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Persistence

there are currently 3 types of storage:

nfs: shared file system

File volumes behave like docker host mounts and are fully managed for you including redundancy and backups. They can be accessed by multiple pods simultaneously and support concurrent read/writes to some degree. This is useful for configs and other shared data that doesn't have high performance requirements. Since the intent is to emulate docker volume behavior, this is the default choice if you don't know which volume type you need.

lv2: local nvme

LV2 is exposed as block storage to the vm. Usually it will be automatically formated and mounted as ext4 but can also be used as raw block device available in /dev/volumes/ by not specifying any volumeMounts. Note that directly attached storage is not highly available. In case of a host failure there's a manual recovery process involved that will be executed whenever the host is back. users of lv2 should prepare for that scenario.

creating your first volume

docker supports volumes natively, and the cli works out of the box

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docker volume create example --driver nfs
docker run -v example:/data -ti ubuntu

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root@warmhearted_snow:/# mount | grep /data
/dev/vdc on /data type ext4 (rw,nodev,relatime)
root@warmhearted_snow:/# df -h | grep data
/dev/volumes/example  9.8G   28K  9.3G   1% /data

k8s uses PersistentVolumeClaim to create volumes

example.yaml
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---
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: postgres
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 100G
  storageClassName: block
---
apiVersion: v1
kind: Pod
metadata:
  name: postgres
spec:
  containers:
  - name:  postgres
    image: postgres
    volumeMounts:
    - mountPath: /var/lib/postgresql/data
      name: postgres
  volumes:
  - name: postgres
    persistentVolumeClaim:
      claimName: postgres
---

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kubectl apply -f example.yaml

docker supports volumes natively, and the compose spec works out of the box

docker-compose.yaml
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version: "3.9"
volumes:
  - example
services:
  nginx:
    image: ubuntu
    volumes:
      - example:/data

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docker volume create example
docker compose up -d
docker volume inspect example

docker supports volumes natively, and the compose spec works out of the box

docker-compose.yaml
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version: "3.9"
volumes:
  - example
services:
  nginx:
    image: ubuntu
    volumes:
      - example:/data

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docker stack deploy -c ./docker-compose.yaml mystack
docker volume inspect example

WebDAV Access

volumes can be accessed via webdav via https://files.kraudcloud.com or davs://files.kraudcloud.com depending on your client.

You will find username/password in your profile under "Files Login".