Resilience of Stateful IoT Applications in a Dynamic Fog Environment

Abstract

Fog computing provides computing, storage and communication resources at the edge of the network, near the physical world. Subsequently, end devices nearing the physical world can have interesting properties such as short delays, responsiveness, optimized communications and privacy. However, these end devices have low stability and are prone to failures. There is consequently a need for failure management protocols for IoT applications in the Fog. The design of such solutions is complex due to the specificities of the environment, i.e., (i) dynamic infrastructure where entities join and leave without synchronization, (ii) high heterogeneity in terms of functions, communication models, network, processing and storage capabilities, and, (iii) cyber-physical interactions which introduce non-deterministic and physical world's space and time dependent events. This paper presents a fault tolerance approach taking into account these three characteristics of the Fog-IoT environment. Fault tolerance is achieved by saving the state of the application in an uncoordinated way. When a failure is detected, notifications are propagated to limit the impact of failures and dynamically reconfigure the application. Data stored during the state saving process are used for recovery, taking into account consistency with respect to the physical world. The approach was validated through practical experiments on a smart home platform.

Designing and Implementing Resilient IoT Applications in the Fog: A Smart Home Use Case

“…The resilience approach is designed taking into account the specificities of the environment. The practical experiments show the feasibility of the approach and that recovery is achieved in an acceptable delay from a user point of view [5]. Future work includes a performance evaluation on different testbeds and formal verification of the resilience protocol.…”

“…The resilience approach consists of four functional steps: (i) State Saving, (ii) Monitoring, (iii) Failure Notification and Reconfiguration, and, (iv) Recovery. [5] describes in details the resilience approach. In a first step, the states of applicative entities and the PW are saved in an uncoordinated way.…”

Design and Fabrication of Smart Home With Internet of Things Enabled Automation System

“…The framework was evaluated on a testbed inspired by [14], resulting in an actual SH application reproduction. Practical experiments showed the recovery and feasibility of the approach with acceptable delay from the user's point of view [31].…”

Learning Spatiotemporal Failure Dependencies for Resilient Edge Computing Services

“…Odin [52], is a practical application of fault tolerance for distributed servers in CDNs via backups. A checkpointing mechanism for stateful fog computing that saves message and function call records is proposed in [53]. This work focuses on failure recovery rather than avoidance.…”