Ramdisk for overcloud image shall include lvm, crypt drivers , or add the possibility to include extra ones

[Yolanda Robla]

When testing with whole disk images (to start using volumes and encryption on images), I had to rebuild the ramkdisk of the overcloud-full image to add modules that are quite generic, such as lvm or crypt.
Another use case that I found, is the need of having iscsi as well.

The process for building the image shall include the most used modules , and also it shall provide a mechanism for people rebuilding the images to easily customize it , to include the modules they need on demand.

[Yolanda Robla (yolanda.robla)]

I did some testing with diskimage-builder, to start using dracut instead of busybox, as this element claims. I saw that lvm and crypt modules were properly added to the ramdisk (had to install cryptsetup and lvm2 packages as well) . But the problem i see with that, is that this elements generates an independent ramdisk file, instead of updating the ramdisk used in the /boot directory.
We cannot use it in TripleO like that, because we extract initrd and vmlinuz from boot directory (or use whole disk images, just consuming the qcow2) . So that extra generated file is not consumed by TripleO, and the modules are not loaded.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/420698

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/419486
Committed: https://git.openstack.org/cgit/openstack/tripleo-image-elements/commit/?id=4c51932d2ee073fe70fd5b285b9e193cbc573911
Submitter: Jenkins
Branch: master

commit 4c51932d2ee073fe70fd5b285b9e193cbc573911
Author: Yolanda Robla Mota <email address hidden>
Date: Thu Jan 12 15:20:51 2017 +0100

    Add element to rebuild dracut enabling modules

    To support TripleO whole disk images (with enabled
    security), we need lvm and crypt modules.
    So creating that element in tripleo, that will install the
    needed packages, and will rebuild the image to add the
    modules we need.

    Change-Id: I1b0dd384a1981acffd64652708ec21323f5e795a
    Partial-Bug: #1655681

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/420698
Committed: https://git.openstack.org/cgit/openstack/tripleo-common/commit/?id=71fb1e94533e779989e0b0b40afd5bf8e8deb084
Submitter: Jenkins
Branch: master

commit 71fb1e94533e779989e0b0b40afd5bf8e8deb084
Author: Yolanda Robla Mota <email address hidden>
Date: Mon Jan 16 13:25:36 2017 +0100

    Add element to regenerate dracut

    We need to include extra modules in the overcloud, for
    supporting whole disk images and security

    Change-Id: I2a1004f37f31c99fcc4ced36a78a8501d02037a7
    Depends-On: I1b0dd384a1981acffd64652708ec21323f5e795a
    Partial-Bug: #1655681