How to map one single file into kubernetes pod using hostPath?

Try using the subPath key on your volumeMounts like this:

apiVersion: v1kind: Podmetadata:  name: singlefilespec:  containers:  - image: ubuntu    name: singlefiletest    command:      - /bin/bash      - -c      - ls -la /singlefile/ && cat /singlefile/hosts    volumeMounts:    - mountPath: /singlefile/hosts      name: etc      subPath: hosts  volumes:  - name: etc    hostPath:      path: /etc

Example:

$ kubectl apply -f singlefile.yamlpod "singlefile" created$ kubectl logs singlefiletotal 24drwxr-xr-x. 2 root root 4096 Aug  3 12:50 .drwxr-xr-x. 1 root root 4096 Aug  3 12:50 ..-rw-r--r--. 1 root root 1213 Apr 26 21:25 hosts# /etc/hosts: Local Host Database## This file describes a number of aliases-to-address mappings for the for # local hosts that share this file....

Actually it is caused by kvm which is used by minikube.

path: /home/ubuntu/workspace/web.conf

If I login to minikube, it is folder in vm.

$ ls -al /home/ubuntu/workspace # in minikube hosttotal 12drwxrwxr-x 2 ubuntu ubuntu 4096 Aug  3 12:11 .drwxrwxr-x 5 ubuntu ubuntu 4096 Aug  3 19:28 ..-rw-rw-r-- 1 ubuntu ubuntu 1184 Aug  3 12:11 web.conf$ minikube ssh$ ls -al /home/ubuntu/workspace # in minikube vmtotal 0drwxr-xr-x 3 root root 0 Aug  3 19:41 .drwxr-xr-x 4 root root 0 Aug  3 19:41 ..drwxr-xr-x 2 root root 0 Aug  3 19:41 web.conf

I don't know exactly why kvm host folder sharing behalf like this.

Therefore instead I use minikube mount command, see host_folder_mount.md, then it works as expected.