Cloud Computing Architecture Unit II

Cloud Computing Architecture

• Utility-oriented data centers underpin cloud computing, providing the infrastructure for service implementation and delivery.
• Cloud services, including hardware, platforms, and software, utilize distributed infrastructure, either provider-owned or rented from third parties.
• Implementation of cloud computing can occur through various setups, such as data centers, cluster collections, or heterogeneous distributed systems combining desktop PCs, workstations, and servers.
• Clouds are generally constructed using one or more data centers, often leveraging virtualized hardware resources for workload isolation and efficiency.
• Different service layers can be applied over virtual infrastructure, including virtual machine managers, development platforms, or specific middleware applications.
• Cloud computing delivers IT services on-demand in an Internet-centric manner, encompassing the entire computing stack.

Cloud Computing Reference Model

• Cloud computing facilitates IT services consumed as utilities over the Internet, covering infrastructure, development platforms, and applications.

Architecture

• Organized into a layered structure, the architecture spans from hardware appliances to comprehensive software systems.
• Physical infrastructure can be heterogeneous, consisting of various resources, like clusters and networked PCs, managed by core middleware.
• Core middleware provides a runtime environment for applications, optimizing resource usage while ensuring application isolation through virtualization technologies.
• Hypervisors manage hardware resource pools, converting them into collections of virtual machines, which allows fine partitioning of CPU and memory.
• Programming-level virtualization can create portable runtime environments tailored to specific technologies or languages (e.g., Java, .NET, Python).

Infrastructure as a Service (IaaS)

• IaaS solutions are crucial for cloud management and typically categorized into companies offering management layers and those providing both management and infrastructure.
• IaaS is efficient for designing system infrastructure yet provides limited application-building capabilities.
• Infrastructure- and Hardware-as-a-Service (IaaS/HaaS) deliver customizable infrastructure on-demand using hardware virtualization.
• Web services and RESTful APIs enable automated program interaction with service components, promoting integration within software systems.
• Centralized management layers (like schedulers) coordinate virtual machine instances and manage tasks such as pricing, billing, and monitoring.

Software as a Service (SaaS)

• SaaS applications are deployed from centralized data centers across networks, available on a subscription or recurring fee basis.
• Users achieve access to the applications without owning them, with varied business models impacting pricing and efficiency.
• Initially, Application Service Providers (ASPs) offered hosted solutions for packaged applications, sharing core characteristics with SaaS, such as application access and centralized management.
• As cloud computing evolved, SaaS became integrated with broader cloud computing services, emphasizing a one-to-many software delivery model.