Smart Contracts for Service-Level Agreements in Edge-to-Cloud Computing

Abstract

The management of Service-Level Agreements (SLAs) in Edge-to-Cloud computing is a complex task due to the great heterogeneity of computing infrastructures and networks and their varying runtime conditions, which influences the resulting Quality of Service (QoS). SLA-management should be supported by formal assurances, ranking and verification of various microservice deployment options. This work introduces a novel Smart Contract (SC) based architecture that provides for SLA management among relevant entities and actors in a decentralised computing environment: Virtual Machines (VMs), Cloud service consumers and Cloud providers. Its key components are especially designed SC functions, a trustless Smart Oracle (Chainlink) and a probabilistic Markov Decision Process. The novel architecture is implemented on Ethereum ledger (testnet). The results show its feasibility for SLA management including low costs operation within dynamic and decentralised Edge-to-Cloud federations.

A Review of Blockchain-enabled Fog Computing in the Cloud Continuum Context

“…Some of the solutions (e.g. [14]) depend on external oracles which are trusted parties for monitoring the QoS. Alternately, the monitoring job can be delivered by the crowd.…”

“…Instead, a peer to peer network with a robust protocol can ensure the correctness of the monitoring process. [14,29,31] Result Verification Credibility-based fault tolerance protocols and zero-knowledge proofs can be used to determine if a node has executed the program as expected. These strategies are encoded in Smart Contracts which verify the proofs.…”

Who Is Contributing to Academic Research on Blockchain Oracles? A Bibliometric Analysis

“…Considering the most contributing authors, it emerges that the produced research is essentially done in cooperation with authors of the same department or with branches of the same University. Paper such as Kochovsky et al [66], for example, shows the contributions of multiple authors and institutions that, however, are not encountered in further studies. Therefore, it appears that there is no active and stable cooperation between institutions specialized in investigating blockchain oracles, nor among leading authors belonging to different institutions.…”

“…As for cloud computing, only three studies are retrieved. Two were published by the same institution and propose a trustless oracles system [66], [99], focusing on Service Level Agreement (SLA). On the other hand, the work proposed by Khalifa University approaches the problem of ensuring an optimal fees level to balance the needs of Cloud providers and users [100].…”

IoT Data Replication and Consistency Management in Fog Computing

“…It is predicted that, by 2025, there will be 75 billion connected objects producing 79.4 ZB of IoT data [4,6]. With this large growth, relying exclusively on traditional centralized Clouds for processing and storage purposes, would cause high access latencies and network congestion, degrading the Quality of Service (QoS) related to service latency of IoT applications [2,7]. On the other hand, IoT objects have become ubiquitous, which imposes the use of a geo-distributed architecture in order to overcome the high latency and the network congestion limitations of the centralized Cloud-based platform [9].…”