Glossary

Glossary

This glossary defines some of the most common Kubernetes-related terms used in the course.

Term: Definition

• Admission controller: It is a code that validates or mutates resources to enforce policies. It runs as part of the API admission chain immediately after authentication and authorization.

• Annotation: It is object metadata that can be used to expose alpha or beta capabilities or integrate with third-party systems.

• API: It stands for Application Programming Interface. In Kubernetes, all resources are defined in the API, which is RESTful and exposed via the API server.

• API group: It is a set of related API resources. For example, networking resources are usually located in the networking.k8s.io API group.

• API resource: All Kubernetes objects, such as Pods, Deployments, and Services, are defined in the API as resources.

• API server: It exposes the API on a secure port over HTTPS. It runs on the control plane.

• Cloud controller manager: It is a control plane service that integrates with the underlying cloud platform. For example, when creating a LoadBalancer Service, the cloud controller manager implements the logic to provision one of the underlying cloud’s internet-facing load balancers.

• Cloud-native: It is a loaded term that means different things to different people. Cloud-native is a way of designing, building, and working with modern applications and infrastructure. We personally consider an application cloud-native if it can self-heal, scale on-demand, perform rolling updates, and possibly rollbacks.

• Cluster: It is a set of worker and control plane nodes that work together to run user applications.

• Cluster store: It is a control plane feature that holds the state of the cluster and apps. Typically, it is based on the etcd distributed data store and runs on the control plane. It can be deployed to its own cluster for higher performance and higher availability.

• ConfigMap: It is a Kubernetes object used to hold non-sensitive configuration data. It is a great way to add custom configuration data to a generic container at runtime without editing the image.

• Container: It is a lightweight environment for running modern apps. Each container is a virtual operating system with its own process tree, filesystem, ...