K8S 使用downward API获取pod相关信息

参考链接：
https://kubernetes.io/docs/tasks/inject-data-application/environment-variable-expose-pod-information/

https://kubernetes.io/docs/tasks/inject-data-application/downward-api-volume-expose-pod-information/

K8S中获取pod相关信息的方式：
1、环境变量
2、volume挂载文件

[root@hanyu-210 ~]# cat pod.yaml
apiVersion: v1
kind: Pod
metadata:
  name: busybox-pod
spec:
  containers:
    - name: busybox-container
      image: busybox
      command: [ "/bin/sh", "-c", "sleep 1000" ]
      resources:
        requests:
          memory: "32Mi"
          cpu: "125m"
      env:
      - name: status.podIP
        valueFrom:
          fieldRef:
            fieldPath: status.podIP
      - name: spec.nodeName
        valueFrom:
          fieldRef:
            fieldPath: spec.nodeName
      - name: status.hostIP
        valueFrom:
          fieldRef:
            fieldPath: status.hostIP
      - name: spec.serviceAccountName
        valueFrom:
          fieldRef:
            fieldPath: spec.serviceAccountName
      - name: metadata.name
        valueFrom:
          fieldRef:
            fieldPath: metadata.name
      - name: requests.cpu
        valueFrom:
          resourceFieldRef:
            containerName: busybox-container
            resource: requests.cpu
      - name: limits.cpu
        valueFrom:
          resourceFieldRef:
            containerName: busybox-container
            resource: limits.cpu
      - name: requests.memory
        valueFrom:
          resourceFieldRef:
            containerName: busybox-container
            resource: requests.memory
      - name: limits.memory
        valueFrom:
          resourceFieldRef:
            containerName: busybox-container
            resource: limits.memory
      volumeMounts:
      - name: podinfo
        mountPath: /etc/podinfo
  volumes:
    - name: podinfo
      downwardAPI:
        items:
          - path: "labels"
            fieldRef:
              fieldPath: metadata.labels
          - path: "annotations"
            fieldRef:
              fieldPath: metadata.annotations
          - path: "cpu_limit"
            resourceFieldRef:
              containerName: busybox-container
              resource: limits.cpu
              divisor: 1m
          - path: "cpu_request"
            resourceFieldRef:
              containerName: busybox-container
              resource: requests.cpu
              divisor: 1m
          - path: "mem_limit"
            resourceFieldRef:
              containerName: busybox-container
              resource: limits.memory
              divisor: 1Mi
          - path: "mem_request"
            resourceFieldRef:
              containerName: busybox-container
              resource: requests.memory
              divisor: 1Mi
  restartPolicy: Never

kubectl apply -f pod.yaml后待pod Running后