New Question

Vfat config drive format support

asked 2014-10-23 03:21:17 +0300

alrick gravatar image

updated 2014-10-23 03:22:38 +0300

In Piston OpenStack we use config_drive_format=vfat to prevent data loss during instance block migrations (because libvirt does not block migrate virtual cdrom devices), but current cloud-init release supports only iso9660 config drive format.

Do you have plans to add vfat support as well in the future?

Thanks in advance.

edit retag flag offensive close merge delete

1 answer

Sort by » oldest newest most voted

answered 2014-10-23 11:42:02 +0300

alexpilotti gravatar image

The issue is that the VFAT config drive is a so called RAW partition (e.g. on Linux you'd mount it directly as /dev/sdb, not /dev/sdb1) and this is not supported by Windows, where a partitioning scheme is required (e.g. MBR) in order to mount a partition.

What we can do is to extract the raw block data from the disk, put them in a vfd file and mount that as a loopback device (Windows 2008 R2 / Windows 7 and above). Being this a non trivial implementation we always left it as a low priority feature request due to the availability of the ISO option.

Note: the libvirt (KVM) live migration issue with config drives has been fixed in Juno:

This bug fix is worth a backporting to Icehouse as well IMO.

edit flag offensive delete link more


Thank you very much for the answer!

alrick gravatar imagealrick ( 2014-10-23 23:29:31 +0300 )edit

I have some good news. Incidentally we're working on another project which involves VFAT images and it looks like I have a solution for this. Would you be interested in beta testing it?

alexpilotti gravatar imagealexpilotti ( 2014-10-24 01:21:42 +0300 )edit

Thanks for the update! Sure we would like to take a look at the solution.

alrick gravatar imagealrick ( 2014-10-24 01:33:25 +0300 )edit

FYI, we have VFAT ConfigDrive support since march.

cpopa gravatar imagecpopa ( 2015-04-06 20:07:07 +0300 )edit

Your Answer

Please start posting anonymously - your entry will be published after you log in or create a new account.

Add Answer

Question Tools

1 follower


Asked: 2014-10-23 03:21:17 +0300

Seen: 834 times

Last updated: Oct 23 '14