NebulOuS will transparently manage all the layers of the cloud continuum stack, in an equivalent manner to an OS managing the available computing capacity to facilitate an adaptive application hosting environment, driven by the processing proximity to data sources and optimised based on the data involved, the defined QoS requirements and the regulatory, security or privacy constraints. NebulOuS will introduce an appropriate meta-operating system that encompasses brokerage capabilities across the cloud computing continuum. Specifically, it will enable the emergence of ad-hoc fog brokerage ecosystems that exploit IoT/edge and fog nodes, in parallel to multi-cloud resources to cope with the requirements of hyper distributed applications. Such applications will be managed by NebulOuS considering the full life-cycle support of edge and cloud resources to enable hosting nodes across organisational units of the same or different business entities or reach private datacentres of telecom providers, constituting ad-hoc cloud computing continuums.

Semantic modelling for Cloud and Fog Computing
NebulOuS will offer the Fog Situational Awareness (FSA) model, for capturing all those knowledge artefacts that are required for establishing situational awareness.
SLAs in Cloud Computing Continuum
NebulOuS will offer a mechanism that will automatically generate SLA templates based on the FSA and ARP models: one for describing QoS capabilities at the resource provider(s), and one for describing the requesters’ QoS requirements and preferences.
Quality assurance in Fog Brokerage Service
NebulOuS will go a step further towards ensuring the quality of its brokerage services by offering the Organisational Requirements Definition Governance and Enforcement (ORDGE) mechanism for assessing the quality of the SLA templates generated from the ARP model
Service Discovery Policies & Fog Services Intermediation
NebulOuS will reinforce its brokerage capability by providing a preference-based fog service recommender for ranking fog services in cloud continuums. The recommender will operate based on a set of service discovery policies that are in turn formulated based on the quantitative, qualitative, and imprecise metrics populated in the ARP model.
Optimization in Cloud and Fog application deployment
NebulOuS will reinforce its brokerage capability by optimising application execution in the cloud continuum.
Deployment & Workflow Orchestration in Cloud Computing Continuum
NebulOuS will offer a mechanism that will leverage existing work on application deployment and orchestration over federated clouds and extend it to cloud continuums. Also, NebulOuS will offer support for serverless deployments in the cloud continuum.
IoT Interoperability
NebulOuS will offer a communications middleware that adopts standardised messaging protocols, e.g., MQTT/AMQP publish/subscribe (pub/sub), for realising data flows between applications and IoT devices (sensors, actuators).
Self-adaptive and proactive reconfiguration
NebulOuS will introduce intelligent and efficient reconfiguration support, a critical feature for maintaining applications deployed on cross-cloud and fog computing resources.
Security & Privacy by design
NebulOuS will offer seamless and secure connectivity among application components deployed in the cloud continuum. To this end, it will provide a mechanism that adopts Network Function Virtualization (NFV) practices to create a dynamic and scalable network overlay over these components.
Blockchain-enabled SLA
NebulOuS will offer an efficient, lightweight, fault-tolerant monitoring mechanism for providing feedback regarding the QoS aspects of application execution. This feedback is required for automatically reconfiguring application placement, as well as for determining SLA violations.
AI-driven anomaly detection
NebulOuS will reinforce its brokerage capability by detecting anomalies in application executions. To this end, NebulOuS will offer a mechanism that employs detection processes powered by AI-driven algorithms that continuously seek to detect, or predict, deviations in the QoS characteristics of application executions with respect to their contracted SLAs

Funded by the European Union. Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or Directorate-General for Communications Networks, Content and Technology. Neither the European Union nor the granting authority can be held responsible for them.