New paper “Energy-efficient microservice-based software architectures in cloud environments”
Energy-efficient microservice-based software architectures in cloud environments
by César Perdigão Batista, Sophie Chabridon, Denis Conan
Abstract
Cloud servers face growing energy demands, imposing operational costs and challenges for sustainability goals. The proliferation of microservice architectures presents opportunities for energy management, offering modularity and scalability. However, microservices may introduce energy inefficiencies due to excessive inter-service communication and mismanaged scaling. Existing solutions commonly focus on hardware-level optimization, overlooking application-level energy consumption. This research aims to integrate energy metrics into the lifecycle of microservice-based applications to enable energy-aware decision-making. Using the MAPE-K framework, we enhance Monitoring, Analysis, and Knowledge components with energy metrics. Contributions include runtime monitoring tooling, energy-aware distributed tracing, and reconfiguration strategies, with initial results validated using the TeaStore benchmark application deployed on Grid’5000 testbed. The research will deliver tools and strategies for improving energy efficiency in microservice-based applications, benefiting cloud providers, architects, and end-users striving for sustainable operations.
New paper “Achieving Energy Efficiency in Microservice-Based Cloud Applications: A Systematic Study”
Achieving Energy Efficiency in Microservice-Based Cloud Applications: A Systematic Study
by César Perdigão Batista, Glauber Barros, Thais Batista, Sophie Chabridon and Denis Conan
Abstract
The growth of Cloud computing has enabled scalable and accessible services, while also intensifying concerns over energy consumption, carbon emissions, and both the environmental and financial sustainability of data centers. Microservice architectures offer promising opportunities for granular resource optimization and energy savings, though it can also introduce complexities. It is crucial to investigate how microservice-based Cloud applications address energy efficiency. For this purpose, we conducted a systematic literature review (SLR) aiming to establish an overview of the state-of-the-art on energy-efficient microservice-based Cloud applications. The research questions of the SLR focus on revealing: (i) strategies to mitigate energy inefficiencies in microservice-based Cloud applications; (ii) experimental methodologies used to assess the effectiveness of the proposed strategy, and (iii) mechanisms for measuring energy consumption. As a result, 25 studies were selected and synthesized to provide a comprehensive overview about the topic. This paper also presents a taxonomy and raises important challenges and potential directions for future research.
New paper “Process mining approach for multi-cloud SLA reporting” at IEEE Big Data 2023
Authors: Jeremy Mechouche, Mohamed Sellami, Zakaria Maamar, Roua Touihri, and Walid Gaaloul
Abstract
Cloud consumers’ requirements possess an inherent dynamic nature, characterized by fluctuating needs in reliability and high-availability relative to their workload. To satisfy these requirements, service reconfiguration strategies are put in place ensuring first, adaptable service provisioning and second, compliance with the agreed-upon Service Level Agreements (SLAs) between consumers and providers. However, deviations between SLAs and “real” observed behaviours could occur even after triggering reconfiguration strategies. Additionally, as organizations increasingly embrace multi-cloud environments, careful consideration must be given to the inherent challenges that arise in this requirements satisfaction. In this paper, we represent these strategies as state machines used to report their conformance to collected logs which track what really happened at run-time. The collected logs are processed to construct state machines suitable for conformance checking. Experiments demonstrating the technical doability of using conformance checking to detect deviations between SLAs and logs, along with verifying the suitability of reconfiguration strategies, are also discussed in the paper.
New paper “Bringing privacy, security and performance to the Internet of Things using IOTA and usage control”
Bringing privacy, security and performance to the Internet of Things using IOTA and usage control
by Nathanaël Denis, Sophie Chabridon and Maryline Laurent
Abstract
The Internet of Things (IoT) is bringing new ways to collect and analyze data to develop applications answering or anticipating users’ needs. These data may be privacy-sensitive, requiring ecient privacypreserving mechanisms. The IoT is a distributed system of unprecedented scale, creating challenges for performance and security. Classic blockchains could be a solution by providing decentralization and strong security guarantees. However, they are not ecient and scalable enough for large scale IoT systems, and available tools designed for preserving privacy in blockchains, e.g. coin mixing, have a limited eect due to high transaction costs and insucient transaction rates. This article provides a framework based on several technologies to address the requirements of privacy, security and performance of the Internet of Things. The basis of the framework is the IOTA technology, a derivative of blockchains relying on a directed acyclic graph to create transactions instead of a linear chain. IOTA improves distributed ledger performance by increasing transaction throughput as more users join the network, making the network scalable. As IOTA is not designed for privacy protection, we complement it with privacy-preserving mechanisms: merge avoidance and decentralized mixing. Finally, privacy is reinforced by introducing usage control mechanisms for users to monitor the use and dissemination of their data. A Proof of Concept is proposed to demonstrate the feasibility of the proposed framework. Performance tests are conducted on this Proof of Concept, showing the framework can work on resource-constrained devices and within a reasonable time. The originality of this contribution is also to integrate an IOTA node within the usage control system, to support privacy as close as possible to the objects that need it.
New paper “Integrating Usage Control Into Distributed Ledger Technology for Internet of Things Privacy”
Integrating Usage Control Into Distributed Ledger Technology for Internet of Things Privacy
by Nathanaël Denis, Maryline Laurent and Sophie Chabridon
IEEE Internet of Things Journal, Volume: 10, Issue: 22, jun. 2023
Abstract
The Internet of Things (IoT) brings new ways to collect privacy-sensitive data from billions of devices. Well-tailored distributed ledger technologies (DLTs) can provide high transaction processing capacities to IoT devices in a decentralized fashion. However, privacy aspects are often neglected or unsatisfying, with a focus mainly on performance and security. In this article, we introduce decentralized usage control mechanisms to empower IoT devices to control the data they generate. Usage control defines obligations, i.e., actions to be fulfilled to be granted access, and conditions on the system in addition to data dissemination control. The originality of this article is to consider the usage control system as a component of distributed ledger networks, instead of an external tool. With this integration, both technologies work in synergy, benefiting their privacy, security, and performance. We evaluated the performance improvements of integration using the IOTA technology, particularly suitable due to the participation of small devices in the consensus. The results of the tests on a private network show an approximate 90% decrease of the time needed for the usage control system to push a transaction and make its access decision in the integrated setting, regardless of the number of nodes in the network.
Best paper “SmartSPEC: Customizable Smart Space Datasets via Event-Driven Simulations” at PERCOM 2022
Authors: Andrew Chio, Daokun Jiang, Peeyush Gupta, Georgios Bouloukakis, Roberto Yus, Sharad Mehrotra and Nalini Venkatasubramanian
Mark Weiser Best Paper Award (sponsored by Elsevier Pervasive and Mobile Computing)
Artifacts
Abstract
This paper presents SmartSPEC, an approach to generate customizable smart space datasets using sensorized spaces in which people and events are embedded. Smart space datasets are critical to design, deploy and evaluate robust systems and applications to ensure cost-effective operation and safety/comfort/convenience of the space occupants. Often, real-world data is difficult to obtain due to the lack of fine-grained sensing; privacy/security concerns prevent the release and sharing of individual and spatial data. SmartSPEC is a smart space simulator and data generator that can create a digital representation (twin) of a smart space and its activities. SmartSPEC uses a semantic model and ML-based approaches to characterize and learn attributes in a sensorized space, and applies an event-driven simulation strategy to generate realistic simulated data about the space (events, trajectories, sensor datasets, etc). To evaluate the realism of the data generated by SmartSPEC, we develop a structured methodology and metrics to assess various aspects of smart space datasets, including trajectories of people and occupancy of spaces. Our experimental study looks at two real-world settings/datasets: an instrumented smart campus building and a city-wide GPS dataset. Our results show that the trajectories produced by SmartSPEC are 1.4x to 4.4x more realistic than the best synthetic data baseline when compared to real-world data, depending on the scenario and configuration.
Keywords: smart space, sensor, simulation, trajectory
New paper “Analysis of the Impact of Interaction Patterns and IoT Protocols on Energy Consumption of IoT Consumer Applications” at DAIS 2022
Authors: Rodrigo Canek, Pedro Borges, and Chantal Taconet
Abstract
Nowadays, it is estimated that half the connected devices are related to the Internet of Things (IoT). The IoT paradigm contributes to the increase of the Information Technology energy demand. The energy demand is due on one side to the huge number of IoT devices, and on the other side to the plethora of IoT end user applications consuming
data produced by those devices. However, taking into account energy consumption in the development of such applications, consuming data produced by IoT devices is still challenging. There is a lack of knowledge on what are the best practises to develop green IoT applications. The work presented in this paper aims to raise the awareness of application designers concerning the impact of the choice of IoT protocols and interaction patterns on the energy consumption of the applications. For this purpose, we have experimentally analysed the energy consumption of HTTP and MQTT, which are two of the most popular, mature and stable protocols for IoT consumer applications. For the HTTP protocol, we have studied both the publish-subscribe and the request-reply interaction patterns. For MQTT, we have studied the publish-subscribe interaction pattern with the three available Quality of Services. We also examine the impact of message payload on energy consumption. The results show that the publish/subscribe interaction pattern has lower energy consumption (around 92% less) than the synchronous interaction pattern and HTTP consumes 20% more energy than the MQTT protocol for the publish/subscribe interaction pattern. Finally, we have shown that the payload has a low impact on energy consumption having a 9% overhead on payloads ranging from 24 to 3120 bytes
Keywords: Middleware, Internet of Things applications, IoT protocols Interaction patterns, IoT Platforms, Energy Consumption, Green IT
New paper “Conformance checking for autonomous multi-cloud SLA management and adaptation” at Journal of Supercomputing
Authors: Jeremy Mechouche, Roua Touihri, Mohamed Sellami and Walid Gaaloul
Link: https://link.springer.com/article/10.1007/s11227-022-04363-0
Abstract
Satisfying cloud customers’ requirements, i.e., respecting an agreed-on service level agreement (SLA), is not a trivial task in a multi-cloud context. This is mainly due to divergent SLA objectives among the involved cloud service providers and hence divergent reconfiguration strategies to enforce them. In this paper, we propose a hierarchical representation of multi-cloud SLAs: sub-SLAs associated with a system’s components deployed on distinct cloud service providers and global-SLA associated with the whole system. We also enrich these SLA representations with state machines reflecting reconfiguration strategies defined by cloud customers. Then, we propose an autonomous multi-cloud resource orchestrator based on the MAPE-K adaptation control loop to enforce them and to avoid SLA violations. Finally, in order to check the conformity of this enforcement with defined multi-cloud SLA, we propose an approach for multi-cloud SLA reporting inspired by conformance checking techniques. An implementation of the approach is presented in the paper and illustrates the approach feasibility.
New paper “Towards higher-level description of SLA-aware reconfiguration strategies based on state-machine” at ICEBE’2021
Authors: Jeremy Mechouche, Roua Touihri, Mohamed Sellami and Walid Gaaloul
Abstract
High number of European projects and international initiatives show an increased interest in the multi-cloud paradigm. One key need identified in these studies is an SLA-driven service model for multi-cloud environment. While offering a multi-cloud application, cloud consumer define reconfiguration strategies to avoid violating SLAs established with their customers. In this context, this paper presents an approach for enriching multi-cloud SLA representations with reconfiguration strategies. Advantages of this approach are twofold: (i) simplify SLA administration and (ii) limit SLA violations caused by reconfiguration strategies. We represent reconfiguration strategies based on state-machine formalism. Furthermore, we define thresholds to guarantee their compliance with multi-cloud SLAs and anticipate SLA violations. An implementation of the approach is presented in the paper and illustrates how these thresholds are computed.
New paper “Runtime models and evolution graphs for the version management of microservice architectures” at APSEC 2021
Authors: Yuwei Wang, Denis Conan, Sophie Chabridon, Kavoos Bojnourdi, Jingxuan Ma.
APSEC 2021, https://hal.archives-ouvertes.fr/hal-03419462
Abstract
Microservice architectures focus on developing modular and independent functional units, which can be automatically deployed, enabling agile DevOps. One major challenge is to manage the rapid evolutionary changes in microservices and perform continuous redeployment without interrupting the application execution. The existing solutions provide limited capacities to help software architects model, plan, and perform version management activities. The architects lack a representation of a microservice architecture with versions tracking. In this paper, we propose runtime models that distinguishes the type model from the instance model, and we build up an evolution graph of configuration snapshots of types and instances to allow the traceability of microservice versions and their deployment. We demonstrate our solution with an illustrative application that involves synchronous (RPC calls) and asynchronous (publish-subscribe) interaction within information systems.
