[Kubernetes] Pod 란?

Pod 란?

• 컨테이너를 표현하는 k8s API의 최소 단위
• Pod에는 하나 또는 여러개의 컨테이너가 포함될 수 있음

Pod yaml을 이용하여 생성 (nginx-pod.yaml)

apiVersion: v1
kind: Pod
metadata:
  name: nginx-pod
spec:
  containers:
  - name: nginx-container
    image: nginx:1.14
    ports:
    - containerPort: 80
      protocol: TCP

 

Pod 실행

# kubectl create -f nginx-pod.yaml
pod/nginx-pod created

 

현재 동작중인 Pod 확인

# kubectl get pods
NAME        READY   STATUS    RESTARTS   AGE
nginx-pod   1/1     Running   0          30m

# kubectl get pods -o wide
NAME        READY   STATUS    RESTARTS   AGE   IP          NODE                NOMINATED NODE   READINESS GATES
nginx-pod   1/1     Running   0          31m   10.36.0.1   node1.example.com   <none>           <none>

 

Pod 상세 정보 확인

# kubectl describe pod nginx-pod 
Name:             nginx-pod
Namespace:        default
Priority:         0
Service Account:  default
Node:             node1.example.com/10.100.0.101
Start Time:       Thu, 24 Nov 2022 21:10:38 +0900
Labels:           <none>
Annotations:      <none>
Status:           Running
IP:               10.36.0.1
IPs:
  IP:  10.36.0.1
Containers:
  nginx-container:
    Container ID:   containerd://3a195ee94f7e6ee83f7d7db56259777151038f0ede08f1ba444dbaff5adeb8f0
    Image:          nginx:1.14
    Image ID:       docker.io/library/nginx@sha256:f7988fb6c02e0ce69257d9bd9cf37ae20a60f1df7563c3a2a6abe24160306b8d
    Port:           80/TCP
    Host Port:      0/TCP
    State:          Running
      Started:      Thu, 24 Nov 2022 21:10:52 +0900
    Ready:          True
    Restart Count:  0
    Environment:    <none>
    Mounts:
      /var/run/secrets/kubernetes.io/serviceaccount from kube-api-access-4v5v5 (ro)
Conditions:
  Type              Status
  Initialized       True 
  Ready             True 
  ContainersReady   True 
  PodScheduled      True 
Volumes:
  kube-api-access-4v5v5:
    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
  ----    ------     ----  ----               -------
  Normal  Scheduled  33m   default-scheduler  Successfully assigned default/nginx-pod to node1.example.com
  Normal  Pulling    33m   kubelet            Pulling image "nginx:1.14"
  Normal  Pulled     32m   kubelet            Successfully pulled image "nginx:1.14" in 11.567076187s
  Normal  Created    32m   kubelet            Created container nginx-container
  Normal  Started    32m   kubelet            Started container nginx-container

 

Pod 로그 확인

# kubectl logs nginx-pod
10.32.0.1 - - [24/Nov/2022:12:34:39 +0000] "GET / HTTP/1.1" 200 612 "-" "curl/7.68.0" "-"
10.32.0.1 - - [24/Nov/2022:12:34:40 +0000] "GET / HTTP/1.1" 200 612 "-" "curl/7.68.0" "-"

 

Pod 컨테이너 접속

Single Pod
# kubectl exec nginx-pod -it -- /bin/bash

Multi Pod
# kubectl exec nginx-pod -c nginx-container -it -- /bin/bash

※ multi-container pod에서 container들의 pod명과 ip는 동일 

 

 

[참고]

- https://www.youtube.com/watch?v=0rYt3PcggzA