os/config/cloudinit/Documentation/config-drive.md

Distribution via Config Drive

CoreOS supports providing configuration data via config drive disk images. Currently only providing a single script or cloud config file is supported.

Contents and Format

The image should be a single FAT or ISO9660 file system with the label config-2 and the configuration data should be located at openstack/latest/user_data.

For example, to wrap up a config named user_data in a config drive image:

mkdir -p /tmp/new-drive/openstack/latest
cp user_data /tmp/new-drive/openstack/latest/user_data
mkisofs -R -V config-2 -o configdrive.iso /tmp/new-drive
rm -r /tmp/new-drive

If on OS X, replace the mkisofs invocation with:

hdiutil makehybrid -iso -joliet -default-volume-name config-2 -o configdrive.iso /tmp/new-drive

QEMU virtfs

One exception to the above, when using QEMU it is possible to skip creating an image and use a plain directory containing the same contents:

qemu-system-x86_64 \
    -fsdev local,id=conf,security_model=none,readonly,path=/tmp/new-drive \
    -device virtio-9p-pci,fsdev=conf,mount_tag=config-2 \
    [usual qemu options here...]