Cloud Systems and Technologies

- Overview

Cloud computing is the practice of using a network of remote servers hosted on the Internet to store, manage, and process data, rather than a local server or a personal computer. 

As cloud computing becomes mainstream, organizations are now moving toward adopting it into the in-house processes. As such, almost all industries are witnessing an increase in the use of cloud-based platforms and services. 

- Cloud Computing Environments

A cloud computing environment refers to the infrastructure and services delivered over the internet, allowing users to access computing resources like storage, servers, databases, and applications on demand, without the need for physical hardware management. It's a paradigm shift from traditional on-premise computing, offering flexibility, scalability, and cost-efficiency. 

1. Cloud Computing: The delivery of computing services - including servers, storage, databases, networking, software, analytics, and intelligence - over the Internet.

2. Cloud Services: Cloud computing is often categorized by the types of services offered, including:

- Cloud Servers

A cloud server is a pooled, centralized server resource that is hosted and delivered over a network (usually the Internet) and accessed on-demand by multiple users. 

Cloud servers can perform all the same functions as traditional physical servers, providing processing power, storage, and applications. Cloud servers can be located anywhere in the world and provide services remotely through a cloud computing environment. 

A cloud server is a virtual server hosted remotely that provides computing power, storage, and applications accessible over the internet, allowing multiple users to access it on-demand, unlike a traditional physical server which is dedicated to a single organization and located on-premises.

• Scalability: Cloud servers can be easily scaled up or down to meet changing resource needs, unlike physical servers which require significant upfront investment and time to adjust.
• Flexibility: Cloud servers can be accessed from anywhere with an internet connection, allowing for remote access and flexible working.
• Pay-as-you-go model: Cloud servers often follow a pay-as-you-go model, meaning users only pay for the resources they use, making them cost-effective for variable workloads.
• Reliability: Cloud providers typically maintain and manage the infrastructure, ensuring high uptime and reliability.
• Shared resources: Cloud servers are often shared by multiple users, which allows cloud providers to offer lower costs compared to dedicated servers.

- The Core of Cloud Computing - The Internet

Cloud computing's core is the Internet, which acts as the delivery mechanism for services like storage, processing power, and software. Essentially, cloud computing involves accessing these services over the internet from remote servers (the "cloud") rather than relying solely on local hardware. This allows for flexibility, scalability, and cost-effectiveness, as users can access and pay for only the resources they need. 

• Internet as the Backbone: The internet provides the fundamental infrastructure for cloud computing, allowing users to connect to remote servers and access cloud services.
• Remote Servers: Cloud services are hosted on servers located in data centers, often managed by cloud providers like Amazon Web Services (AWS), Microsoft Azure, or Google Cloud.
• On-Demand Access: Users can access these services on demand, meaning they can provision resources as needed and only pay for what they use, according to GDC IT Solutions.
• Flexibility and Scalability: Cloud computing offers flexibility to scale resources up or down based on demand, and users can access services from anywhere with an internet connection.
• Core Components: The "cloud core" includes various components like compute, storage, functions, containers, and database services.
• Virtualization: Virtualization technologies, like hypervisors, allow multiple virtual machines to run on a single physical server, maximizing resource utilization.
• Cost-Effectiveness: By using cloud services, businesses can reduce their capital expenditure on hardware and infrastructure, leading to cost savings.

- Classifications of Cloud Computing

Cloud computing can be classified based on location and the services it offers. Location-based classifications include Public, Private, Hybrid, and Community clouds. Service-based classifications include Infrastructure as a Service (IaaS), Platform as a Service (PaaS), and Software as a Service (SaaS), along with other service types like Storage, Database, Information, Process, Application, Integration, Security, Management, and Testing as a service.

Cloud Deployment Models (Location-based): 

• Public Cloud: Services are delivered over the internet by a third-party provider, accessible to the general public.
• Private Cloud: Resources are dedicated to a single organization, either on-premises or managed by a third party.
• Hybrid Cloud: Combines public and private clouds, allowing data and applications to be shared between them.
• Community Cloud: Shared infrastructure and resources for a specific community with shared concerns (e.g., regulatory compliance).

Cloud Service Models (Service-based): 

• IaaS (Infrastructure as a Service): Provides fundamental computing resources like servers, storage, and networking. Users manage the operating systems and applications.
• PaaS (Platform as a Service): Offers a platform for developing, running, and managing applications, including the infrastructure and tools.
• SaaS (Software as a Service): Delivers fully functional software applications over the internet, managed by the provider.
• Other service types: Include storage, database, information, process, application, integration, security, management, and testing services, often built on top of the core IaaS, PaaS, and SaaS models.

[Cloud Computing Layers - ResearchGate]

- Five Key Characteristics of A Cloud Computing

There are five key characteristics of a cloud computing environment, as defined by the National Institute of Standards and Technology (NIST): internet access, measured services, on-demand self-service, shared resource pooling, and rapid elasticity. 

• Internet Access: With a public cloud environment, users "plug into" the data and applications via an internet connection giving anytime, anywhere access. 
• Measured Service: Cloud is often pay-as-you-go, where you only pay for what you use. Think about how a utility company meters how much water, electricity, or gas is used and charges based on consumption. The cloud is the same. 
• On-Demand Self-Service: Services can be requested and provisioned quickly, without the need for manual setup and configuration. 
• Shared Resource Pooling: Cloud often uses the multi-tenancy model. This means a single application is shared among several users. So, rather than creating a copy of the application for each user, several users, or "tenants" can configure the application to their specific needs. 
• Rapid Elasticity: Cloud platforms are elastic. An organization can scale its resource usage levels up or down quickly and easily as needs change.

- The Core of Cloud Computing Technologies

There are two key elements at the core of cloud computing technology, which are: SOA (Service Oriented Architecture) and cloud virtualization, which are described in further detail below:

• SOA or Service Oriented Architecture defines a way to make software components reusable and interoperable through service interfaces. Services use common interface standards and architectural patterns so they can be quickly integrated into new applications. This removes the task of previously reinventing or duplicating existing functionality or application developers who must know how to connect to existing functionality or provide interoperability with existing functionality.
• Virtualization is the basic technology that supports cloud computing. Virtualization is software that manipulates hardware, while cloud computing refers to the services that result from this manipulation. It is impossible to have cloud computing without virtualization. Cloud computing is based on a virtualization technology where software called a hypervisor runs on a real machine and creates a virtual operating system on that specific machine. These virtual machines can run any application on them. Therefore, end users can easily use cloud services.