Kubernetes concepts

The platform glossary.
Without the jargon.

Concise explanations of the building blocks used to deploy, connect, secure and operate Kubernetes workloads.

Pod

The smallest deployable Kubernetes unit. A pod runs one or more tightly coupled containers sharing network and storage context.

Deployment

A controller for stateless applications that manages ReplicaSets, rolling updates and rollback.

StatefulSet

A workload controller for applications requiring stable identities, ordered rollout or persistent storage.

DaemonSet

Ensures a pod runs on every eligible node, commonly used for agents, networking and telemetry.

Service

A stable virtual endpoint that selects pods and provides internal or external network access.

Ingress

An API for routing external HTTP and HTTPS traffic into services, implemented by an ingress controller.

Gateway API

A newer, expressive Kubernetes traffic-management API supporting role separation and advanced routing.

ConfigMap

Stores non-sensitive configuration that workloads can consume as environment variables or files.

Secret

Stores sensitive values, although production platforms should add encryption and external secret management.

Namespace

A logical boundary used for organisation, access control, policies, quotas and ownership.

RBAC

Role-based access control defines which users or service accounts may perform actions on Kubernetes resources.

NetworkPolicy

Defines allowed pod network flows when enforced by a compatible container network implementation.

PersistentVolume

A cluster storage resource supplied statically or dynamically by a storage class.

PersistentVolumeClaim

A workload request for storage with a specified capacity and access mode.

Custom Resource Definition

Extends the Kubernetes API with new resource types managed by controllers or operators.

Operator

A controller that encodes application-specific operational knowledge into reconciliation logic.

Admission Controller

Validates or changes API requests before resources are persisted, enabling policy and security controls.

Helm

A packaging and templating tool used to install and manage groups of Kubernetes resources.