[CKA][실습] 1. Core Concepts (2)

CKA 취득을 위해 Kodecloud의 CKA 실습 내용을 정리한 글 입니다.

 

Practice Test - Namespaces

$ alias k=kubectl
$ k get ns
$ k get po -n research
#특정 ns에 pod 생성
$ k run redis --image=redis -n finance
$ k get po -A

기타 :

• 같은 namespace내의 service를 호출할 때는 service 이름만으로 가능
• 다른 namaspace의 service를 호출할 때는 FQDN으로 가능

<service-name>.<namespace>.svc.cluster.local

 

---

Practice Test - Services

$ k get svc
## service의 label 확인
$ k label svc kubernetes --list=true

sample yaml 파일 활용하여 svc 생성하기

---
apiVersion: v1
kind: Service
metadata:
  name: webapp-service
spec:
  type: NodePort
  ports:
    - targetPort: 8080
      port: 8080
      nodePort: 30080
  selector:
    name: simple-webapp

• port : service의 port
• targetPort : pod의 port
• nodePort: node의 port

---

Practice Test - Imperative Commands

$ k run nginx-pod --image=nginx:alpine

## label 지정하여 pod 생성
$ k run --help | grep label
  # Start a hazelcast pod and set labels "app=hazelcast" and "env=prod" in the container
  kubectl run hazelcast --image=hazelcast/hazelcast --labels="app=hazelcast,env=prod"
    -l, --labels='':
        Comma separated labels to apply to the pod. Will override previous values.
        
$ k run redis --image=redis:alpine --labels="tier=db"
## pod label 확인
$ k label po redis --list=true

## pod expose하는 service 생성
$ kubectl expose pod redis --port=6379 --name redis-service

## port 지정하여 pod 생성
$ k run -h | grep port
  # Start a hazelcast pod and let the container expose port 5701
  kubectl run hazelcast --image=hazelcast/hazelcast --port=5701
        If true, create a ClusterIP service associated with the pod.  Requires `--port`.
    --port='':
        The port that this container exposes.
  kubectl run NAME --image=image [--env="key=value"] [--port=port] [--dry-run=server|client] [--overrides=inline-json] [--command] -- [COMMAND] [args...] [options]

$ k run custom-nginx --image=nginx --port=8080
  
$ k create ns dev-ns
$ k create deploy redis-deploy -n dev-ns --image=redis --replicas=2

## pod 생성 후 svc로 expose
$ k run httpd --image=httpd
$ k expose po httpd --port=80 --port=80 --cluster-ip='' --name=httpd