A Systematic Review of Federated Scheduling in the Cloud-Edge-IoT Continuum

abstract

The orchestration of applications across the IoT–Edge–Cloud (CEI) continuum is a fundamental enabler of today’s internet services and global digitization, supporting adaptive resource management and performance optimization in heterogeneous environments. Within this orchestration process, scheduling and placement constitute critical decision mechanisms that determine how computational tasks and services are allocated across federated infrastructures. This paper presents a survey of scheduling approaches designed to support application orchestration across the continuum. Through a systematic analysis of 63 peer-reviewed studies published between 2019 and 2025, the survey consolidates a fragmented body of knowledge encompassing diverse objectives, architectural paradigms, and evaluation practices. A comprehensive taxonomy is proposed to structure existing work along key analytical dimensions, including scheduling objectives, problem scale, architectural models, and evaluation methodologies. The analysis highlights the research gaps and emerging challenges, contributes to an integrated perspective on the status of federated orchestration and scheduling strategies. This study reveals that scheduling research in CEI continuum remains focused on single-cluster and small-scale evaluations, as more than 70% of the reviewed articles focused on single-cluster environments and about 79% of the studies evaluated their methods in small-scale environments. The exploration of fully decentralized multi-cluster architectures, and using large scale evaluation are still limited.