3 Models of Cloud Computing Services IaaS, PaaS, SaaS

I always hear 3 models of cloud computing services:

IaaS: Infrastructure-as-a-Service

PaaS: Platform-as-a-Service

SaaS: Software-as-a-Service
I. Cloud Computing
The National Institute of Standards and Technology (NIST) gave a definition of cloud computing in 2011:

Cloud computing is a model for enabling ubiquitous, convenient, on-demand network access to a shared pool of configurable computing resources (eg, networks, servers, storage, applications, and services) that can be rapidly provisioned and released with minimal management effort or service provider interaction.

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In other words, cloud computing is a model. Enables configurable computing resources (such as networks, servers, storage, applications, and services) to be available on-demand over the network, requiring minimal administrative work or simple interaction with service providers to quickly control the provision and freed

This cloud model consists of 5 basic features, 3 service models, and 4 deployment models:

This cloud model is composed of five essential characteristics, three service models, and four deployment models.

Among them, three service models are called * aaS

II. 5 basic characteristics
On-demand self-service: Users can unilaterally provision computing power, such as server time and network storage, as needed, without having to interact with each service provider manually
Broad network access: Features are provided over the network and accessed through standard mechanisms that can facilitate the use of various client platforms such as mobile phones, tablets, laptops, and workstations

Resource pooling: The supplier's computing resources are centrally used to provide services to multiple users through a multi-tenant model. Different physical and virtual resources are dynamically allocated according to user needs. There is a sense of location independence, because customers often have no control or the exact location of the resources provided, but can specify locations at a higher level of abstraction, such as a country, state, or data center. Resources include storage, processing, memory, and network bandwidth

Rapid elasticity: In some cases, functions can be automatically and flexibly configured and released to quickly expand outward and inward based on demand. For users, the features available for provisioning often look infinite and can be configured in any number at any time

Measured service: The cloud system automatically controls and optimizes resource use by leveraging metering capabilities on a layer of abstraction appropriate for the type of service (such as storage, processing, bandwidth, and active user accounts). Monitor, control, and report on resource usage, providing transparency to providers and consumers of the services used

III.3 service models

Infrastructure as a Service (IaaS): The functions provided to users are provisioning processing, storage, network, and other basic computing resources. Users can deploy and run any software, including operating systems and applications. program. Consumers do not manage or control the underlying cloud infrastructure, but they can control the operating system, storage, and deployed applications, and they have limited control over selected network components (such as host firewalls)

Platform as a Service (PaaS): The function provided to users is to implement them through programming languages, class libraries, services, and tools supported by vendors, or to deploy applications created to the cloud infrastructure on. Consumers do not manage or control the underlying cloud infrastructure including networks, servers, operating systems, or storage, but can control deployed applications and configuration options to configure the application hosting environment


Software as a Service (SaaS): The functionality provided to users is a vendor application that runs on a cloud infrastructure. Applications can be accessed through a thin client interface such as a web browser (such as Web email) or program interface to access from a variety of client devices. Users do not manage or control the underlying cloud infrastructure including networks, servers, operating systems, storage, or even individual application functions, but some user-specific applications Program configuration may require additional settings


The difference is mainly reflected in the degree of user control over resources:

Degree of control	IaaS	PaaS	SaaS
Control (needs maintenance)	Operating system applications handle other basic computing resources of the storage network	Deployment options for deployed applications	Some user-specific application configurations
Hosting (no need to care)	Network components	Network server operating system storage	Some application features web server operating system storage

From infrastructure to platform to software, the level of abstraction of resource supply forms is getting higher and higher, and the underlying facilities that users need to pay attention to are becoming less and less, as shown below:

IV. 4 deployment models

Private cloud: A cloud infrastructure is dedicated to a single organization consisting of multiple users (for example, business units). It may be owned, managed, and operated by an organization, a third party, or some combination of them, and may be on-premises or off-premises


Community cloud: Cloud infrastructure is dedicated to a specific consumer community of organizations with the same concerns, such as tasks, security requirements, policies, and compliance considerations. It can be owned, managed, and operated by one or more organizations, third parties, or some combination of them in the community, and may be on-premises or off-premises
Public cloud: Cloud infrastructure is open to the public. It can be owned, managed, and operated by a business, academia, government organization, or some combination of them. On-premises


Hybrid cloud: Cloud infrastructure consists of two or more different cloud infrastructures (private, community, or public) that are still unique entities, but are tied together through standardization or proprietary technology To enable portability of data and applications (such as cloud bursts to achieve cloud load balancing)


P.S. cloud bursting is a configuration built between private and public clouds to cope with peak IT demand. If an organization using a private cloud reaches 100% of its resource capacity, the overflowed traffic is directed to the public cloud without disrupting service