home

[CKA] 001. Start about kubernetes

First Step for CKA

hpyYh
January 14, 2026
2 min read

ETCD : key value store

sotre data : etcdctl pub key1 value1
get data : etcdctl get key1
kubectl get pod <- use etcd

Kube-apiserver

Authentication User
Validate Request
Retrieve data
Update ETCD
Scheduler
Kubelet
work order
1. kubectl <-> kube-apiserver <-> etcd
2. kube-scheduler : monitoring kube-apiserver to choose worke
3. kube-apiserver -> kubelet -> create pod -> kube-api -> etcd

kube-controller-manager

watch status
remediate situation
ex) node connect -> kube-apiserver -> node monitoring

kube-scheduler

only chose node to locate pod
really create pod -> kubelet
filter -> score rank -> bind

kubelet

it’s present on every node
register node
create pod
Monitor Node & Pod

kube-proxy

it’s present on every node
for pod network
look for new service
use iptables rules

Pod

this is capsule for container
minimum deployable unit
able to contain one or more containers

Pod With YAML

Using YAML for create deployment, service, pv, pvc …
essential value : apiVersion, kind, metadata, spec
```
apiVersion: 
kind: 
metadata:
spec:
```
- apiVersion : v1(pod, service), apps/v1(replicaset, deployment)
- kind : Pod, Service, Deployment …
- metadata : name, namespace, labels … (dictionary type)
- spec
  - containers (list)
kubectl describe pod : detail info

How to Yaml (demo)

vim pod.yaml

apiVersion: v1
kind: Pod
metadata:
    name: nginx
    labels:
        app: nginx
        tier: fronted
spec:
    containers:
    - name: nginx
      image: nginx

kubectl apply -f pod.yaml

tags :
Cka