###### Abstract  
Vehicular Edge Computing (VEC) provides users with low-latency and highly responsive services by deploying Edge Servers (ESs) close to applications. In practice, vehicles are usually moving rapidly. To ensure the continuity of services, edge service migration technology is in high need, by which an application, infrastructure or any edge-hosted applications or services are not locked into a single vendor and allowed to shift between different edge resource vendors. Nevertheless, due to their complex and dynamic nature, real edge computing environments are error and fault prone and thus the reliability of edge service migrations can be easily compromised if the proactive measures are not taken to counter failures at different levels. In this paper, we propose a novel fault-tolerant approach for Dynamic Redundant Path Selection service migration (DRPS). The DRPS approach consists of path selection algorithm and service migration algorithm. The path selection algorithm is capable of evaluating time-varying failure rates of ESs by leveraging a sliding window-based model and identifying a set of service migration paths. The service migration algorithm incorporates resubmission and replication mechanisms as well and decides edge service migration schemes by choosing multiple redundant migration paths. We also conduct extensive simulations and show that our proposed method outperforms traditional solutions by 17.45%, 13.17%, and 7.22% in terms of ACT, TCR, and AFC, respectively. vehicle edge computing; service migration; fault-tolerant; dynamic redundant path selection; time-varying failure rates +
Footnote †: journal: Applied Sciences  
In practice, edge service migration is in high need, by which an application, infrastructure or any edge-hosted applications or services are allowed to shift between different resource vendors or edge nodes when the original vendors or nodes are non-functional or overloaded [13; 14]. As the edge computing systems continue to grow in scale and complexity, it is of critical importance to ensure the stability, availability, and reliability in such systems. However, due to its intrinsic dynamic and decentralized nature, the edge computing infrastructure itself is fault and error prone [15]. The reliability of edge service migration can therefore be easily compromised if the proactive measures are not taken to tackle against the possible failures occurring at varying levels of the edge computing system. To guarantee reliable service migration, and as a countermeasure for faults and failures, the edge service providers have to enforce fault tolerance [16; 17; 18; 19]. Among various fault tolerance strategies in this direction, replication and resubmission are two widely used ones that are proved to be highly capable in mobile edge computing [20]. The replication-based fault-tolerance refers to the technique of running multiple redundant replicates for each and every service. Thus, if one part of the system goes wrong, it has other instances that can be placed instead of it to keep it running. Although running redundant replicas generally increases the operational overhead, it effectively prevents failures of components or individual resources from interrupting system-level task flows, thereby improving the efficiency of service execution. The resubmission-based fault-tolerance refers to re-executing a failed task on the same or another processing unit. Although re-executing a task costs extra time, it can improve the system resource utilization and effectively prevent the service interruption caused by task execution failure. Researchers have proposed many fault-tolerant schemes based on replication and resubmission [16; 21; 22; 23; 24; 25; 26]. This paper focuses on service migration in VEC environments and proposes a novel fault-tolerant approach for dynamic redundant path selection service migration in mobile edge computing, called DRPS, by synthesizing the replication and resubmission-based fault-tolerance techniques.