A Glossary of Key Terms in Cloud Infrastructure & Scalability

In today’s rapidly evolving business landscape, understanding the backbone of modern technology is no longer exclusive to IT departments. For HR and recruiting professionals, a grasp of cloud infrastructure and scalability concepts is crucial for making informed decisions about software solutions, data management, and the overall technological agility of their organization. As talent acquisition and HR operations increasingly rely on sophisticated platforms and automation, knowing these terms helps ensure your systems are robust, secure, and ready to grow with your company. This glossary provides essential definitions, tailored to illuminate their relevance within an HR and recruiting context.

Cloud Computing

Cloud computing refers to the on-demand availability of computer system resources—especially data storage (cloud storage) and computing power—without direct active management by the user. Instead of maintaining physical servers and infrastructure, businesses access services like servers, databases, networking, analytics, and intelligence over the internet from a cloud provider (e.g., AWS, Azure, Google Cloud). For HR, this means that HRIS, ATS, and payroll systems can be hosted externally, reducing internal IT overhead, ensuring accessibility from anywhere, and simplifying data backups. It enables HR teams to deploy new tools quickly without significant upfront hardware investments, enhancing agility in talent management and employee services.

Software as a Service (SaaS)

SaaS is a cloud-based software delivery model where a third-party provider hosts applications and makes them available to customers over the internet. Instead of installing and maintaining software, you simply access it via the web, usually on a subscription basis. This is perhaps the most familiar cloud concept for HR, as most modern HR tech—like Applicant Tracking Systems (ATS), Human Resources Information Systems (HRIS), performance management platforms, and even communication tools—are delivered as SaaS. It eliminates the need for HR teams to manage software updates, patches, or server maintenance, allowing them to focus purely on strategic HR initiatives and talent engagement.

Infrastructure as a Service (IaaS)

IaaS provides virtualized computing resources over the internet. It gives users the highest level of flexibility and management control over their cloud resources, akin to owning your own data center but without the physical hardware. Users manage operating systems, data, and applications, while the cloud provider manages the physical infrastructure. While less common for direct HR usage than SaaS, IaaS is crucial for companies that host custom-built HR applications, complex data analytics platforms, or specific automation engines (like Make.com instances for advanced HR workflows). It provides the underlying computing power and storage needed for highly customized or resource-intensive HR technology solutions.

Platform as a Service (PaaS)

PaaS provides a cloud-based environment for developing, running, and managing applications without the complexity of building and maintaining the infrastructure typically associated with developing and launching an app. It offers a complete environment to develop, run, and deploy applications. For HR, PaaS can be relevant when a company develops custom internal applications, such as a unique employee onboarding portal or a proprietary performance review tool. It simplifies the development process by handling the server-side infrastructure, databases, and operating systems, allowing developers to focus solely on the application code and features vital for HR operations.

Scalability

Scalability refers to a system’s ability to handle a growing amount of work or its potential to be enlarged to accommodate that growth. In cloud infrastructure, it means that resources can be increased or decreased dynamically based on demand. For HR, scalability is vital for any technology solution, especially in high-growth companies. An ATS must scale to handle spikes in job applications during hiring surges, and an HRIS needs to accommodate a rapidly expanding employee base without performance degradation. Cloud-based HR systems are designed for this, ensuring that resources are automatically allocated or de-allocated, preventing bottlenecks and maintaining seamless operations during periods of rapid change.

Elasticity

Elasticity is a specific characteristic of scalability in cloud computing, referring to the ability to automatically and quickly provision and de-provision computing resources to match fluctuating workload demands. Unlike general scalability, which might involve manual upgrades, elasticity implies automation and real-time adjustment. For HR, this is critical during cyclical peak times, such as open enrollment periods, annual performance reviews, or massive recruitment drives where system usage skyrockets. An elastic HR platform can seamlessly handle the sudden surge in users and data processing, then scale back down when demand subsides, optimizing costs and ensuring consistent user experience without manual intervention from IT or HR staff.

Redundancy

Redundancy in cloud infrastructure means duplicating critical components or functions of a system to ensure that if one component fails, another can take over without interruption. This is key for high availability and disaster recovery. For HR, data redundancy is paramount for safeguarding sensitive employee information and operational continuity. Imagine a payroll system or an ATS failing during a critical period; redundancy ensures that backups are immediately available, preventing data loss and minimizing downtime. This protects the integrity of HR operations, ensures compliance, and maintains employee trust by guaranteeing access to vital HR services.

Disaster Recovery (DR)

Disaster Recovery is a set of policies, tools, and procedures that enable the recovery or continuation of vital technology infrastructure and systems following a natural or human-induced disaster. In a cloud context, DR typically involves replicating data and applications across multiple geographically dispersed data centers. For HR, a robust DR plan is essential for ensuring business continuity. If a primary data center goes offline, a cloud-based HR system with DR capabilities can quickly failover to a secondary location, ensuring that critical HR functions like payroll processing, benefits administration, and applicant tracking remain operational. This minimizes disruption to employees and protects sensitive HR data from catastrophic loss.

Data Center

A data center is a facility used to house computer systems and associated components, such as telecommunications and storage systems. While cloud computing abstracts users from the physical location, data centers are the physical foundation of the cloud. They are highly secure, climate-controlled environments with redundant power, networking, and cooling. For HR, understanding that cloud services are built on these robust physical infrastructures provides assurance regarding data security, uptime, and performance. Although HR professionals don’t directly interact with data centers, knowing they exist and are professionally managed reinforces the reliability and security of their cloud-based HR software solutions.

API (Application Programming Interface)

An API is a set of definitions and protocols that allow different software applications to communicate with each other. It defines the methods and data formats that applications can use to request and exchange information. For HR and recruiting, APIs are the backbone of integration and automation. They allow an ATS to “talk” to a background check service, an HRIS to sync with a payroll system, or an onboarding platform to pull data from a CRM. Without APIs, many of the seamless, automated workflows that save HR professionals significant time and reduce manual data entry would be impossible, enabling the creation of powerful, interconnected HR tech stacks.

DevOps

DevOps is a set of practices that combines software development (Dev) and IT operations (Ops) to shorten the systems development life cycle and provide continuous delivery with high software quality. It promotes collaboration, automation, and communication between development and operations teams. While primarily a software development methodology, DevOps principles indirectly benefit HR by ensuring the rapid and reliable deployment of new features and improvements to HR software. For HR, this translates into faster access to updated tools, bug fixes, and new functionalities in their ATS, HRIS, or other platforms, ensuring that their systems remain cutting-edge and responsive to evolving business needs with minimal downtime.

Serverless Computing

Serverless computing is a cloud execution model where the cloud provider dynamically manages the allocation and provisioning of servers. Developers write and deploy code without worrying about the underlying infrastructure. The serverless model executes code only when triggered by events (e.g., a file upload, a form submission), and users only pay for the compute time consumed. For HR automation, serverless functions can be incredibly powerful for specific tasks that don’t require continuous server uptime. Examples include processing new resume uploads, triggering welcome emails upon a new hire’s status change, or automating data transformations between different HR systems, offering cost efficiency and scalability for event-driven workflows.

Hybrid Cloud

A hybrid cloud is a computing environment that combines a public cloud (e.g., AWS, Azure) with a private cloud (an on-premises data center or a private cloud hosted by a third party), allowing data and applications to be shared between them. This approach offers the flexibility of public cloud services with the enhanced security and control often associated with private infrastructure. For HR, a hybrid cloud might be used to keep highly sensitive employee data (e.g., health records, financial information) in a private cloud for regulatory compliance or enhanced security, while leveraging the public cloud for less sensitive applications like applicant tracking or general employee portals. It provides a strategic balance of control, cost, and agility.

Virtualization

Virtualization is the technology that creates a virtual (rather than actual) version of something, such as a server, storage device, network resource, or operating system. It allows a single physical hardware resource (like a server) to run multiple isolated virtual environments. This efficiency is a cornerstone of cloud computing. For HR, virtualization directly impacts the underlying infrastructure supporting cloud-based HR applications. While largely transparent to the end-user, it ensures that your HR systems are hosted efficiently, sharing resources but maintaining their own operational integrity. This leads to better resource utilization, cost savings for cloud providers (which can translate to better service pricing), and improved disaster recovery capabilities for HR data and applications.

Containerization

Containerization is a lightweight alternative to full machine virtualization, where applications are packaged into “containers” with all their necessary libraries, frameworks, and configurations. These containers can then run consistently across any environment. Unlike virtual machines, containers share the host operating system’s kernel, making them much more efficient. For HR, containerization is more relevant to the software developers and IT teams managing HR applications than to daily users. It allows for faster deployment of new HR software features, consistent performance across different servers, and greater portability of applications. This ultimately means more reliable, rapidly updated, and scalable HR tech tools that are less prone to “it worked on my machine” issues.

If you would like to read more, we recommend this article: Keap Data Protection for HR & Recruiting: Recover Data, Preserve Performance