The choise of which CSI provider to use depends heavily on the use case and infrastructure you're running on and the use case you have.
Bundled OpenEBS storage#
K0s comes out with bundled OpenEBS installation which can be enabled by using configuration file
Use following configuration as an example:
spec: extensions: storage: type: openebs_local_storage
The cluster will have two storage classes available for you to use:
k0s kubectl get storageclass
NAME PROVISIONER RECLAIMPOLICY VOLUMEBINDINGMODE ALLOWVOLUMEEXPANSION AGE openebs-device openebs.io/local Delete WaitForFirstConsumer false 24s openebs-hostpath openebs.io/local Delete WaitForFirstConsumer false 24s
openebs-hostpath is the storage class that maps to the
Use following manifests as an example of pod with mounted volume:
apiVersion: v1 kind: PersistentVolumeClaim metadata: name: nginx-pvc namespace: default spec: accessModes: - ReadWriteOnce storageClassName: openebs-hostpath resources: requests: storage: 5Gi --- apiVersion: apps/v1 kind: Deployment metadata: name: nginx namespace: default labels: app: nginx spec: selector: matchLabels: app: nginx strategy: type: Recreate template: metadata: labels: app: nginx spec: containers: - image: nginx name: nginx volumeMounts: - name: persistent-storage mountPath: /var/lib/nginx volumes: - name: persistent-storage persistentVolumeClaim: claimName: nginx-pvc
k0s kubectl apply -f nginx.yaml
persistentvolumeclaim/nginx-pvc created deployment.apps/nginx created bash-5.1# k0s kc get pods NAME READY STATUS RESTARTS AGE nginx-d95bcb7db-gzsdt 1/1 Running 0 30s
k0s kubectl get pv
NAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS REASON AGE pvc-9a7fae2d-eb03-42c3-aaa9-1a807d5df12f 5Gi RWO Delete Bound default/nginx-pvc openebs-hostpath 30s
k0s supports a wide range of different storage options by utilizing Container Storage Interface (CSI). All Kubernetes storage solutions are supported and users can easily select the storage that fits best for their needs.
When the storage solution implements Container Storage Interface (CSI), containers can communicate with the storage for creation and configuration of persistent volumes. This makes it easy to dynamically provision the requested volumes. It also expands the supported storage solutions from the previous generation, in-tree volume plugins. More information about the CSI concept is described on the Kubernetes Blog.
Installing 3rd party storage solutions#
Follow your storage driver's installation instructions. Note that the Kubelet installed by k0s uses a slightly different path for its working directory (
/varlib/k0s/kubelet instead of
/var/lib/kubelet). Consult the CSI driver's configuration documentation on how to customize this path.
Example storage solutions#
Different Kubernetes storage solutions are explained in the official Kubernetes storage documentation. All of them can be used with k0s. Here are some popular ones:
- Rook-Ceph (Open Source)
- MinIO (Open Source)
- Gluster (Open Source)
- Longhorn (Open Source)
- Amazon EBS
- Google Persistent Disk
- Azure Disk
If you are looking for a fault-tolerant storage with data replication, you can find a k0s tutorial for configuring Ceph storage with Rook in here.