Minikube: Files in hostPath volumes are lost after minikube restart

[vdamle]

Is this a BUG REPORT or FEATURE REQUEST? (choose one):
BUG REPORT

Please provide the following details:

Environment: Minikube on MacOS Mojave (10.14.2)

Minikube version : v0.33.1

• OS : MacOS Mojave (10.14.2)
• VM Driver : virtualbox
• ISO version : minikube-v0.29.0.iso
• Install tools: brew cask install minikube
• Others:

What happened: Files present in hostPath volumes are not persisted after restart of minikube

What you expected to happen: Files present in hostPath volumes should be persisted after restart of minikube

How to reproduce it (as minimally and precisely as possible):

• Create a pod with one or more hostPath volumes and corresponding volume mounts
• write to one or more files in the volume mount directories (one can minikube ssh and see that the files are present in the hostPath directory)
• minikube stop
• minikube start --vm-driver="virtualbox"
• The files are no longer present in the directory

Output of minikube logs (if applicable):

minikube-logs.txt

Anything else do we need to know: This was working perfectly fine until recently. I have upgraded MacOS, minikube (using brew cask), docker recently. Not sure which one could be the culprit ¯_(ツ)_/¯

[tstromberg]

Do you mind elaborating on your repro instructions? I'd like to see if this problem exists on other platforms, but am not yet familiar with hostPath volumes. Thanks!

[vdamle]

Hi @tstromberg : thanks for taking a look. I have the following volume definition in my stateful set:

      volumes:
      - hostPath:
          path: /mnt/qdata
          type: DirectoryOrCreate
        name: qdata

and one or more containers use that volume and mount it to a path inside the container:

        volumeMounts:
        - mountPath: /qdata
          name: qdata

After I start a pod with the above, the software running in the pod writes files to /qdata directory. Anytime after this, if I restart minikube (as a result of putting my macbook to sleep) and/or explicitly restarting minikube, the pod is running again, and /qdata directory shows up in the pod (and inside minikube VM), but the files which were written are not present in the directory anymore. Hope this helps.

[vdamle]

@tstromberg - Did you get a chance to look at this? do you need more info?

[afbjorklund]

Minikube will only persist host paths located under /data, not anything located under e.g. /qdata
You could of course add your own mount or symlink, to move the data over to the /dev/sda1 disk ?

The dynamically provision volumes are also persisted, but the paths should be considered internal.
Same with the other default directories, those are mostly internal to the system or to the runtime...

---

Here is the findmnt output, excluding the overlay mounts since those are even more "internal":

TARGET                SOURCE                                      FSTYPE OPTIONS
/mnt/sda1             /dev/sda1                                   ext4   rw,rela
/var/lib/boot2docker  /dev/sda1[/var/lib/boot2docker]             ext4   rw,rela
/var/lib/docker       /dev/sda1[/var/lib/docker]                  ext4   rw,rela
/var/lib/containers   /dev/sda1[/var/lib/containers]              ext4   rw,rela
/var/log              /dev/sda1[/var/log]                         ext4   rw,rela
/var/tmp              /dev/sda1[/var/tmp]                         ext4   rw,rela
/var/lib/kubelet      /dev/sda1[/var/lib/kubelet]                 ext4   rw,rela
/var/lib/cni          /dev/sda1[/var/lib/cni]                     ext4   rw,rela
/data                 /dev/sda1[/data]                            ext4   rw,rela
/tmp/hostpath_pv      /dev/sda1[/hostpath_pv]                     ext4   rw,rela
/tmp/hostpath-provisioner
                      /dev/sda1[/hostpath-provisioner]            ext4   rw,rela
/var/lib/rkt          /dev/sda1[/var/lib/rkt]                     ext4   rw,rela
/etc/rkt              /dev/sda1[/var/lib/rkt-etc]                 ext4   rw,rela
/var/lib/minikube     /dev/sda1[/var/lib/minikube]                ext4   rw,rela
/var/lib/minishift    /dev/sda1[/var/lib/minishift]               ext4   rw,rela

So the recommended location provided for persistent hostPath mounts is somewhere under /data.

See https://github.com/kubernetes/minikube/blob/master/docs/persistent_volumes.md

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[hellovietduc]

I'm having this issue. After restart I lose data in my Postgres DB. Here's the deployment.yml:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: postgres
  namespace: db
  labels:
    app: postgres
spec:
  replicas: 1
  selector:
    matchLabels:
      app: postgres
  template:
    metadata:
      labels:
        app: postgres
    spec:
      containers:
        - name: postgres
          image: postgres:11.5
          ports:
            - containerPort: 5432
          envFrom:
            - configMapRef:
                name: config-postgres
          env:
            - name: PGDATA
              value: /var/lib/postgresql/data
          volumeMounts:
            - mountPath: /var/lib/postgresql
              name: postgresdb
      volumes:
        - name: postgresdb
          persistentVolumeClaim:
            claimName: pvc-postgres

And the volumes:

apiVersion: v1
kind: PersistentVolume
metadata:
  name: minikube-pv-postgres
  namespace: db
  labels:
    app: minikube-pv-postgres
spec:
  storageClassName: standard
  accessModes:
    - ReadWriteOnce
  capacity:
    storage: 10Gi
  hostPath:
    path: /data/minikube-pv-postgres/

---
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: pvc-postgres
  namespace: db
  labels:
    app: pvc-postgres
spec:
  volumeName: minikube-pv-postgres
  storageClassName: standard
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 10Gi

The headache is I specify hostPath at /data/ directory, but the data is still lost.

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