BUSCADOR RECOLECTA

As society's dependence on Information and Communication Technologies (ICTs) grows, providing efficient and resourceful services entails many complexities that require, among others, scalable systems that are provided with intelligent and automated management. In parallel, the different components of cloud computing are continuously evolving to enhance their capabilities towards leveraging the next generation of ICTs. Due to the substantial investment in resources required to provide efficient services, suitable research and experimentation platforms to test and validate cloud technologies before releasing them into operational versions are crucial to delivering sound systems with sustainable cost/benefit ratios. In this article, we review the current state of the art by analysing cloud testbeds devoted to studying the capabilities of the cloud continuum. Instead of recalling a component-wise or architectural discussion of these systems, this article explores the full spectrum of the cloud continuum testbeds and their features, providing a taxonomy that can be practically used as an entry point to identify each testbed's scope. Moreover, we extract the challenges found in the literature to deliver a profound discussion, correlating the analysed testbeds and their features. Our findings highlight the main gaps and potential roadmaps to provide effective testbeds considering the next generation of ICTs., This work was supported by the European Commission under the Horizon Europe Programme, as part of the projects SAFEHORIZON
(Grant Agreement no. 101168562), LAZARUS (Grant Agreement no. 101070303) and HEROES (Grant Agreement no. 101021801). This work was also supported by the European Union's Internal Security Fund as part of the ALUNA project (Grant Agreement no. 101084929). This work was also supported by the COST Action GoodBrother, Network on Privacy-Aware Audio-and Video-Based Applications for Active and Assisted Living, (CA 19121). This work was partially supported
by Ministerio de Ciencia, Innovación y Universidades, Gobierno de España (Agencia Estatal de Investigación, Fondo Europeo de Desarrollo Regional -FEDER-, European Union) under the research grant PID2021-127409OB-C33 CONDOR. Fran Casino was supported by the Spanish Ministry of Science and Innovation under the 'Ramón y Cajal' programme (RYC2023-044857-I), and by AGAUR with the project ASCLEPIUS (2021SGR-00111).