O que é qualquer coisa como serviço (XaaS)?

SaaS, IaaS, and PaaS are the three most important delivery models. Building on these three many other service models have become available to the market. Popular Anything as a Service models include:

• IaaS — Infrastructure as a Service is a cloud model where businesses outsource their IT infrastructure to a managing provider. The most basic form of IaaS is bare-metal service which allows a single tenant access to a server housed at a cloud provider. This form often does not utilize a hypervisor or containers for virtualization, and essentially emulates on-premise infrastructure. Today, however, most IaaS providers use virtualization to achieve greater efficiencies with their underlying server infrastructures. Beneficial for businesses, IaaS allows them to offload the management, updates, networking, and security to the cloud provider.
• PaaS — Platform as a Service is a step beyond IaaS in that it provides an environment for cloud consumers to access via the web. Like IaaS, PaaS delegates the lower functions, like servers, operating systems, and storage to the cloud provider, allowing the consumer to focus on their necessary work. PaaS is made functional through application programming interfaces (API), and a variety of dev tools and databases whereby developers can develop and deploy applications, even control the application hosting environment.
• SaaS — Software as a Service is a cloud model that provides on-demand software applications typically via a web browser and internet. SaaS is a modernized terminology for application service provider (ASP) software which has existed before “the cloud” came into common usage. SaaS is highly beneficial for businesses who have limited budgets to manage their own IT systems. SaaS provides a quick service model for key applications such as customer relationship management (CRM), enterprise resource planning (ERP), human resources (HR), and payroll applications.
• CaaS — Communication as a Service offers businesses enterprise level communication services. Services can include voice over IP (VoIP), virtual private network (VPNs), private branch exchange (PBX) without the infrastructure costs. CaaS benefits business the same as other XaaS, with the service provider assuming the management responsibilities of the underlying software and infrastructure.
• DBaaS — Database as a Service is a specialized software delivery model for database operations. CSPs offer self-service database provisioning, monitoring of quality of service levels, and measurement of database usage for charging back individual cloud customers.
• BPaaS — Business Process as a Service combines business process management (BPM) with other XaaS service models (SaaS, IaaS, PaaS). BPaaS makes company workflows more efficient, and the agility of these systems to adapt to changing business requirements helps future-proof these workflows.

There are potential disadvantages of using an XaaS service, and stemming from the reliance on an outside provider for the X service.

The most critical drawback is downtime. If the provider’s service goes down, making the service unreachable, all business operations that rely on that service will be disrupted. This can be mitigated by relying on a competent, reliable, industry-leading provider, or in some configurations multiple providers. To a lesser degree, performance is a second drawback. While not as potentially devastating as a critical system outage, poorly performing services can still cause disruptions, and loss of revenues.

The last disadvantage varies depending on the XaaS model service type. By employing a service model, companies effectively outsource those IT functions, and likewise part of that responsibility. Illustrated in the Accountability and Share Responsibility Model is a framework for how providers and consumers should share partnership of the data and services within their respective domains.

As the cloud service model moves from a general Infrastructure as a Service (IaaS) model to a specific Software as a Service (SaaS) model, the share of responsibility falls more heavily on the cloud service provider. Imagine renting server racks, the provider’s responsibility amounts to keeping the servers running and their connectivity strong. Beyond that, covering application-level controls and above is the responsibility of the cloud user. Whereas, providers of financial SaaS will be required to have strong identification and access controls. Data security and protection is subject to regulations, and the shared burden of the cloud provider and consumer.