🏏

10.(211110)쿠버네티스 Pod 실습하기

실험환경

vmware로 저번에 만든 master를 실행함

window pc

server1@master:~$ mkdir yaml
server1@master:~$ cd yaml/
server1@master:~/yaml$ gedit go-http-pod.yaml
server1@master:~/yaml$ kubectl create -f go-http-pod.yaml
pod/http-go created
server1@master:~/yaml$ ^C
server1@master:~/yaml$
YAML
복사

•

mkdir yaml : yaml 이라는 이름의 파일 생성

•

cd yaml : yaml 폴더 안에 들어가기

•

gedit go-http-pod.yaml : go-http-pod.yaml 파일을 생성하고 편집기 실행

•

go-http-pod.yaml 파일내용은 다음과 같다.

apiVersion: v1
kind: Pod
metadata:
  name: http-go
spec:
  containers:
  - name: http-go
    image: gasbugs/htttp-go
    ports:
    - containerPort: 80
YAML
복사

•

metadata:
  name: http-go 의 의미는 pod 의 이름이 http-go 이다.

•

containers:
  - name: http-go 의 의미는 컨테이너의 이름이 http-go이다. (pod이름과 동일해도 상관없음)

•

image: gasbugs/http-go 의 의미는 gasbugs/htttp-go를 실행하는 것이다. (ex : image: nginx:1.14.2)

•

kubectl create -f go-http-pod.yaml 의 의미는 우리가 만든 yaml 파일을 실행하는 것이다.

다음단계

•

pod 조회

◦

kubectl get pod [pod 이름]

◦

예시

server1@master:~/yaml$ kubectl get pod http-go
NAME      READY   STATUS    RESTARTS   AGE
http-go   0/1     Pending   0          10s
server1@master:~/yaml
YAML
복사

•

정확한 pod 조회

◦

kubectl get pod http-go -o wide

server1@master:~/yaml$ kubectl get pod http-go -o wide
NAME      READY   STATUS    RESTARTS   AGE     IP       NODE     NOMINATED NODE   READINESS GATES
http-go   0/1     Pending   0          2m51s   <none>   <none>   <none>           <none>
server1@master:~/yaml$
YAML
복사

•

pod의 자세한 내용을 yaml로 보려고 할때

server1@master:~/yaml$ kubectl get pod http-go -o yaml
apiVersion: v1
kind: Pod
metadata:
  creationTimestamp: "2021-11-10T11:09:10Z"
  name: http-go
  namespace: default
  resourceVersion: "339367"
  uid: b3eb308b-a4ac-4215-85de-e2cc17025e06
spec:
  containers:
  - image: gasbugs/htttp-go
    imagePullPolicy: Always
    name: http-go
    ports:
    - containerPort: 80
      protocol: TCP
    resources: {}
    terminationMessagePath: /dev/termination-log
    terminationMessagePolicy: File
    volumeMounts:
    - mountPath: /var/run/secrets/kubernetes.io/serviceaccount
      name: kube-api-access-b8fq6
      readOnly: true
  dnsPolicy: ClusterFirst
  enableServiceLinks: true
  preemptionPolicy: PreemptLowerPriority
  priority: 0
  restartPolicy: Always
  schedulerName: default-scheduler
  securityContext: {}
  serviceAccount: default
  serviceAccountName: default
  terminationGracePeriodSeconds: 30
  tolerations:
  - effect: NoExecute
    key: node.kubernetes.io/not-ready
    operator: Exists
    tolerationSeconds: 300
  - effect: NoExecute
    key: node.kubernetes.io/unreachable
    operator: Exists
    tolerationSeconds: 300
  volumes:
  - name: kube-api-access-b8fq6
    projected:
      defaultMode: 420
      sources:
      - serviceAccountToken:
          expirationSeconds: 3607
          path: token
      - configMap:
          items:
          - key: ca.crt
            path: ca.crt
          name: kube-root-ca.crt
      - downwardAPI:
          items:
          - fieldRef:
              apiVersion: v1
              fieldPath: metadata.namespace
            path: namespace
status:
  conditions:
  - lastProbeTime: null
    lastTransitionTime: "2021-11-10T11:09:10Z"
    message: '0/3 nodes are available: 1 node(s) had taint {node-role.kubernetes.io/master:
      }, that the pod didn''t tolerate, 2 node(s) had taint {node.kubernetes.io/unreachable:
      }, that the pod didn''t tolerate.'
    reason: Unschedulable
    status: "False"
    type: PodScheduled
  phase: Pending
  qosClass: BestEffort
server1@master:~/yaml$
YAML
복사

•

kubectl describe pod http-go

server1@master:~/yaml$ kubectl describe pod http-go
Name:         http-go
Namespace:    default
Priority:     0
Node:         <none>
Labels:       <none>
Annotations:  <none>
Status:       Pending
IP:           
IPs:          <none>
Containers:
  http-go:
    Image:        gasbugs/htttp-go
    Port:         80/TCP
    Host Port:    0/TCP
    Environment:  <none>
    Mounts:
      /var/run/secrets/kubernetes.io/serviceaccount from kube-api-access-b8fq6 (ro)
Conditions:
  Type           Status
  PodScheduled   False 
Volumes:
  kube-api-access-b8fq6:
    Type:                    Projected (a volume that contains injected data from multiple sources)
    TokenExpirationSeconds:  3607
    ConfigMapName:           kube-root-ca.crt
    ConfigMapOptional:       <nil>
    DownwardAPI:             true
QoS Class:                   BestEffort
Node-Selectors:              <none>
Tolerations:                 node.kubernetes.io/not-ready:NoExecute op=Exists for 300s
                             node.kubernetes.io/unreachable:NoExecute op=Exists for 300s
Events:
  Type     Reason            Age                 From               Message
  ----     ------            ----                ----               -------
  Warning  FailedScheduling  24s (x11 over 10m)  default-scheduler  0/3 nodes are available: 1 node(s) had taint {node-role.kubernetes.io/master: }, that the pod didn't tolerate, 2 node(s) had taint {node.kubernetes.io/unreachable: }, that the pod didn't tolerate.
server1@master:~/yaml$
YAML
복사

•

컨테이너에서 호스트로 포트포워딩

•

kubectl port-forward http-go 8080 :8080

server1@master:~/yaml$ kubectl port-forward http-go 8080 :8080
error: unable to forward port because pod is not running. Current status=Pending
server1@master:~/yaml$
YAML
복사

•

Pending 상태라서 일단 다른 예제로 한번 또 해보겠음

또다른 예제

•

gedit nginx-glory.yaml 입력

server1@master:~/yaml$ gedit nginx-glory.yaml
server1@master:~/yaml$
YAML
복사

•

아래의 yaml 소스 넣기 (nginx 예제)

apiVersion: v1
kind: Pod
metadata:
  name: nginx
spec:
  containers:
  - name: nginx
    image: nginx:1.14.2
    ports:
    - containerPort: 80
YAML
복사

•

kubectl create -f nginx-glory.yaml 입력

•

kubectl get pod nginx

server1@master:~/yaml$ gedit nginx-glory.yaml
server1@master:~/yaml$ kubectl create -f nginx-glory.yaml
pod/nginx created
server1@master:~/yaml$ kubectl get pod nginx
NAME    READY   STATUS    RESTARTS   AGE
nginx   0/1     Pending   0          56s
server1@master:~/yaml$
YAML
복사

•

어? 이것도 pending이 뜨네

•

네트워크 상에 문제가 있는것 같은데 describe 로 원인을 찾아보도록 하겠다