Use squashfs for more recent Ubuntu releases

[Valery Tschopp]

The diskimage-builder fails to create Ubuntu 18.04 Bionic image.

The command:

   DIB_RELEASE=bionic disk-image-create vm ubuntu

Fails because it can not download the non existing http://cloud-images.ubuntu.com/bionic/current/bionic-server-cloudimg-amd64-root.tar.gz filesystem tarball for Ubuntu Bionic.

Tested with the latest (master) diskimage-builder version

Log file is attached.

[Valery Tschopp (valery-tschopp)]

Bug https://bugs.launchpad.net/cloud-images/+bug/1585233 can be related.

[Dan Watkins (oddbloke)]

In an effort to reduce the number of images that we publish on cloud-images.ubuntu.com, we condensed our kernel-less root images to just the squashfs between xenial and bionic (because it can be used directly as a partition for use cases that require that).

Ideally, diskimage-builder would learn how to cache and unpack the squashfs for releases for which it is provided.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/569103

[Stanislav Makar (smakar)]

Related bug https://bugs.launchpad.net/cloud-images/+bug/1660983

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/569103
Committed: https://git.openstack.org/cgit/openstack/diskimage-builder/commit/?id=2e6a19a018197f1f9dda54763e65b06e5ad16d1a
Submitter: Zuul
Branch: master

commit 2e6a19a018197f1f9dda54763e65b06e5ad16d1a
Author: Stanislav Makar <email address hidden>
Date: Tue May 15 10:42:31 2018 +0000

    Add Ubuntu 18.04 support

    Use squashfs for more recent Ubuntu releases

    Change-Id: I80df28be6e2a5e03ae1450e84fc05715f21a7750
    Closes-bug: 1766850