k8s报错：unknown: Are you trying to

背景：一个.net的微服务，使用k8s方式部署。先将配置文件以configmap形式发布

[root@k8s-master0 dc-stg-ns]# cat tidssettings.yml 
apiVersion: v1
kind: ConfigMap
metadata:
  name: tidssettings
  namespace: dc-stg-ns
data:
  tidssettings.json: |
    {
        "Logging": {
            "LogLevel": {
                "Default": "Information",
                "Microsoft": "Warning",
                "Microsoft.Hosting.Lifetime": "Information"
            }
        },
        "AllowedHosts": "*",
        "ConnectionStrings": {
                     .................（略）
        }
    }

再配置应用及服务

apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    k8s-app: xxxx-xxxx
  name: xxxx-xxxx
  namespace: dc-stg-ns
spec:
  replicas: 2
  selector:
    matchLabels:
      k8s-app: xxxx-xxxx
  strategy:
    rollingUpdate:
      maxSurge: 0
      maxUnavailable: 1
    type: RollingUpdate
  template:
    metadata:
      creationTimestamp: null
      labels:
        k8s-app: xxxx-xxxx
    spec:
      affinity:
        podAntiAffinity:
          requiredDuringSchedulingIgnoredDuringExecution:
            - labelSelector:
                matchLabels:
                  k8s-app: xxxx-xxxx
              topologyKey: kubernetes.io/hostname
      containers: 
        - env: 
          - name: APP_OPTIONS
            value: '-Xms1024m -Xmx1024m -Xss1024k'
          volumeMounts:
            - mountPath: /app/appsettings.json
              name: tidssettingsapp
              readOnly: true
              subPath: appsettings.json  
          image: 192.168.xx.xx:8082/xxxx-xxxx:202209300656
          imagePullPolicy: IfNotPresent
          name: xxxx-xxxx
          ports:
            - containerPort: 80
              protocol: TCP
          readinessProbe:
            failureThreshold: 3
            initialDelaySeconds: 60
            periodSeconds: 10
            successThreshold: 1
            tcpSocket:
              port: 80
            timeoutSeconds: 1    
      volumes:
        - configMap:
            defaultMode: 420
            name: tidssettings
          name: tidssettingsapp  
      imagePullSecrets:
      - name: docker-pull-secret  

---
apiVersion: v1
kind: Service
metadata:
  labels:
    k8s-app: xxxx-xxxx
  name: xxxx-xxxx
  namespace: dc-stg-ns
spec:
  ports:
    - name: http-80
      nodePort: 30224
      port: 30224
      protocol: TCP
      targetPort: 80
  selector:
    k8s-app: xxxx-xxxx
  sessionAffinity: None
  type: NodePort      

在部署应用后，一直提示出错：Error......unknown: Are you trying to mount a directory onto a file (or vice-versa)? Check if the specified host path exists and is the expected type
看网上的说法大都不靠谱，最后发现问题出在这一行：subPath: appsettings.json
这里subpath是指的源文件，而实际上这里的configmap源文件为：tidssettings.json
因此，改为subPath: tidssettings.json 后故障消除
我们也可以在这里查看这个CM

[root@k8s-master0 dc-stg-ns]# kg  cm tidssettings  -n dc-stg-ns -o yaml
apiVersion: v1
data:
  tidssettings.json: |
    {
        "Logging": {
            "LogLevel": {
                "Default": "Information",
                "Microsoft": "Warning",
                "Microsoft.Hosting.Lifetime": "Information"
            }
......

从这里也可以看到，要挂载的配置文件名为 tidssettings.json