provisioner/

README

local-volume-provisioner

quay.io/external-storage/local-volume-provisioner:1.0.0

local-volume-provisioner is an out-of-tree static provisioner for the local volume plugin, which is a 1.7 & 1.8 alpha feature.

It runs on each node in the cluster and monitors specified directories to look for new local file-based volumes. The volumes can be a mount point or a directory in a shared filesystem. It then statically creates a Local PersistentVolume for each local volume. It also monitors when the PersistentVolumes have been released, and will clean up the volume, and recreate the PV.

Changelog

Development

Compile the provisioner

make

Make the container image and push to the registry

make push

Design

There is one provisioner instance on each node in the cluster. Each instance is reponsible for monitoring and managing the local volumes on its node.

The basic components of the provisioner are as follows:

• Discovery: The discovery routine periodically reads the configured discovery directories and looks for new mount points that don't have a PV, and creates a PV for it.

• Deleter: The deleter routine is invoked by the Informer when a PV phase changes. If the phase is Released, then it cleans up the volume and deletes the PV API object.

• Cache: A central cache stores all the Local PersistentVolumes that the provisioner has created. It is populated by a PV informer that filters out the PVs that belong to this node and have been created by this provisioner. It is used by the Discovery and Deleter routines to get the existing PVs.

• Controller: The controller runs a sync loop that coordinates the other components. The discovery and deleter run serially to simplify synchronization with the cache and create/delete operations.