======
ubuntu
======

Use Ubuntu cloud images as the baseline for built disk images.

Overrides:

 * To use a non-default URL for downloading base Ubuntu cloud images,
   use the environment variable ``DIB_CLOUD_IMAGES``
 * To download a non-default release of Ubuntu cloud images, use the
   environment variable ``DIB_RELEASE``. This element will export the
   ``DIB_RELEASE`` variable.
 * Use ``DIB_DISTRIBUTION_MIRROR`` to override the ``sources.list``
   with an alternative mirror
 * Setting ``DIB_DISTRIBUTION_MIRROR_UBUNTU_IGNORE`` to an
   extended-regexp (i.e. the argument to the ``=~`` bash comparitor)
   which, when matched, will *not* set that line to the
   ``DIB_DISTRIBUTION_MIRROR``.  For example, if your local mirror
   does not mirror the universe and multiverse components, set this to
   ``(universe|multiverse)``
 * Setting ``DIB_DISTRIBUTION_MIRROR_UBUNTU_INSECURE`` updates apt
   settings to allow insecure/unuthenticated repositories.

.. element_deps::