[kubernetes] 쿠버네티스 볼륨(Volume) - emptyDir 볼륨

쿠버네티스 볼륨(Volume)

사용 사능한 볼륨 목록

• emptyDir
  임시로 데이터를 저장하는 빈 볼륨(디렉터리)
• gitRepo
  내부적으로 emptyDir 기능을 이용하여 초기에 git 리포지토리의 내용을 채워서 제공하는 볼륨. 더 이상 사용되지 않음(Deprecated)
• hostPath
  쿠버네티스 클러스터 노드(호스트)의 파일 시스템을 제공하는 볼륨
• 네트워크 스토리지 볼륨
  nfs, cinder, cephfs, iscsi, glusterfs, quobyte, rbd, flexVolume, vsphereVolume, photonPersistentDisk
• 클라우드 스토리지 볼륨
  gcePersistentDisk(GCE Persistent Disk), awsElasticBlockStore(AWS EBS Volume), azureDist(MS Azure Disk Volume)
• 정적/동적 프로비저닝 볼륨
  persistentVolumeClaim
• 특수 유형 볼륨
  configMap, secret, downwardAPI

원본URL-https://www.msaschool.io/assets/static/image17.711609e.ce1e16e79c278514e5baca0d5e02bb41.png

emptyDir 볼륨

emptyDir 볼륨 생성

emptyDir1.yaml 파일 작성

apiVersion: apps/v1
kind: ReplicaSet
metadata:
  name: myapp-rs-fortune
spec:
  replicas: 1
  selector:
    matchLabels:
      app: myapp-rs-fortune
  template:
    metadata:
      labels:
        app: myapp-rs-fortune
    spec:
      containers:
        - name: web-server
          image: nginx:alpine
          volumeMounts:
            - name: web-fortune
              mountPath: /usr/share/nginx/html
              readOnly: true
          ports:
            - containerPort: 80
              protocol: TCP
        - name: html-generator
          image: ghcr.io/c1t1d0s7/fortune
          volumeMounts:
            - name: web-fortune
              mountPath: /var/htdocs

      volumes:
        - name: web-fortune
          emptyDir: {}

emptyDir1-svc.yaml 파일 작성

apiVersion: v1
kind: Service
metadata:
  name: myapp-svc-fortune
spec:
  selector:
    app: myapp-rs-fortune
  ports:
  - port: 80
    targetPort: 80

 

kubectl create -f emptyDir1.yaml -f emptyDir1-svc.yaml

 

kubectl get all

$ kubectl get all
NAME                         READY   STATUS    RESTARTS   AGE
pod/myapp-rs-fortune-szsvx   2/2     Running   0          5m12s

NAME                        TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)   AGE
service/kubernetes          ClusterIP   10.233.0.1      <none>        443/TCP   2d22h
service/myapp-svc-fortune   ClusterIP   10.233.18.172   <none>        80/TCP    15m

NAME                               DESIRED   CURRENT   READY   AGE
replicaset.apps/myapp-rs-fortune   1         1         1       5m12s

$ curl 10.233.18.172
Delay not, Caesar.  Read it instantly.
		-- Shakespeare, "Julius Caesar" 3,1

Here is a letter, read it at your leisure.
		-- Shakespeare, "Merchant of Venice" 5,1

	[Quoted in "VMS Internals and Data Structures", V4.4, when
	 referring to I/O system services.]

 

kubectl describe pods myapp-rs-fortune-szsvx

$ kubectl describe pods myapp-rs-fortune-szsvx
Name:         myapp-rs-fortune-szsvx
Namespace:    default
Priority:     0
Node:         kube-node2/192.168.56.22
Start Time:   Mon, 10 Oct 2022 21:15:07 +0900
Labels:       app=myapp-rs-fortune
Annotations:  cni.projectcalico.org/containerID: d283c73f18888dd7e6d6f662d21545636a67f4b13672ab4f83d5340388969f59
              cni.projectcalico.org/podIP: 10.233.74.12/32
              cni.projectcalico.org/podIPs: 10.233.74.12/32
Status:       Running
IP:           10.233.74.12
IPs:
  IP:           10.233.74.12
Controlled By:  ReplicaSet/myapp-rs-fortune
Containers:
  web-server:
    Container ID:   docker://3eb112432b707a4fb08e7f99106d2f4e9458ece426c59082d4b1a9242e290561
    Image:          nginx:alpine
    Image ID:       docker-pullable://nginx@sha256:b87c350e6c69e0dc7069093dcda226c4430f3836682af4f649f2af9e9b5f1c74
    Port:           80/TCP
    Host Port:      0/TCP
    State:          Running
      Started:      Mon, 10 Oct 2022 21:15:08 +0900
    Ready:          True
    Restart Count:  0
    Environment:    <none>
    Mounts:
      /usr/share/nginx/html from web-fortune (ro)
      /var/run/secrets/kubernetes.io/serviceaccount from kube-api-access-zqldt (ro)
  html-generator:
    Container ID:   docker://0e4148c711512bb83e98d2edf5f0256e31cf76d9ac92290ca52222d5c2c8dabc
    Image:          ghcr.io/c1t1d0s7/fortune
    Image ID:       docker-pullable://ghcr.io/c1t1d0s7/fortune@sha256:7f2d656f90921b2cb94faeac0798fe8bca94e91d85fb8c1d335866b16c581eec
    Port:           <none>
    Host Port:      <none>
    State:          Running
      Started:      Mon, 10 Oct 2022 21:15:21 +0900
    Ready:          True
    Restart Count:  0
    Environment:    <none>
    Mounts:
      /var/htdocs from web-fortune (rw)
      /var/run/secrets/kubernetes.io/serviceaccount from kube-api-access-zqldt (ro)
...

 

kubectl exec myapp-rs-fortune-szsvx -c web-server -- cat /usr/share/nginx/html/index.html

$ kubectl exec myapp-rs-fortune-szsvx -c web-server -- cat /usr/share/nginx/html/index.html
You will live a long, healthy, happy life and make bags of money.

 

참고URL

- 임시 볼륨 : https://kubernetes.io/ko/docs/concepts/storage/ephemeral-volumes/

- MSA School : https://www.msaschool.io/operation/operation/operation-two/