Deploying PV in MiniKube K8S

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I am deploying a stateful application in K8S.

Before that Im trying to implement an example.

Before deploying my-sql in my cluster, I have created a pv and a pvc.

kind: PersistentVolume
apiVersion: v1
metadata:
  name: mysql-pv-volume
  labels:
    type: local
spec:
  storageClassName: manual
  capacity:
    storage: 20Gi
  accessModes:
    - ReadWriteOnce
  hostPath:
    path: "/mnt/data"
---
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: mysql-pv-claim
spec:
  storageClassName: manual
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 20Gi

At this point in time, I have not edit or created any new StorageClass.

I then go on to deploy the application using a volumeMount in my deployment.

.
.
       volumeMounts:
        - name: mysql-persistent-storage
          mountPath: /var/lib/mysql
      volumes:
      - name: mysql-persistent-storage
        persistentVolumeClaim:
          claimName: mysql-pv-claim

I bring up the application successfully and, take it down (first the pod and the the deployment) and bring back the application and notice that my application data persists under /var/lib/mysql

I later on noticed that /mnt/data does NOT exist on my host machine. I am working in minikube.

I looked into the storage class and it seems to be using :

StorageClass:    manual

But if I check all my storage classes, I see only this one :

# kubectl describe storageclass
Name:            standard
IsDefaultClass:  Yes
Annotations:     kubectl.kubernetes.io/last-applied-configuration={"apiVersion":"storage.k8s.io/v1","kind":"StorageClass","metadata":{"annotations":{"storageclass.beta.kubernetes.io/is-default-class":"true"},"labels":{"addonmanager.kubernetes.io/mode":"Reconcile"},"name":"standard","namespace":""},"provisioner":"k8s.io/minikube-hostpath"}
,storageclass.beta.kubernetes.io/is-default-class=true
Provisioner:           k8s.io/minikube-hostpath
Parameters:            <none>
AllowVolumeExpansion:  <unset>
MountOptions:          <none>
ReclaimPolicy:         Delete
VolumeBindingMode:     Immediate
Events:                <none>

But the one that my-sql is using is not there.

I need help in understanding this please. Where is the PV /mnt/data ?

On my host machine the result to look for /mnt/data is : 

# cd /mnt/data
cd: no such file or directory: /mnt/data
minikube kubernetes
1 Answers

Minikube is a Virtual Machine (VM) based all-in-one solution. So you have one node where the entire control plane lives and also this is your only worker node as well:

$ kubectl get node
NAME       STATUS  ROLES   AGE  VERSION 
minikube   Ready   master  1d   v1.10.0

Now, it's one node, a VM, that hosts your Kubernetes cluster. So all host-related actions have to be done on said VM:

$ minikube ssh
                         _             _
            _         _ ( )           ( )
  ___ ___  (_)  ___  (_)| |/')  _   _ | |_      __
/' _ ` _ `\| |/' _ `\| || , <  ( ) ( )| '_`\  /'__`\
| ( ) ( ) || || ( ) || || |\`\ | (_) || |_) )(  ___/
(_) (_) (_)(_)(_) (_)(_)(_) (_)`\___/'(_,__/'`\____)

$ ls -al /mnt
total 4
drwxr-xr-x  3 root root   60 Sep  8 12:38 .
drwxr-xr-x 17 root root  460 Sep  8 12:38 ..
drwxr-xr-x  7 root root 4096 Sep  8 12:38 vda1

And here you have your /mnt directory.

user_3965670
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