a high probability that the information of tenants has been leaked by using existing role based access control (RBAC) model. Moreover, management problems may emerge in the multitenancy platform with the increment of the number of tenants. In this paper, a novel concept of 4D-role is presented. With a detailed definition on the concept of 4D-role, a 4D-role based multitenancy model is proposed for running various applications and services in the multitenancy cloud platform. A theoretical analysis indicates that the model has the characters of tenant isolation, role hierarchy, and administration independence. The three characters are also verified by experimental evaluation. Moreover, the evaluation results indicate that the model has a good performance in using cloud resources when large-scale users are operating in the cloud platform simultaneously.

Jointly optimized QoS-aware virtualization and routing in software defined networks

Software Defined Networks (SDNs) have been recognized as the next-generation networking paradigm that decouples the network control plane from the data forwarding plane. A logically centralized controller is responsible for all the control decisions and communication among the forwarding switches. However, current traffic engineering techniques and state-of-the-art routing algorithms do not effectively use the merits of SDNs, such as global centralized visibility, control and data plane decoupling, network management simplification and great computation capability. In this paper, a multi-tenancy management framework is proposed to enable the jointly optimized design of quality-of-services (QoSs)-aware virtualization and routing by tenant isolation and prioritization as well as flow allocation, fulfilling QoS requirements of tenants’ applications. Specifically, a fine-grained network virtualization is first proposed to isolate and prioritize tenants through the design of network and switch hypervisors. Furthermore, a QoS-aware dynamic flow allocation is proposed to enable optimal flow routes selection upon the given network slicing with QoS provisioning. Finally, an adaptive feedback management tool, called QoS-aware Virtualization-enabled Routing (QVR), is proposed to combine virtualization with flow allocation and supports reliable and efficient transmissions with regards of time-varying QoS requirements, network topologies, and traffic statistics. Simulations confirm that QVR achieves much less shared edges, congestion latency, and traffic delay for multiple tenants, thus facilitating virtualization-enabled traffic engineering for multi-tenancy SDNs.

Evaluating Degrees of Isolation between Tenants enabled by Multitenancy Patterns for Cloud-hosted Version Control Systems (VCS)

When implementing multitenancy for cloud-hosted applications, one of the main challenges to overcome is how to enable the required degree of isolation between tenants so that the required performance, resource utilization, and access privileges of one tenant does not affect other tenants. This paper applies COMITRE (COmponent-based approach to Multitenancy Isolation Through request RE-routing) to empirically evaluate the degree of isolation between tenants enabled by multitenancy patterns for cloud-hosted Version Control System (VCS). We implemented three multitenancy patterns (i.e., shared component, tenant-isolated component, and dedicated component) by developing a multitenant component using the FileSystem SCM plugin integrated within Hudson. The study confirmed that dedicated component provides the highest degree of isolation between tenants (compared to shared component and tenant-isolated component) in terms of error% (i.e., the percentage oferrors with unacceptably slow response times) and throughput. The system load of tenants showed no variability, and hence did not influence the degree of tenant isolation for all the three multitenancy patterns. We also provide a summary of recommended multitenancy patterns for optimizing performance and utilization of resources for cloud-hosted software services, as well as recommendations to guide an architect in implementing multitenancy isolation on similar VCS tools like Subversion and CVS.

IEEE Access Special Section Editorial: Recent Advances in Software Defined Networking for 5G Networks

The demand for flexible network management has been growing significantly over the last several decades, which comes with a series of other related demands in network virtualization, stringent security, tenant isolation in cloud, and high performance and reliability for broadband access. To meet these demands from both users and enterprises, numerous networking protocols had been designed and developed. However, these protocols were usually defined independently targeting various specific problems using different systems and sub-systems, without a holistic approach. On the other hand, cloud computing brings many challenges to traditional networking, from naming and addressing to the traditional routing. In addition, companies seek to use more standard and vendor-independent equipment to reduce the Capital Expenditure (CAPEX) and Operational Expenditure (OPEX).