What Is the CKA? Glossary & Key Terms

CKA
Certified Kubernetes Administrator — a hands-on, performance-based certification from the Cloud Native Computing Foundation validating skills to install, configure, and manage production Kubernetes clusters.
Pod
The smallest deployable unit in Kubernetes, consisting of one or more containers that share networking and storage and are scheduled together on the same node.
kube-apiserver
The Kubernetes control-plane component that exposes the REST API, validates requests, and serves as the central hub through which all cluster interactions pass.
etcd
A distributed, consistent key-value store used as Kubernetes' backing store for all cluster state and configuration data.
kube-scheduler
The control-plane component that assigns newly created Pods to nodes based on resource availability, constraints, and scheduling policies.
kube-controller-manager
The control-plane process that runs controller loops responsible for reconciling actual cluster state with desired state (e.g., node, replication, and endpoint controllers).
kubelet
The node agent running on every worker node that ensures containers defined in PodSpecs are running as expected and reports status to the control plane.
kube-proxy
A network proxy running on each node that implements Kubernetes Service networking rules, enabling communication to and between Pods.
Deployment
A Kubernetes controller object that manages ReplicaSets to provide declarative updates, rolling deployments, and rollback capability for stateless applications.
ReplicaSet
A controller that maintains a stable set of a specified number of identical Pod replicas running at any given time.
StatefulSet
A controller for managing stateful applications that require stable network identities, persistent storage, and ordered deployment/scaling/termination.
DaemonSet
A controller that ensures a copy of a specific Pod runs on all (or a selected subset of) nodes in the cluster.
Service
An abstraction that defines a stable network endpoint and load-balances traffic to a dynamic set of Pods matched by label selectors.
Ingress
An API object that manages external HTTP/HTTPS access to cluster Services, typically providing routing rules and TLS termination via an Ingress controller.
ConfigMap
A Kubernetes object used to store non-confidential configuration data as key-value pairs, consumable by Pods as environment variables or mounted files.
Secret
A Kubernetes object for storing sensitive data such as passwords, tokens, or keys, base64-encoded and access-restricted separately from ConfigMaps.
PersistentVolume (PV)
A piece of storage provisioned in the cluster, either statically by an administrator or dynamically via a StorageClass, independent of any individual Pod's lifecycle.
PersistentVolumeClaim (PVC)
A user's request for storage that binds to a matching PersistentVolume, letting Pods consume storage without needing to know its underlying implementation.
StorageClass
A resource that defines a category of storage with a specific provisioner and parameters, enabling on-demand dynamic provisioning of PersistentVolumes.
Namespace
A logical partition within a Kubernetes cluster used to isolate and organize groups of resources, commonly by team, project, or environment.
Taint
A property applied to a node that repels Pods from being scheduled onto it unless those Pods have a matching toleration.
Toleration
A Pod-level setting that allows (but does not require) the Pod to be scheduled onto nodes with matching taints.
NetworkPolicy
A namespace-scoped resource that defines rules governing which Pods may communicate with each other and with external endpoints, enforced by the cluster's CNI plugin.
kubeadm
The official Kubernetes CLI tool for bootstrapping control-plane nodes, joining worker nodes to a cluster, and performing cluster upgrades.