A Bird's Eye View of Today's Cloud Computing Service Delivery Models

The cloud enables on-demand services, platforms and applications that allow businesses to scale up pretty much any function or workload.

By Dipti Parmar

By Dipti Parmar September 22, 2021

The cloud is clearly the present and the future of computing and technology infrastructure. Organizations of all sizes, in pretty much every vertical, have already adopted and deployed cloud-based apps and services as part of their current IT functions.

Cloud has evolved to encompass public (or off-premises) cloud services and private (or on-premises) cloud technology-powered data centers. For the past few years, IT pros say hybrid multicloud is the “ideal IT operating model” for their organizations, as reported by the Nutanix Enterprise Cloud Index (ECI).

Public cloud adoption continues to grow while cloudification of owned data centers is becoming the norm with virtualization and hyperconverged infrastructure (HCI) technologies – 92% of ECI respondents who currently run on-premises infrastructure have deployed or plan to deploy HCI. With the technology and cloud markets having matured significantly, IT leaders have clearly indicated that business outcomes take precedence over cutting costs. The hybrid cloud infrastructure remains a draw because it offers a great many business benefits over competing IT deployment models.

Among those who use public clouds, more than 70% of ECI respondents were expected to use two or more public clouds by the end of 2020. This indicates that businesses are looking for the flexibility delivered by different public cloud providers.

“The pandemic validated cloud’s value proposition,” said Sid Nag, VP Analyst at Gartner. “The ability to use on-demand, scalable cloud models to achieve cost efficiency and business continuity is providing the impetus for organizations to rapidly accelerate their digital business transformation plans. The increased use of public cloud services has reinforced cloud adoption to be the ‘new normal,’ now more than ever.”

While the business benefits are clear, how do organizations choose which functions or workloads should run in private or public clouds? For this, they need to understand the different types of cloud services, how they satisfy a specific set of business needs and how they can be moved between private and public cloud if and when it makes sense.

What are cloud services and how are they delivered?

Cloud services give the organization different levels of IT infrastructure capabilities encapsulated under a software framework. They are “delivered” by vendors or providers to consumers or end users by way of three major models:

Software as a Service (SaaS): The vendor builds and manages applications for various business functions and delivers them to users via the internet. These apps are hosted on the provider’s infrastructure. On the client side, they run on web browsers and don’t require any downloads or installations.

Platform as a Service (PaaS): Developers on the client side can create customized applications, and deploy and manage them on the provider’s infrastructure. The provider manages the underlying OS, middleware, and hardware virtualization.

Infrastructure as a Service (IaaS): The consumer has the freedom to architect, deploy, and manage the application on the virtual resources provided by the vendor. They can buy and automate VMs and virtualized hardware resources on-demand instead of having to purchase hardware while the provider manages the actual servers, storage, and networking.

Compared to on-premises datacenters where IT needs to purchase, manage, and upgrade all software and hardware resources, cloud services help reduce the twin burdens of skilling up and CAPEX for technology.

Apart from these, there are secondary -as-a-Service cloud offerings that give more control over particular workloads to customers. These services are highly customized and function-specific. More on this later.

A distinction of note: cloud service models are different from cloud deployment models. The deployment model – such as public, private, or hybrid cloud – defines the underlying architecture over which cloud services are implemented or delivered.

Now for a closer look at the primary cloud service models…

Software as a Service (SaaS)

SaaS offers the whole package from applications to OS to infrastructure that users can seamlessly access with the simplest of devices and minimal bandwidth. The amount of software services available is vast and caters to every imaginable business function, such as invoicing, project management, file sharing, communications, and so on.

Examples: Dropbox, Slack, Basecamp


  • Lightweight: SaaS is the ideal choice for small businesses that can do with off-the-shelf software and don’t have the in-house IT skills or resources to deploy on-premises hardware.
  • Affordable: There are no upfront infrastructure setup costs. Software licensing costs are also charged on a pay-per-use subscription model.
  • Highly accessible: SaaS services can be set up and configured in no time. Further, they can be accessed using virtually any device – from a smartphone to a bulky desktop – from any place with an internet connection.

Limitations and Concerns:

  • Vendor lock-in: SaaS providers make it easy to get into but not so easy to get out of their ecosystem. This limits integration and interoperability with other apps and services. Data portability is limited by the file formats or standard APIs that the vendor provides.
  • Limited features: One-size-fits-all is the basic premise of SaaS apps, so there is very limited scope for customization. Customers are limited to out-of-the-box features.
  • Lack of control: Data security and governance lies in the hands of the provider. Customers have little control over the software in terms of appearance, updates, or data storage and transfer methods. This might lead to compromised security, inadequate performance, or downtime.

Platform as a Service (PaaS)

PaaS provides special software components, APIs, scripts, and tools that allow consumers to build scalable and highly available applications that conform to popular architectures. This lets developers quickly build, test, and deploy apps iteratively without the need for extensive internal infrastructure resources. These apps might not be fully customizable but the shortening of the development cycle and simplicity of management more than compensate for that.

Examples: Heroku, Cloud Foundry, AWS Elastic Beanstalk


  • Fast development: With on-demand availability of server-side components and compute resources, developers can speed up testing and production processes.
  • Multiple language support: Inherent support for all major programming languages gives developers the flexibility to build software that delivers the highest performance for any given workload or project.
  • Collaboration: Development teams spread over different geographic locations can develop and host applications in the same environment without the need for transferring or syncing data, or files. Everyone has access to up-to-date information and code versions in real-time.

Limitations and Concerns:

  • Data security: Even though companies run their own apps and services, ultimately the data resides in the vendors’ servers, raising security and compliance concerns.
  • Complexity in integration: The provider may not necessarily have the integration modules to connect legacy apps and services to the cloud. This might warrant extra customization on the client side.

Infrastructure as a Service (IaaS)

IaaS gives enterprises the ability to build and use a “datacenter in the cloud” without buying expensive hardware outright. When a company needs to rapidly deploy IT infrastructure but doesn’t have the ability to do so in-house, IaaS provides on-demand access to server, storage, or networking resources via the internet. IaaS also offers the choice of a public, private, or hybrid cloud environment.

Examples: Digital Ocean, Linode, Rackspace, Microsoft Azure


  • Flexibility: Organizations can scale up (or down) the infrastructure and VMs on demand, according to project-specific requirements.
  • Reliability: The underlying hardware is housed across remote datacenters, eliminating the threat of a single point of failure. Further, the infrastructure is virtualized, provisioned, and managed by skilled IT personnel at major providers, minimizing the possibility of downtime.

Limitations and Concerns:

  • Training for staff: The organization needs resources and training for IT admins to be able to effectively monitor and manage the infrastructure.
  • Security: IaaS uses a multi-tenancy architecture for storage and server resources. The onus is on the vendor to prevent unauthorized access to customer data on storage assets or VMs.

Everything as a Service (XaaS)

XaaS is an umbrella term that encompasses any service that delivers a specific function or operational facility over the cloud. Here are a few examples:

Data as a Service (DaaS): The provider delivers cloud-hosted virtual desktops over the internet, licensed on a per-user basis.

Database as a Service (DBaaS): These services enable the setup, configuration, operation, and scaling of databases without the need for physical servers or storage on the client side.

Desktop as a Service (DaaS): A range of data services, such as analytics, storage, data warehousing, data processing, and data virtualization that are provided on-demand via the cloud, along with software tools for managing and working with data.

Unified Communication as a Service (UCaaS): UCaaS is a cloud delivery mechanism for enterprise communications. It integrates phone, email, instant messaging, and video conferencing into an integrated system.

Business Process as a Service (BPaaS): Strategically combining elements of SaaS and PaaS, BPaaS packages process design, implementation, and optimization capabilities into a software that can be customized by clients with their own logic.

Security as a Service (SECaaS): The provider packages data and information security services – including intrusion detection, penetration testing, and antivirus – into a subscription that reduces the TCO of security for client organizations.

Precipitating Service Delivery

Each cloud service delivery model has its own set of pros and cons. Organizations need to carefully evaluate which model and architectures will work best for their business needs, objectives, and projects.

Meanwhile, cloud technology keeps influencing change and disruption across all business segments, even more so during these uncertain times. It’s safe to claim that innovation and experimentation driven by cloud services will continue to bolster organizational capabilities.

In such a scenario, Gartner expects worldwide spending on public cloud services to top $480 billion by the end of 2022.

“The economic, organizational and societal impact of the pandemic will continue to serve as a catalyst for digital innovation and adoption of cloud services,” said Henrique Cecci, Sr. Research Director at Gartner.

“Cloud will serve as the glue between many other technologies that CIOs want to use more of, allowing them to leapfrog into the next century as they address more complex and emerging use cases,” added Nag.

Featured image by Pxfuel

Dipti Parmar is a marketing consultant and contributing writer to Nutanix. She writes columns on major tech and business publications such as IDG’s CIO.com, Adobe’s CMO.com, Entrepreneur Mag, and Inc. Follow her on Twitter @dipTparmar and connect with her on LinkedIn.

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