  The microservices architectural approach has important benefits regarding the
agile applications' development and the delivery of complex solutions. However,
to convey the information and share the data amongst services in a verifiable
and stateless way, there is a need to enable appropriate access control methods
and authorisations. In this paper, we study the use of policy-driven
authorisations with independent fine-grained microservices in the case of a
real-world machine-to-machine (M2M) scenario using a hybrid cloud-based
infrastructure and Internet of Things (IoT) services. We also model the
authentication flows which facilitate the message exchanges between the
involved entities, and we propose a containerised authorisation and
policy-driven architecture (CAPODAZ) using the microservices paradigm. The
proposed architecture implements a policy-based management framework and
integrates in an on-going work regarding a Cloud-IoT intelligent transportation
service. For the in-depth quantitative evaluation, we treat multiple
distributions of users' populations and assess the proposed architecture
against other similar microservices. The numerical results based on the
experimental data show that there exists significant performance preponderance
in terms of latency, throughput and successful requests.
