lizardfs-flexvolume

This Kubernetes FlexVolume driver aims to provide an implementation for provisioning LizardFS volumes to a Kubernetes POD resource.

You shouldn't use this driver in production.

Installation

FlexVolumes drivers are pretty straightforward to install :

cp lizardfs /usr/libexec/kubernetes/kubelet-plugins/volume/exec/lowet84~lizardfs/
chmod +x /usr/libexec/kubernetes/kubelet-plugins/volume/exec/lowet84~lizardfs/lizardfs

Then proceed to restart the Kubelet service

Obviously you'd need to have a functional running LizardFS cluster reachable by the Kubernetes minions.

This drivers uses the jq binary on your minions in order to parse JSON options sent by the controller. Ensure jq is installed on your minion's system coreos/bugs#1706

apt-get install -y jq

If you'd want to use the provided YML example files in order to test the feature :

kubectl create -f examples/provision-volumes.yml

Three PersistentVolumes should be created plus one PVC, bound to one of your PVs (could be any of those 3) :

kubectl get pv
NAME           CAPACITY   ACCESSMODES   RECLAIMPOLICY   STATUS      CLAIM                                   STORAGECLASS   REASON    AGE
mfs-volume     100Gi      RWX           Retain          Bound       default/test-1                                                   3h
mfs-volume-1   100Gi      RWX           Retain          Available                                                                    3h
mfs-volume-2   100Gi      RWX           Retain          Available                                                                    3h

Then proceed with a basic POD creation using this PVC test-1 :

kubectl create -f examples/deployment-using-lizardfs.yml

Kubernetes 1.6.X specific instructions

Beware, if you're running the 1.6.X branch of Kubernetes, FlexVolume drivers without an implementation of attach/detach/waitforattach (like this one, or any other driver using a networked file system) will fail

https://github.com/kubernetes/kubernetes/commit/d021db82045af0e55200a943b7db7fa71c558d2e

Either you should :

• Wait for the next Kubernetes official release
• Compile Kubernetes against master (you shouldn't for production purposes)
• Disable enable-controller-attach-detach on Kubelet startup : --enable-controller-attach-detach=false

Please follow last advice only if not running any other driver (out-of-tree or Kubernetes Integrated) needing this feature (FC, iSCSI..)

TO DO :

        # Okay, I want to provision the folder in the root of my LizardFS : each pod bound to a PVC bound to a PV has a folder created (folder name is the PV name bound to the PVC)
        # Obvisouly you need to have a fuse mountpoint on /mnt pointing to the root of your LizardFS.
        # TO DO : Automated quickmount -> mkdir -> unmount so all the logic is embedded in the flexvolume driver.
        mkdir -p /mnt/$LFSFOLDER

This FlexVolume driver tries to make a new directory in the root of your lizardfs, prealably mounted in /mnt. The goal of that behavior is to keep a folder structure matching the PersistentVolume names that were bound to the PersistentVolumeClaim.

CREDITS

https://github.com/lowet84 for the first implementation as seen on lizardfs/lizardfs#486