K
Q

kubernetes add local files to pod

3/6/2020

I am attempting to build a pod in kubernetes that has files mounted to the pod from my local system, in a similar way to mounting volumes in docker-compose files

I have tried the following, in an attempt to mount the local folder ./test and files to the pod under the /blah/ folder. However kubernetes is complaining that MountVolume.SetUp failed for volume "config-volume" : hostPath type check failed: ./test/ is not a directory

Here is my yaml file. Am I missing something?

kind: Service
metadata:
  name: vol-test
  labels:
    app: vol-test
spec:
  type: NodePort
  ports:
    - port: 8200
      nodePort: 30008
  selector:
    app: vol-test

---

apiVersion: apps/v1
kind: Deployment
metadata:
  name: vol-test
spec:
  replicas: 1
  selector:
    matchLabels:
      app: vol-test
  template:
    metadata:
      labels:
        app: vol-test
    spec:
      containers:
        - name: vol-test
          image: nginx
          imagePullPolicy: "IfNotPresent"
          volumeMounts:
            - name: config-volume
              mountPath: /blah/
          ports:
            - containerPort: 8200
      volumes:
        - name: config-volume
          hostPath:
            path: ./test/
            type: Directory
-- mcgowan.b
docker
kubernetes

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2 Answers

3/6/2020

you can do it like this

kind: PersistentVolume
apiVersion: v1
metadata:
  name: config-volume-pv
  labels:
    type: local
spec:
  storageClassName: generic
  capacity:
    storage: 100Mi
  accessModes:
    - ReadWriteOnce
  hostPath:
    path: "/path/to/volume"

---
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  creationTimestamp: null
  name: config-volume-pvc
spec:
  storageClassName: generic
  accessModes:
  - ReadWriteOnce
  resources:
    requests:
      storage: 100Mi
status: {}

---
kind: Service
metadata:
  name: vol-test
  labels:
    app: vol-test
spec:
  type: NodePort
  ports:
    - port: 8200
      nodePort: 30008
  selector:
    app: vol-test

---

apiVersion: apps/v1
kind: Deployment
metadata:
  name: vol-test
spec:
  replicas: 1
  selector:
    matchLabels:
      app: vol-test
  template:
    metadata:
      labels:
        app: vol-test
    spec:
      containers:
        - name: vol-test
          image: nginx
          imagePullPolicy: "IfNotPresent"
          volumeMounts:
          - mountPath: /blah/
            name: ng-data
          ports:
            - containerPort: 8200
      volumes:
      - name: ng-data
        persistentVolumeClaim:
          claimName: config-volume-pvc
-- Al-waleed Shihadeh
Source: StackOverflow
3/7/2020

If you just want to pass a file or directory to a Pod for the purpose of reading configuration values (which I assume from your choice of volume mount config-volume) and has no need to update the file/directory, then you can just put the file(s) in a ConfigMap like below:

apiVersion: v1
kind: ConfigMap
metadata:
  name: nginx-router-config
data:
  nginx.conf: |
    worker_processes 2;
    user nginx;
    events {
        worker_connections  1024;
    }

    http {
        include       mime.types;
        charset       utf-8;
        client_max_body_size 8M;

        server {
            server_name _;
            listen 80 default_server;

            location / {
                proxy_set_header Host $host;
                proxy_set_header X-Forwarded-Host $host;
                proxy_set_header X-Forwarded-Proto https;
                proxy_pass http://drupal:80/ ;
                proxy_redirect default;
            }

            location /api/ {
                proxy_pass http://api-gateway:8080/ ;
                proxy_redirect default;
            }
        }
    }

Or you can have the file content imported from where you run the kubectl command and execute (assuming the file name is nginx.conf):

kubectl create configmap nginx-router-config --from-file=nginx.conf

Then, you can mount the file(s) by adding volumes and volumeMount to the Deployment spec:

apiVersion: apps/v1beta2
kind: Deployment
metadata:
  name: nginx-router
  labels:
    app: nginx
spec:
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:latest
        ports:
        - containerPort: 80
        volumeMounts:
        - name: nginx-router-config
          mountPath: /etc/nginx/nginx.conf
          subPath: nginx.conf
      volumes:
        - name: nginx-router-config
          configMap:
            name: nginx-router-config
            items:
              - key: nginx.conf
                path: nginx.conf

If you actually want to have read-write access to the file(s) then you can use PersistentVolume and PersistentVolumeClaim as suggested by the other answer, although I will not recommend using hostPath if you have more than one worker node.

-- Lukman
Source: StackOverflow