Fuzzy ACID properties for self-adaptive composite cloud services execution

摘要

The ACID transaction model has played a cornerstone role in service composition to guaranteethat composite services (CSs) have transactional support and consistent outcomes even inpresence of failures. However, the classical ACID properties are too restrictive for independentand multi-proprietors services running on distributed environments, such clouds. Transactionalproperties allow a relaxed atomicity and isolation, providing an “all-or-(almost)nothing” model.In previous works, we proposed a model to relax atomicity, called fuzzy atomicity, according userrequirements (acceptable fuzzy atomicity). In this article, we extend that model and propose anapproach to measure the fuzzy atomicity.Our model allows to self-adapt the CS execution, takinginto account the state of the CS execution and user preferences (ie, the acceptable fuzzy atomicityexpressed in the user requirements). This fuzzy atomicity measure is applied in a self-adaptive CSexecutionmodel based on the transactional properties (pivot, compensatable, and retriable) of itscomponent services and on a checkpointing mechanism. It is suitable to cloud computing, whichoffers cloud services on demand and in which CS execution should preserve the self-organizingand self-adaptivity properties of such environment, specially in the presence of failures.We showhow it is possible to relax the retriable property in CSs execution, based on our fuzzy atomicitymodel. Additionally, in this work, we present a comparative analysis of the most recent works inthe context of ACID properties relaxation for CS.