3.1: Introduction and Definition of Cloud Computing

Structure of Cloud Platforms:

At a high level, a cloud platform’s structure can be viewed in layered terms:

• Physical Layer (Data Centers): Cloud providers operate vast data centers around the globe, housing racks of servers, storage systems, and network equipment. These facilities are organized into regions (geographically distinct locations) and further into availability zones (isolated data center clusters within a region) for redundancy and low latency. For example, AWS spans 34 regions with 108 availability zones worldwide, while Google Cloud (GCP) spans 40 regions with 121 zones. This geographic distribution enables high availability and allows customers to choose where to deploy resources to be close to users or meet data sovereignty requirements.
• Virtualization and Abstraction Layer: On top of the hardware, cloud platforms employ virtualization software and orchestration systems. A hypervisor or container runtime abstracts the physical servers into virtual machines (VMs) or containers that can be easily created, moved, or deleted. This layer is what allows the cloud’s elastic resource pooling – workloads run in virtualized environments decoupled from the underlying physical host. Providers also add an orchestration/ management layer that automates deployment of these VMs/containers, balances load, and monitors health.
• Cloud Services and APIs: Above the core infrastructure, clouds offer a catalog of services accessible via APIs or web consoles. These range from basic compute and storage (e.g. virtual servers, object storage buckets) to higher-level services (databases, big data analytics, machine learning APIs, etc.). The cloud’s control plane includes components like authentication, resource management, billing, and monitoring – the plumbing that delivers the on-demand self-service experience.
• User Access Layer: Finally, users interact with the cloud via web portals, command-line interfaces, or SDKs. This is how they request resources (e.g. launching a VM, deploying an application) and manage their cloud environment. Cloud platforms provide dashboards for visibility into usage, performance, and costs.

In summary, a cloud platform is a sophisticated integration of distributed data centers, virtualization technology, and automated management software that together provide flexible, utility-like IT resources to consumers. The following sections will delve deeper into the formal service models of cloud computing, specific leading cloud providers, and the fundamental technologies that make cloud platforms possible.