Kubernetes Architecture: Beyond the Basics

You know Pods and Services. But to run K8s in production, you need to understand the Control Plane, Etcd consistency, and the Scheduler’s decision-making process.

Control Plane Internals

flowchart TB
    subgraph ControlPlane ["Control Plane"]
        API[API Server]
        Etcd[(Etcd)]
        Sched[Scheduler]
        CM[Controller Manager]
    end
    
    subgraph Node ["Worker Node"]
        Kubelet
        Proxy[Kube-Proxy]
        Pod
    end
    
    API <--> Etcd
    API <--> Sched
    API <--> CM
    API <--> Kubelet
    
    style ControlPlane fill:#E1F5FE,stroke:#0277BD

The Reconciliation Loop

Kubernetes is basically a set of infinite loops checking `Current State == Desired State`. If not, it acts.

# Desired State
apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx
spec:
  replicas: 3 # The goal

Key Takeaways

• **Etcd** is the brain; back it up.
• **API Server** is the only component that talks to Etcd.
• **Kubelet** is the captain of the node ship.