Stream raw images

[Lucas Alvares Gomes]

IPA always cache the image under /tmp and then copy it to the disk. While this is required for images using some disk format such as qcow2 that requires it to be converted before it's copied to the disk (due the need of random access in the image file), the same doesn't hold true for raw disk images.

For raw disks images the image could be downloaded and copied onto de disk directly without the need of caching it before, this would be faster and would require less memory to run the ramdisk.

Also, checksum can be computed from the stream and verified at the end of the process.

[OpenStack Infra (hudson-openstack)]

Related fix proposed to branch: master
Review: https://review.openstack.org/234338

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/234339

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/234338
Committed: https://git.openstack.org/cgit/openstack/ironic-python-agent/commit/?id=65053b7737ffe9641974df926d694efd801ba417
Submitter: Jenkins
Branch: master

commit 65053b7737ffe9641974df926d694efd801ba417
Author: Lucas Alvares Gomes <email address hidden>
Date: Tue Oct 13 17:10:37 2015 +0100

    Refactor the image download and checksum computation bits

    Prior to this patch downloading and computing the checksum of the image
    were done in different stages, after the download the file would need
    to be re-read and the checksum was computed. This patch is changing it
    by creating a ImageDownload class which computes the checksum at the same
    time the image is being downloaded, this saves time and also make the
    code more portable.

    Related-Bug: #1505685
    Change-Id: I71f9f2bd9a62a6a6cc474d0ae519591cea6381d6

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/234339
Committed: https://git.openstack.org/cgit/openstack/ironic-python-agent/commit/?id=e320bb8942f6737969ed58e732de26bdcb528a84
Submitter: Jenkins
Branch: master

commit e320bb8942f6737969ed58e732de26bdcb528a84
Author: Lucas Alvares Gomes <email address hidden>
Date: Tue Oct 13 17:31:46 2015 +0100

    Add support for streaming raw images directly onto the disk

    This patch adds support for streaming a raw image directly onto the disk,
    that means no more time spent writing the image to a tmpfs partition prior
    to copying it to the disk. Checksum computation is also done as the image
    is being streamed. Streaming raw images is disabled by default, however
    this behavior can be enabled by passing a key called "stream_raw_images"
    with the value of True to the prepare_image() command of IPA.

    For non-raw images this may not be possible, not sure about all image
    file formats, but common types such as qcow2 requires random access to
    the image file in order to be converted to raw.

    Closes-Bug: #1505685
    Change-Id: Iddf67907bc9b54bbd3065a97064cb5a3602cfe18

[Doug Hellmann (doug-hellmann)]

This issue was fixed in the openstack/ironic-python-agent 1.1.0 release.