Abstract: Cloud computing has rapidly become a cornerstone of modern IT infrastructure, revolutionizing how organizations store, process, and manage data. By leveraging remote servers hosted on the internet, it enables scalable, on-demand access to computing resources, significantly reducing the need for physical infrastructure and associated costs. Its flexibility allows businesses to dynamically adjust resources based on demand, making it especially appealing for start-ups and enterprises alike. However, the transition to cloud environments is not without complications. This paper surveys the current literature on cloud computing, delving into its core architectures, such as multi-tenant systems and distributed computing frameworks. It examines various service models, including Infrastructure as a Service (IaaS), Platform as a Service (PaaS), and Software as a Service (SaaS), as well as deployment models like public, private, hybrid, and community clouds. The review identifies critical challenges that persist in the field, particularly in areas of data security, privacy, interoperability across platforms, and the risk of vendor lock-in, where organizations become overly dependent on a single provider. Furthermore, it explores ongoing research into mitigating these issues and investigates emerging trends such as edge computing, AI integration, and green cloud technologies, offering a comprehensive perspective on the evolving landscape of cloud computing

Keywords: Cloud Computing, Cloud Architecture, Service Models (IaaS, PaaS, SaaS), Security and Privacy, Resource Management, Multi-Cloud and Hybrid Cloud, Serverless Computing, Edge and Fog Computing, SLA (Service Level Agreement), Cloud Challenges and Research Issues.

| DOI: 10.17148/IARJSET.2025.12736