Basics

Component	Simple Definition
Deployment	Manages stateless applications by maintaining a desired number of Pods with rolling updates.
StatefulSet	Manages stateful applications, giving each Pod a unique, persistent identity and storage.
DaemonSet	Ensures a copy of a Pod runs on every node (or a subset), often used for system daemons.
Job	Runs Pods to completion for one-time or batch tasks.
CronJob	Schedules Jobs to run at specified times, like a cron job.
Service	Provides a stable network endpoint (IP/DNS) for accessing a set of Pods.
Ingress	Manages external HTTP/S traffic and routes it to Services based on rules.
ConfigMap	Stores configuration settings (non-sensitive) as key-value pairs for applications.
Secret	Stores sensitive information (passwords, API keys) in base64-encoded form.
Volume	Provides storage that containers in a Pod can use to read/write files.
PersistentVolume (PV)	Defines a piece of storage in the cluster, provisioned manually or dynamically.
PersistentVolumeClaim (PVC)	A request by a user for storage, used by Pods to connect to PVs.
Namespace	Logical separation of cluster resources to isolate environments or teams.
Horizontal Pod Autoscaler (HPA)	Automatically adjusts the number of Pods based on metrics like CPU usage.

Component	Simple Definition
Cluster	A group of machines (nodes) running Kubernetes — includes a control plane and worker nodes.
Node	A single machine (VM or physical) in the cluster — can be a control plane node or worker node.
Control Plane	Manages the Kubernetes cluster — makes global decisions and ensures the desired state.
API Server (kube-apiserver)	The front-end for the Kubernetes control plane — all interactions (via kubectl, UIs, etc.) go through it.
Controller Manager (kube-controller-manager)	Runs controllers that handle background tasks — like node monitoring, replication, and endpoint management.
Scheduler (kube-scheduler)	Decides which node a new Pod should run on, based on resource availability and policies.
etcd	A highly available key-value store used to store all cluster state and configuration data.
Cloud Controller Manager	Connects Kubernetes to your cloud provider (e.g., managing load balancers, nodes, storage).
Worker Node	Runs application workloads (Pods) and is managed by the control plane.
Kubelet	Agent that runs on every node and ensures containers are running as defined in specs.
kube-proxy	Handles network routing on each node — enables service discovery and load balancing within the cluster.
Container Runtime	The software (like containerd, Docker, CRI-O) that actually runs containers on a node.