Difference between revisions of "FileDriverSpec"

Latest revision as of 23:31, 17 February 2013

• Launchpad Entry: NovaSpec:filedriver
• Created: 2011-02-08
• Contributors: Christian Berendt

Summary

Implementation of a file based volume driver to manage images created by and creating with qemu-img, for example on a mounted NFS export.

Release Note

• no code provided for a release at the moment, so no release notes

Rationale

•  ??? what should i write here ???

User stories

• often there are existing big filers only accessible per NFS and not per iSCSI

Assumptions

• storage is already mounted on the system, it should not be mounted by the driver
• storage is readable and writable by the nova-volume process
• storage is mounted, readable and writable on all compute nodes
  • for example by using NFS or OCFS2
• it's possible to use more than one mountpoint to storage the images
• it's possible to specify the used format

Design

• at the moment "local" storage can only be used by using LVM2

Implementation

• check if the specified storage is correctly mounted and writable before creating a new image
• create a new images with qemu-img
• remove images with rm
  • mabye better to use a Python library here
• check needed free storage on the storage with df
  • mabye better to use a Python library here
• add a new FLAG to set the default format
• add a new FLAG to specify one or more mountpoints to be used to store new images
• add the possibility to import already created images as a new volume
  • useful for migrating and using existing images into/in the cloud
• add the possibility to choose the used format per volume
• add the possibility to choose the used mountpoint per volume
• add the possibility to move one image from a mountpoint to an other one

UI Changes

• add a new list in the dashboard to choose the format to use by newly created volume

Code Changes

• create new method FileDriver() in nova/volume/driver.py implementing the points described unter Implementation

Migration

• I don't know if it's possible at the momentan to use 2 volume drivers in one Nova setup
  • if it's possible there has to be implemented a method to migrate from and to migrate to a file image

Test/Demo Plan

This need not be added or completed until the specification is nearing beta.

Unresolved issues

• no implementation at the moment, so there are no unresolved issues

BoF agenda and discussion

• no discussion at the moment