sebgl / k8s-localflex-provisioner

Kubernetes Dynamic Volume Provisioning using FlexVolume to provision Local Volumes

Kubernetes Flexvolume Provisioner and Driver

NOTE: This solution is a proof of concept and will be replaced once k8s can dynamically provision local-storage.

Suggestions for improvements and Pull Requests highly welcome!

The Provisioner and Flexvolume Driver are able to create dynamic local-storage for k8s.

The Provisioner creates and empty PV with a Flexvolume Driver definition which is then called by kubelet and creates a local folder which is linked into the pod volume folder on the node. The node-affinity annotation is then updated to ensure node affinity if a pod is restarted. On deletion the PVs are deleted in k8s but not on the filesystem.

Usage:

Create a DaemonSet which deploys the flexvolume driver (these pods will be kept in an endless loop so that k8s doesn't restart them)

kubectl create -f deployment/daemonset.yaml

Make sure that $HOME/.kube/config exists on each node. This is needed so that the driver can update the PV with the node affinity annotation. Config is available when running kubectl config view. For example (on the nodes itself):

mkdir -p $HOME/.kube && cat > $HOME/.kube/config <<EOF
apiVersion: v1
clusters: 
- cluster:
    insecure-skip-tls-verify: true
    server: kube-master:8080
contexts: []
current-context: ""
kind: Config
preferences: {}
users: []
EOF

Replace kube-master:8080 with correct master IP and port if necessary.

Create the provisioner deployment

kubectl create -f deployment/deployment.yaml

Create the StorageClass with correct path to local-storage. You can define if the node-affinity alpha annotation should be used (feature-gates need to be set PersistentLocalVolumes=true,VolumeScheduling=true,MountPropagation=true)

kubectl create -f deployment/storageclass.yaml

Test

kubectl create -f - <<EOF
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: local-test
spec:
  accessModes:
    - ReadWriteMany
  resources:
    requests:
      storage: 1Mi
  storageClassName: localflex
EOF