  Many future innovative computing services will use Fog Computing Systems
(FCS), integrated with Internet of Things (IoT) resources. These new services,
built on the convergence of several distinct technologies, need to fulfil
time-sensitive functions, provide variable levels of integration with their
environment, and incorporate data storage, computation, communications,
sensing, and control. There are, however, significant problems to be solved
before such systems can be considered fit for purpose. The high heterogeneity,
complexity, and dynamics of these resource-constrained systems bring new
challenges to their robust and reliable operation, which implies the need for
integral resilience management strategies. This paper surveys the state of the
art in the relevant fields, and discusses the research issues and future trends
that are emerging. We envisage future applications that have very stringent
requirements, notably high-precision latency and synchronization between a
large set of flows, where FCSs are key to supporting them. Thus, we hope to
provide new insights into the design and management of resilient FCSs that are
formed by IoT devices, edge computer servers and wireless sensor networks;
these systems can be modelled using Game Theory, and flexibly programmed with
the latest software and virtualization platforms.
