5G network slicing using SDN and NFV: A survey of taxonomy, architectures and future challenges

This paper suggests how the ‘grey literature’, the diverse and heterogeneous body of material that is made public outside, and not subject to, traditional academic peer-review processes, can be used to increase the relevance and impact of management and organization studies (MOS). The authors clarify the possibilities by reviewing 140 systematic reviews published in academic and practitioner outlets to answer the following three questions: (i) Why is grey literature excluded from/included in systematic reviews in MOS? (ii) What types of grey material have been included in systematic reviews since guidelines for practice were first established in this discipline? (iii) How is the grey literature treated currently to advance management and organization scholarship and knowledge? This investigation updates previous guidelines for more inclusive systematic reviews that respond to criticisms of current review practices and the needs of evidence-based management.

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Shades of Grey: guidelines for working with the grey literature in systematic reviews for management and organizational studies

Fog computing aims at extending the Cloud by bringing computational power, storage, and communication capabilities to the edge of the network, in support of the IoT. Segmentation, distribution, and adaptive deployment of functionalities over the continuum from Things to Cloud are challenging tasks, due to the intrinsic heterogeneity, hierarchical structure, and very large scale infrastructure they will have to exploit. In this paper, we propose a simple, yet general, model to support the QoS-aware deployment of multicomponent IoT applications to Fog infrastructures. The model describes operational systemic qualities of the available infrastructure (latency and bandwidth), interactions among software components and Things, and business policies. Algorithms to determine eligible deployments for an application to a Fog infrastructure are presented. A Java tool, FogTorch , based on the proposed model has been prototyped.

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QoS-Aware Deployment of IoT Applications Through the Fog

Software testing is any activity aimed at evaluating an attribute or capability of a program or system and determining that it meets its required results. Although crucial to software quality and widely deployed by programmers and testers, software testing still remains an art, due to limited understanding of the principles of software. The difficulty in software testing stems from the complexity of software: we can not completely test a program with moderate complexity. Testing is more than just debugging. The purpose of testing can be quality assurance, verification and validation, or reliability estimation. Testing can be used as a generic metric as well. Correctness testing and reliability testing are two major areas of testing. Software testing is a trade-off between budget, time and quality.

Software testing

Containers as a lightweight technology to virtualise applications have recently been successful, particularly to manage applications in the cloud. Often, the management of clusters of containers becomes essential and the orchestration of the construction and deployment becomes a central problem. This emerging topic has been taken up by researchers, but there is currently no secondary study to consolidate this research. We aim to identify, taxonomically classify and systematically compare the existing research body on containers and their orchestration and specifically the application of this technology in the cloud. We have conducted a systematic mapping study of 46 selected studies. We classified and compared the selected studies based on a characterisation framework. This results in a discussion of agreed and emerging concerns in the container orchestration space, positioning it within the cloud context, but also moving it closer to current concerns in cloud platforms, microservices and continuous development.

Cloud Container Technologies: A State-of-the-Art Review

Determining the root causes of observed failures is a main issue in microservice-based applications. Unfortunately, available root cause analysis techniques do not focus on explaining how root failures actually caused the observed failure. On the other hand, the availability of such explanations would greatly help to pick adequate countermeasures, e.g., by introducing circuit breakers or bulkheads. We hence present a declarative root cause analysis technique, which can determine the cascading failures that possibly caused an observed failure, identifying also (or starting from) a root cause. We also introduce a prototype implementation of our technique, and we use it to assess our technique by means of controlled experiments. 

Failure Root Cause Analysis for Microservices, Explained

Modern enterprise applications integrate various heterogeneous components, which management has to be suitably coordinated. Being able to check whether the management allowed by the implementation of an application component conforms to a given specification hence becomes crucial. One may indeed wish to replace component specifications with conforming implementations, by ensuring that already planned management can be enacted, or that no additional (potentially undesired) management activities get enabled. In this perspective, we propose a parametric relation for testing the conformance of the management of application components, based on an existing formalism to model multi-component application management (i.e., management protocols). We also discuss how such relation can be exploited to ensure that replacing a specification with a conforming implementation continues to enable all already allowed management activities, and/or that no additional (potentially undesired) management activity gets enabled.

Testing Conformance in Multi-component Enterprise Application Management

Fault-aware management protocols permit modelling the management of application components (including potential faults) and analysing the management behaviour of a multi-component application The analysis is driven by the application topology, and it assumes many-to-1 dependencies among application components, ie each requirement of a component can be satisfied by exactly one other component

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Modelling the Dynamic Reconfiguration of Application Topologies, Faults Included

Modern enterprise applications integrate multiple interdependent software components, whose management must be suitably coordinated. This must be done by taking into account all inter-component dependencies, the faults potentially affecting them, and the fact that each component can be horizontally scaled, i.e., that multiple instances of each component can be spawned or destroyed, depending on application needs. In this article, we introduce a novel solution for suitably modelling and analysing the replica- and fault-aware management of multi-component applications, based on topology graphs and management protocols. More precisely, we first introduce a compositional model of the management behaviour of the (possibly multiple) instances of the components forming an application, faults included. We then show how this model enables automating various useful analyses, from checking the validity of management plans to automatically determining management plans allowing the instance of an application to reach and maintain a desired target configuration.

Modelling and Analysing Replica- and Fault-aware Management of Horizontally Scalable Applications

Trans-cloud applications consist of multiple interacting components deployed across different cloud providers and at different service layers (IaaS and PaaS). In such complex deployment scenarios, fault handling and recovery need to deal with heterogeneous cloud offerings and to take into account inter-component dependencies. We propose a methodology for self-healing trans-cloud applications from failures occurring in application components or in the cloud services hosting them, both during deployment and while they are being operated. The proposed methodology enables reducing the time application components rely on faulted services, hence residing in “unstable” states where they can suddenly fail in cascade or exhibit erroneous behaviour. We also present an open-source prototype illustrating the feasibility of our proposal, which we have exploited to carry out an extensive evaluation based on controlled experiments and monkey testing.

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Jacopo Soldani

Papers

Failure Root Cause Analysis for Microservices, Explained

Testing Conformance in Multi-component Enterprise Application Management

Modelling the Dynamic Reconfiguration of Application Topologies, Faults Included

Modelling and Analysing Replica- and Fault-aware Management of Horizontally Scalable Applications

Self-healing trans-cloud applications