Table of Contents

환경변수

apiVersion: v1
kind: Pod
metadata:
  name: hello-app
spec:
  containers:
  - name: hello-app-con
    image: yoonjeong/hello-app:1.0
    ports:
    - containerPort: 8080
    resources:
      limits:
        memory: "128Mi"
        cpu: "100m"

kubectl apply -f ./hello-app/pod.yaml

kubectl get pods -o wide

kubectl exec -it hello-app -- /bin/sh

env

apiVersion: v1
kind: Pod
metadata:
  name: hello-app
spec:
  containers:
  - name: hello-app-con
    image: yoonjeong/hello-app:1.0
    ports:
    - containerPort: 8080
    env:
      - name: MY_NAME
        value: "Jay"
    resources:
      limits:
        memory: "128Mi"
        cpu: "100m"

env

kubectl get pod hello-app -o json

크게 metadata, spec, status 항목이 있음

apiVersion: v1
kind: Pod
metadata:
  name: hello-app
spec:
  containers:
  - name: hello-app-con
    image: yoonjeong/hello-app:1.0
    ports:
    - containerPort: 8080
    env:
      - name: MY_NAME
        value: "Jay"
      - name: POD_IP
        valueFrom:
          fieldRef:
            fieldPath: status.podIP
      - name: NODE_IP
        valueFrom:
          fieldRef:
            fieldPath: status.hostIP
      - name: NODE_NAME
        valueFrom:
          fieldRef:
            fieldPath: spec.nodeName
    resources:
      limits:
        memory: "128Mi"
        cpu: "100m"

env

네트워크

파드내에 컨테이너끼리 통신

apiVersion: v1
kind: Pod
metadata:
  name: blue-green-app # Pod의 호스트명
spec:
  containers:
  - name: blue-app
    image: yoonjeong/blue-app:1.0
    ports:
    - containerPort: 8080
    resources:
      limits:
        memory: "64Mi"
        cpu: "100m"

kubectl apply -f blue-green-app/pod.yaml

kubectl logs blue-green-app -c blue-app

kubectl exec -it blue-green-app -c blue-app -- /bin/sh

# 블루 앱에서 그린 앱에 localhost로 통신
curl -vs localhost:8081/tree

서로 다른 파드의 컨테이너간 통신

kubectl apply -f red-app/pod.yaml

kubectl get pods -o wide

export RED_POD_IP=$(kubectl get pod red-app -o jsonpath="{.status.podIP}")

echo $RED_POD_IP
----------------------
10.100.1.3

kubectl exec blue-green-app -c blue-app -- curl -vs $RED_POD_IP:8080/rose

kubectl port-forward blue-green-app 8080:8080

URL: localhost:8080/sky

라벨링

apiVersion: v1
kind: Pod
metadata:
  name: red-app
  labels:
    category: nature
    app: rose
spec:
  containers:
  - name: red-app
    image: yoonjeong/red-app:1.0
    ports:
    - containerPort: 8080
    resources:
      limits:
        memory: "64Mi"
        cpu: "100m"

kubectl get pods --show-labels

# (라벨간에 띄어쓰기 허용 x)
kubectl get pod -L app,category

# --selector 대신 -l 써도됨
kubectl get pod --selector app=rose -L app

kubectl get pod -l 'app in (rose,sky-and-tree)' -L app

배포할 노드 지정

# 노드 목록과 레이블 확인
kubectl get nodes

# 노드에 Label 추가
# -- 첫번째, 세번째 노드에 soil=moist
# -- 두번째 노드에 soil=dry
kubectl label node <1번째 노드> <3번째 노드> soil=moist
kubectl label node <2번째 노드> soil=dry

# soil 노드 레이블 확인
kubectl get node -L soil

apiVersion: v1
kind: Pod
metadata:
  name: red-app
spec:
  nodeSelector:
    soil: moist
  containers:
  - name: red-app
    image: yoonjeong/red-app:1.0
    ports:
    - containerPort: 8080
    resources:
      limits:
        memory: "64Mi"
        cpu: "100m"