Kubernetes Glossary

Kubernetes Glossary

A comprehensive list of terms used in the Kubernetes course.

A

API Server The central management entity that exposes the Kubernetes API. It is the front-end for the Kubernetes control plane.

ArgoCD A declarative, GitOps continuous delivery tool for Kubernetes.

C

Chart A package of pre-configured Kubernetes resources used by Helm.

Cluster A set of node machines for running containerized applications.

Container Runtime The software that is responsible for running containers (e.g., containerd, CRI-O, Docker Engine).

Control Plane The container orchestration layer that exposes the API and interfaces to define, deploy, and manage the lifecycle of containers.

Controller Manager Daemon that embeds the core control loops shipped with Kubernetes.

CRD (Custom Resource Definition) An extension mechanism that allows you to define your own object kinds in the Kubernetes API.

D

DaemonSet A workload object that ensures a copy of a Pod runs on all (or some) Nodes in the cluster.

Declarative A method of configuration where you specify the desired state, and the system works to achieve it (as opposed to Imperative).

E

Etcd Consistent and highly-available key value store used as Kubernetes’ backing store for all cluster data.

F

Fluentd An open-source data collector for unified logging layer, often used to ship logs from Kubernetes to Elasticsearch.

G

GitOps A set of practices to manage infrastructure and application configurations using Git as the single source of truth.

H

Helm The package manager for Kubernetes.

I

Imperative A method of configuration where you specify the exact steps to achieve a result.

K

Kube-proxy A network proxy that runs on each node in your cluster, implementing part of the Kubernetes Service concept.

Kubelet An agent that runs on each node in the cluster. It makes sure that containers are running in a Pod.

M

Manifest A JSON or YAML file that describes the desired state of a Kubernetes object.

N

Node A worker machine in Kubernetes (VM or physical server).

O

Operator A method of packaging, deploying, and managing a Kubernetes application. It uses a Controller and CRDs to encode human operational knowledge.

P

Pod The smallest and simplest Kubernetes object. A Pod represents a set of running containers on your cluster.

Prometheus An open-source monitoring system with a dimensional data model, flexible query language, and efficient time series database.

PromQL Prometheus Query Language, used to select and aggregate time series data in real time.

R

Raft A consensus algorithm designed to be easy to understand. It’s used by Etcd to manage a highly available replicated log.

Reconciliation Loop The process by which a controller compares the current state with the desired state and takes action to match them.

S

Scheduler Control plane component that watches for newly created Pods with no assigned node, and selects a node for them to run on.

Service An abstract way to expose an application running on a set of Pods as a network service.

Sidecar A secondary container running in the same Pod as the main application container, often used for logging, monitoring, or proxying.

T

TSDB (Time Series Database) A database optimized for storing and serving time series data (pairs of time and value), used by Prometheus.