As a service
This article relies too much on references to primary sources. (February 2021) (Learn how and when to remove this template message)
This article needs additional citations for verification. (July 2016) (Learn how and when to remove this template message)
*aaS is an acronym for as a service (e.g., X as a service), and refers to something being presented to a customer, either internal or external, as a service, always in the context of cloud computing.[original research?]. As a Service, or XaaS (Anything as a Service) offerings provide endpoints for customers/consumers to interface with which are usually API driven, but can commonly be controlled via a web console in a user's web browser.
Internally these often complex systems generally possess a high degree of internal automation which generally provide varying levels of fault tolerance and resiliency, the ability to scale up/down in or out to meet capacity and performance requirements of the workloads submitted to the service by its users/consumers, and are usually intended to operate their day to day functions without the need for human intervention. IaaS features most commonly included in this automation package are compute, storage, network, telemetry, and logging/accountability features, but most IaaS components owe some portion of their workload to these services. The current cloud computing ecosystem contains multiple cloud providers, each with their own menu of these services for their customers to consume on-demand or in some cases even with pre-scoped capacity agreements. 
Because (X)aaS services are generally based on open source projects with little to no licensing costs, ideally require little to no human intervention to perform their tasks/roles, could possibly be scaled out on demand to the full physical resource capacity of an entire datacenter region, are maintained and supported internally by the cloud provider, and use resources that are expendable for reuse by other IaaS tasks and services, XaaS services represent a large cost savings over traditional vendor-provided infrastructure and server based equivalencies, which often include vendor-specific lock-in features and imposed product feature set limitations which focus more around supporting that vendor's product portfolio and feature roadmap than similar open source projects.
|Look up -aaS in Wiktionary, the free dictionary.|
- Robin Hastings, Making the Most of the Cloud: How to Choose and Implement the Best Services (2013), p. 3.
- "Open Source Cloud Computing Platform Software". OpenStack.
- "What is edge computing? | Cloudflare".
- "Contact Center as a Service Reviews | Gartner Peer Insights". Gartner. Retrieved 2020-09-22.
- "Energy as a Service (EaaS)". www.se.com.
- I. A. Umoren, and M. Z. Shakir, EVaaS: a novel on-demand outage mitigation framework for electric vehicle enabled microgrids. in Proc. IEEE Globecom WS, Abu Dhabi, 2018, p. 6.
- I. A. Umoren, S. S. A. Jaffary, M. Z. Shakir, K. Katzis and H. Ahmadi, "Blockchain-Based Energy Trading in Electric Vehicle Enabled Microgrids," in IEEE Consumer Electronics Magazine, doi: 10.1109/MCE.2020.2988904.
- "Firewall (FWaaS) Delivered as a Service | Firewall-as-a-Service".
- McLean, Richard (Jan 9, 2020). "Governance as a service". Medium.
- "OpenStack Docs: Octavia Documentation". docs.openstack.org.
- "MAAS | Metal as a Service". maas.io.
- Musthaler, Linda (Apr 5, 2018). "Network-as-a-Service: Modern solution to today's networking challenges". Network World.
- "Pigeon". flypigeon.co. Retrieved 2020-11-05.
- Mell, Peter; Grance, Tim (Sep 28, 2011). "The NIST Definition of Cloud Computing" – via csrc.nist.gov.
- "Solar Energy as a Service: Risk Free Solar Energy for All". Amplus Solar. Feb 14, 2017.
- "Guide to Cloud Storage Providers". www.enterprisestorageforum.com.
- Dude, Some (Nov 2, 2019). "What Is XaaS?". Some Dude Says.