SLA Guarantees Research Articles

Securing Service Instantiation on Next-generation Networks

The Next Generation of Software Defined Networks (NG-SDN) enables a whole new set of possibilities for innovation in the data plane (e.g., computing, monitoring, load-balancing). In parallel, we have been witnessing the increasing adoption of virtualized services running in light but efficient containers, which brings forth the capability to flexibly deploy services at the network edge, while providing dynamic scaling and management. As a result, operators have tap in a lot of computational real-estate as part of the adoption of telco cloud concepts, as well as to support the foreseen edge and fog computing scenarios. However, exposing the infrastructure to third parties and realizing complex services over a multi-stakeholder environment raises challenges at different levels (e.g., security, reliability, SLA guarantees). Reconfiguring the data plane for flow monitoring and handling service requests directly on the data plane could address these challenges to support the joint communication and computation vision. This is where this paper contributes by proposing a secure and reliable system for dynamic instantiation of third-party services. A proof-of-concept prototype was developed using P4 and Kubernetes showcasing the feasibility of the proposed approach.

Apriori Algorithm Based Approach for Improving QoS and SLA Guarantee in IaaS Clouds Using Pattern-Based Service-Oriented Architecture

Apriori Algorithm Based Approach for Improving QoS and SLA Guarantee in IaaS Clouds Using Pattern-Based Service-Oriented Architecture

Make Rental Reliable: Blockchain-Based Network Slice Management Framework with SLA Guarantee

Make Rental Reliable: Blockchain-Based Network Slice Management Framework with SLA Guarantee

HiTDL: High-Throughput Deep Learning Inference at the Hybrid Mobile Edge

Deep neural networks (DNNs) have become a critical component for inference in modern mobile applications, but the efficient provisioning of DNNs is non-trivial. Existing mobile- and server-based approaches compromise either the inference accuracy or latency. Instead, a hybrid approach can reap the benefits of the two by splitting the DNN at an appropriate layer and running the two parts separately on the mobile and the server respectively. Nevertheless, the DNN throughput in the hybrid approach has not been carefully examined, which is particularly important for edge servers where limited compute resources are shared among multiple DNNs. This article presents HiTDL, a runtime framework for managing multiple DNNs provisioned following the hybrid approach at the edge. HiTDL's mission is to improve edge resource efficiency by optimizing the combined throughput of all co-located DNNs, while still guaranteeing their SLAs. To this end, HiTDL first builds comprehensive performance models for DNN inference latency and throughout with respect to multiple factors including resource availability, DNN partition plan, and cross-DNN interference. HiTDL then uses these models to generate a set of candidate partition plans with SLA guarantees for each DNN. Finally, HiTDL makes global throughput-optimal resource allocation decisions by selecting partition plans from the candidate set for each DNN via solving a fairness-aware multiple-choice knapsack problem. Experimental results based on a prototype implementation show that HiTDL improves the overall throughput of the edge by <inline-formula><tex-math notation="LaTeX">$4.3\times$</tex-math></inline-formula> compared with the state-of-the-art.

SCOPE: self-adaptive and policy-based data management middleware for federated clouds

A federated cloud storage setup which integrates and utilizes storage resources from multiple cloud storage providers has become an increasingly popular and attractive paradigm for the persistence tier in cloud-based applications (e.g., SaaS applications, IoT applications, etc).However, federated cloud storage setups are prone to run-time dynamicity: many dynamic properties impact the way such a setup is governed and evolved over time, e.g., storage providers enter or leave the market; QoS metrics and SLA guarantees may change over time; etc. In general, existing federated cloud systems are oblivious to dynamic properties of the underlying operational environment, resulting in both sub-optimal data management decisions and costly SLA violations. Additionally, due to the sheer complexity of cloud-based applications coupled with the heterogeneous and volatile nature of federated cloud setups, the complexity of building, maintaining, and expending such applications increases dramatically and therefore managing them manually is no longer simply an option.To address these concerns, we present SCOPE, a policy-based and autonomic middleware that provides self-adaptiveness for data management in federated clouds. We have validated SCOPE in the context of a realistic SaaS application, performed an extensive functional validation, and conducted a thorough experimental evaluation. The evaluation results demonstrate (i) the ability of the middleware to perform data management decisions that take into account the run-time dynamicity (i.e., dynamic properties) of a federated cloud storage setup to meet the promised SLAs, and (ii) the self-adaptive behavior of SCOPE without the need for operator intervention. In addition, our in-depth performance evaluation results indicate that the benefits are achieved with acceptable performance overhead, and as such highlight the applicability of the proposed middleware for real-world application cases.

A Blockchain-based Model for Cloud Service Quality Monitoring

This paper introduces a novel blockchain-based decentralized federation model that embodies quality verification for cloud providers who lease computing resources from each other. The blockchain structure removes the barriers of a traditional centralized federation and offers a fully distributed and transparent administration by enforcing the involved agents to maintain consensus on the data. For a blockchain-based federation, it is vital to avoid blind-trust on the claimed SLA guarantees and monitor the quality of service which is highly desirable considering the multi-tenancy characteristic of cloud services. Due to the fact that the blockchain network is unable to access the outside world, it cannot handle, by its own, providers misbehavior in terms of SLA violations. Thus, we introduce oracle as a verifier agent to monitor the quality of the service and report to the smart contract agents deployed on the blockchain. Oracle is a trusted third-party agent who can communicate with the outside world of the blockchain network. The interaction between cloud service providers (either providing a service or requesting it from another provider) and the oracle through smart contracts comprises a system of autonomous and utility maximizer agents. Cloud requesters seek to receive high quality services with constant monitoring at cheap prices or even with no charge, while cloud providers aim to have a balanced work-load with less preserved capacity, and the oracle tends to charge higher for their monitoring services. Therefore, to model this conflicting situation, we formulate a dynamic Stackelberg differential game to optimize the cost of using the oracle and maximize the profit of the agents with the role of provider agent as a leader, and the requester and verifier agents as followers. Our designed Stackelberg differential game can seize the dynamicity of users’ demand and resource provisioning in a competitive cloud market. We implemented our proposed decentralized model using the Solidity language in the remix IDE on the Ethereum network. We further evaluated the optimal controls and agents’ profit with real-world data simulated for three concrete cloud providers. The results revealed that the requester agent initiates most of the quality verification requests at the beginning to the middle time of the contract. Thus, the provider agent could reserve less computing resources considering the fact that it could share the workload among other customers’ computing resources during the peak-time. Moreover, imposing a higher penalty on the provider agent increased the capacity and decreased the number of requests for quality verification at the equilibrium. The evaluation also disclosed that the impact of timing in the dynamic pricing strategy of the verifier agent is very minimal, and the provisioning capacity of the provider is strongly correlated with the monitoring price.

Correction: HBPF: a Home Blood Pressure Framework with SLA guarantees to follow up hypertensive patients

Correction: HBPF: a Home Blood Pressure Framework with SLA guarantees to follow up hypertensive patients

HBPF: a Home Blood Pressure Framework with SLA guarantees to follow up hypertensive patients

Hypertension or high blood pressure is a condition on the rise. Not only does it affect the elderly but is also increasingly spreading to younger sectors of the population. Treating it involves exhaustive monitoring of patients. A tool adapted to the particular requirements of hypertension can greatly facilitate monitoring and diagnosis. This paper presents HBPF, an efficient cloud-based Home Blood Pressure Framework. This allows hypertensive patients to communicate with their health-care centers, thus facilitating monitoring for both patients and clinicians. HBPF provides a complete, efficient, and cross-platform framework to follow up hypertensive patients with an SLA guarantee. Response time below one second for 80,000 requests and 28% increase in peak throughput going from one to three virtual machines were obtained. In addition, a mobile app (BP) for Android and iOS with a user-friendly interface is also provided to facilitate following up hypertensive patients. Among them, between 54% and 87% favorably evaluated the tool. BP can be downloaded for free from the website Hesoft Group repository (http://www.hesoftgroup.eu).

Energy-Efficient SLA Guarantees for Virtualized GPU in Cloud Gaming

Both power consumption and SLA guarantees are important concerns for cloud gaming. Recently, various approaches have been developed to effectively reduce GPU power consumption by making GPU run at low frequencies. However, virtual machines (VMs) running on the same physical GPU with virtualization technology are correlated, because the change of GPU frequencies will affect the SLA performance of all the VMs. In fact, both reducing power consumption and guaranteeing SLA should work together under the considerations of their correlations. This paper proposes a novel two-layer control architecture called energy-efficient SLA guarantees for virtualized GPU (EvGPU) based on well-established feedback control techniques. The first control loop adopts a proportional-integral (PI) controller to ensure SLA guarantees, which in particular are measured at a predefined level of the frames per second (FPS) for each online game. The secondary power control loop then adjusts GPU frequency through dynamic voltage/frequency scaling (DVFS) to reduce power consumption based on the current FPS achieved by the first loop. Empirical results demonstrate that the proposed solution can effectively reduce GPU power consumption, while achieving the required SLA performance in virtualized GPU for cloud gaming.

클라우드 서비스의 품질 중요도 인식에 대한 연구

Although there are usual security threats caused by the characteristics of cloud services, more public institutions plan to introduce the cloud services rapidly, as the increase of recognition for its advantage. The previous studies have focused on the security threats and the quality as a hindrance of activation of cloud services. Those also have stressed the importance of the quality in the cloud user side. But there was no consideration about which quality factors impact on the satisfaction of users. Therefore, this study analyzed the importances of quality in specific five major factors. The results also presented that the SLA guarantee is more important than the security performance. This research will contribute to cloud services providers in Korea, by aiding the establishment of effective quality strategies.

SLA guarantees for cloud services

Quality-of-service and SLA guarantees are among the major challenges of cloud-based services. In this paper we first present a new cloud model called SLAaaS — SLA aware Service. SLAaaS considers QoS levels and SLA as first class citizens of cloud-based services. This model is orthogonal to other SaaS, PaaS, and IaaS cloud models, and may apply to any of them. More specifically we make three contributions: (i) we provide a novel domain specific language that allows to describe QoS-oriented SLA associated with cloud services; (ii) we present a general control-theoretic approach for managing cloud service SLA; (iii) we apply the proposed language and control approach to guarantee SLA in various case studies, ranging from cloud-based MapReduce service, to locking service, and higher-level e-commerce service; these case studies successfully illustrate SLA management with different QoS aspects of cloud services such as performance, dependability, financial energetic costs.