参考链接：
https://kubernetes.io/docs/concepts/storage/volumes/#using-subpath

我们知道configmap可以通过挂载文件的方式给pod使用，那如果configmap中包含多组key-value值，而用户挂载时，只需要其中一组key-value，并不想全部挂载或者想把key-value挂载到不同的目录下，那如何做呢？这时候subPath就有用武之地了。

创建configmap

apiVersion: v1
kind: ConfigMap
metadata:
  name: special-config
  namespace: default
data:
  special.level: very
  special.type: |-
    property.1=value-1
    property.2=value-2
    property.3=value-3

创建pod使用subPath

apiVersion: v1
kind: Pod
metadata:
  name: busybox-pod
spec:
  containers:
    - name: busybox-container
      image: busybox
      command: [ "/bin/sh", "-c", "sleep 1000" ]

      volumeMounts:
      - name: config-volume
        mountPath: /etc/special.type
        subPath: special.type
      - name: config-volume
        mountPath: /etc/config/special.level
        subPath: special.level
  volumes:
    - name: config-volume
      configMap:
        name: special-config
  restartPolicy: Never

观察文件挂载情况