Achieving Observability on Fog Computing with the Use of Open-Source Tools

Fog computing can provide computational resources and low-latency communication at the network edge. But with it comes uncertainties that must be managed in order to guarantee Service Level Agreements. Service observability can help the environment better deal with uncertainties, delivering relevant and up-to-date information in a timely manner to support decision making. Observability is considered a superset of monitoring since it uses not only performance metrics, but also other instrumentation domains such as logs and traces. However, as Fog Computing is typically characterised by resource-constrained nodes and network uncertainties, increasing observability in fog can be risky due to the additional load injected into a restricted environment. There is no work in the literature that evaluated fog observability. In this paper, we first outline the challenges of achieving observability in a Fog environment, based on which we present a formal definition of fog observability. Subsequently, a real-world Fog Computing testbed running a smart city use case is deployed, and an empirical evaluation of fog observability using open-source tools is presented. The results show that under certain conditions, it is viable to provide observability in a Fog Computing environment using open-source tools, although it is necessary to control the overhead modifying their default configuration according to the application characteristics.