Cloud Computing Basics

###Cloud Computing

Cloud computing is the delivery of computing services over the internet. These services include common IT infrastructure such as virtual machines, storage, databases, and networking, enabling businesses to access and use IT resources without maintaining physical infrastructure.

###Cloud Models

The three main cloud models are: private, public, and hybrid.

1. >

   Private Cloud
   A private cloud is, in some ways, the natural evolution from a corporate datacenter. It’s a cloud that’s used exclusively by a single entity, providing more control and security over the computing resources.

2. >

   Public Cloud
   A public cloud is built, controlled, and maintained by a third-party cloud provider. Anyone who wants to purchase cloud services can access and use resources from the public cloud, which offers scalability and flexibility.

3. >

   Hybrid Cloud
   A hybrid cloud is a computing environment that uses both public and private clouds in an interconnected manner. It allows for greater flexibility and optimization by enabling private clouds to scale with public cloud resources when there's increased, temporary demand.

###Consumption-based Model

Cloud computing follows an OpEx (Operational Expenditure) model because it operates on a consumption-based approach. You don't pay for the physical infrastructure, electricity, security, or maintenance of a datacenter. Instead, you pay only for the IT resources you use. If no resources are used in a given month, you incur no charges for those resources.

###Benefits of Cloud

Cloud computing offers several key benefits:

1. >Availability: Ensures maximum availability, minimizing disruptions due to events or failures.
2. >Scalability: The ability to adjust resources in real-time based on demand, ensuring efficient resource allocation.
3. >Reliability: The ability of a system to recover from failures and continue to function smoothly.
4. >Predictability: Provides confidence in both performance and cost, allowing for predictable service and budget management.
5. >Governance & Compliance: Cloud platforms include features that support governance and compliance with corporate standards and government regulations. Templates help maintain these standards, and resources can be updated as standards change.

###Management in the Cloud

Managing cloud resources efficiently includes:

• >i. Automatic Scaling: Cloud services can automatically scale resources up or down based on demand.
• >ii. Template-based Deployment: Resources can be deployed based on pre-configured templates, eliminating manual configuration.
• >iii. Monitoring and Health Management: You can monitor the health of resources and automatically replace failing ones.
• >iv. Real-time Alerts: Automatic alerts based on predefined metrics help you track performance and issues in real time.

Cloud resources can be managed in several ways:

• >a. Web Portal: Through a web interface to configure and manage resources.
• >b. Command Line Interface (CLI): Allows for more granular control and automation.
• >c. APIs: For integration and management of resources programmatically.
• >d. PowerShell: Automation and scripting using PowerShell for managing cloud resources.

###Service Models in Cloud Computing

Infrastructure as a Service (IaaS)

In the IaaS model, the cloud provider is responsible for maintaining the physical hardware, network connectivity, and physical security of the cloud infrastructure. You, as the customer, are responsible for managing everything else, such as the operating system, network configuration, database, storage, and applications.

Platform as a Service (PaaS)

In a PaaS environment, the cloud provider manages the physical infrastructure, security, and internet connectivity, as well as the operating systems, middleware, development tools, and business intelligence services needed to build and deploy applications. The customer focuses on developing their own applications, without worrying about the underlying infrastructure.

Software as a Service (SaaS)

SaaS is the most complete cloud service model from a product perspective. With SaaS, you are essentially renting or using fully developed software applications hosted on the cloud. These applications are managed by the cloud provider and are accessible via the internet, freeing you from the need to install and maintain software on local systems.