CNCF Glossary

A pod is the most basic deployable unit in a Kubernetes environment. It represents a building block for deploying containerized applications, containing a single application instance and one or more containers. Kubernetes manages and scales pods vertically or horizontally.

A Service Mesh is a dedicated infrastructure layer used in microservices architectures to manage network communication between services. It addresses the inherent unreliability and security risks of computer networks by providing reliability, observability, and security features uniformly across all services without requiring changes to the application code. This prevents the need to manually encode networking logic into every individual service, reducing technical debt and development friction.

Multitenancy is a software architecture where a single installation serves multiple 'tenants' (users, applications, or groups). Each tenant operates on its own isolated data set and is generally unaware of other tenants unless explicitly configured otherwise.

Virtualization is the process of enabling a single physical server to run multiple isolated operating systems. These isolated environments, along with their dedicated compute resources (CPU, memory, and network), are called Virtual Machines (VMs). A VM is a software-defined computer that shares physical hardware with other VMs while appearing and acting as a standalone machine. This technology is the primary driver of cloud computing services, such as those provided by AWS.

Event streaming is a software architecture approach where services continuously broadcast event data (representing activities or state changes) to other subscribing applications in near real-time. Unlike traditional request-response patterns (e.g., single TCP requests) which require creating a new connection for every single piece of data, event streaming opens a connection once and allows a continuous flow of events. This decouples the source service from the receiver, as the source simply broadcasts its activities without needing to know how the information is consumed.

A node is a computer that works in concert with other nodes to accomplish a common task. In cloud computing, a node can be a physical computer, a virtual machine (VM), or a container.

Event-driven architecture is a software architecture focused on the creation, processing, and consumption of events. An event is defined as any change to an application's state. This structure allows events to be routed from their source to the appropriate receivers in real-time.

Kubernetes is an open-source container orchestrator that automates the lifecycle of containerized applications. It acts as a 'datacenter operating system,' scheduling containers across nodes and managing resources like load balancers and persistent storage.

WebAssembly (Wasm) is a binary instruction format and low-level bytecode that serves as a portable compilation target for high-level languages like C, C++, and Rust. It can be executed in a virtual machine (typically in browsers) and is used for both client-side and server-side applications, as well as in IoT environments.

Tightly coupled architecture is a style where application components are highly interdependent. A change in one component typically impacts others. While easier to implement initially, this architecture is more susceptible to cascading failures and often requires coordinated rollouts of multiple components.

Service discovery is the process of locating individual instances of a service in a dynamic cloud-native architecture. Because containerized apps frequently start, stop, and change addresses, service discovery tools track the current endpoints to ensure communication remains possible.

Portability is a software characteristic that allows an application to work across different operating environments (e.g., different cloud providers, operating systems, or vendors) without requiring major rework, thereby avoiding vendor lock-in.