Revert "Remove quota_class db API calls"

This reverts commit 9c285c4bc777141edc80c6a40a3e1ff491aae217.

The quota_classes API was used to set default quota values
so it shouldn't have been removed, so reverting a series
of changes that removed the API and it's internal code.

Related mailing list thread on the topic:

http://lists.openstack.org/pipermail/openstack-dev/2014-May/035383.html

Partial-Bug: #1299517

Change-Id: I69e374cd0363bb7481c5bc96f1ba6415ac50fa81
Revert "Remove quota_class params from rest of nova.quota"

This reverts commit d1442a6aec5e1e20cb35627b77739dbe92770e7a.

The quota_classes API was used to set default quota values
so it shouldn't have been removed, so reverting a series
of changes that removed the API and it's internal code.

Related mailing list thread on the topic:

http://lists.openstack.org/pipermail/openstack-dev/2014-May/035383.html

Partial-Bug: #1299517

Change-Id: I839bb6570f5c189e04e284eda8cde7bc2ac29fdb
libvirt: remove redundant 'libvirt_' prefix in test case names

All the virt driver tests were moved into subdirectories
which are separate for each virt driver. There is thus no
reason to still have 'libvirt_' as a prefix in the filename
too.

A further problem with the current naming is that if you
want to just run the 'test_libvirt' test, a substring match
on that will also pick up other test suites (eg it will match
test_libvirt_config) and run those too. The renaming ensures
that no test name is a valid prefix for another test name,
making it easier to specify exactly which test file you want
run.

Change-Id: I9fe3dee5d7b7b834de84b719cab993969e34d16b
libvirt: merge two utils tests files

The nova/virt/libvirt/utils.py file had some of its tests in
test_utils.py and some in test_image_utils.py. Move them all
into test_utils.py, so the test filename matches the source
filename

Change-Id: I1001e1485646fc3546e86ddb25eb2d6ad8c88315
Merge "libvirt: remove redundant 'libvirt_' prefix in test case names"
Merge "libvirt: merge two utils tests files"
Merge "Revert "Remove quota_class db API calls""
Merge "Revert "Remove quota_class params from rest of nova.quota""
Improve shared storage checks for live migration

Distinguish cases that require shared instance drive and shared libvirt
instance directory. Reflect the fact that RBD backed instances have
shared instance drive (and no shared libvirt instance directory) in the
relevant conditionals.

Closes-bug: 1250751
Closes-bug: 1314526
Co-authored-by: Ryan Moe <rmoe@mirantis.com>
Co-authored-by: Yaguang Tang <yaguang.tang@canonical.com>
Signed-off-by: Dmitry Borodaenko <dborodaenko@mirantis.com>
Change-Id: I2755c59b4db736151000dae351fd776d3c15ca39
Move libvirt RBD utilities to a new file

This will make it easier to share rbd-related code with cinder and glance.
Port the applicable unit tests over from cinder.

Most of the code is lifted as-is from imagebackend to rbd_utils, resize() is
fixed to take bytes instead of KiB.

blueprint rbd-clone-image-handler
Co-Authored-By: Dmitry Borodaenko <dborodaenko@mirantis.com>
Signed-off-by: Josh Durgin <josh.durgin@inktank.com>
Signed-off-by: Dmitry Borodaenko <dborodaenko@mirantis.com>
Change-Id: I614b8e2bf0ea9e71a73772cbabcf812b39fa8a34
Use library instead of CLI to cleanup RBD volumes

'rbd list' CLI returns error code when there are no rbd volumes, which
causes problems during live migration of VMs with RBD backed ephemeral
volumes. It's safer to use the library that only raises an exception in
case of a real problem.

The only case where rbd CLI is still justified is import, which is
needed to correctly import sparse image files.

All code related to cleanup of RBD volumes is moved to rbd_utils.py,
this fixes a yo-yo problem with single-use methods scattered across 3
different files, and minimizes impact of this fix on imports in
imagebackend and utils.

blueprint rbd-clone-image-handler
Change-Id: I92cd6b16fbd93b377fe47b15d22efbbf68d02513
Signed-off-by: Dmitry Borodaenko <dborodaenko@mirantis.com>
enable cloning for rbd-backed ephemeral disks

Currently when using rbd as an image backend, nova downloads the
glance image to local disk and then copies it again into rbd. This
can be very slow for large images, and wastes bandwidth as well as
disk space.

When the glance image is stored in the same ceph cluster, the data is
being pulled out and pushed back in unnecessarily. Instead, create a
copy-on-write clone of the image. This is fast, and does not depend
on the size of the image. Instead of taking minutes, booting takes
seconds, and is not limited by the disk copy.

Add some rbd utility functions from cinder to support cloning and
let the rbd imagebackend rely on librbd instead of the rbd
command line tool for checking image existence.

Add a direct_fetch() method to the image backend, so backends like rbd
can make optimizations like this. Try to use direct_fetch() for the root
disk when it comes from an image, but fall back to fetch_to_raw() if
direct_fetch() fails.

Instead of calling disk.get_disk_size() directly from
verify_base_size(), which assumes the disk is stored locally, add a new
method that is overridden by the Rbd subclass to get the disk size.

Implements: blueprint rbd-clone-image-handler
Closes-Bug: 1226351
Co-Authored-By: Josh Durgin <josh.durgin@inktank.com>
Signed-Off-By: Josh Durgin <josh.durgin@inktank.com>
Signed-Off-By: Zhi Yan Liu <zhiyanl@cn.ibm.com>
Signed-Off-By: Dmitry Borodaenko <dborodaenko@mirantis.com>
Change-Id: I0f50659b54a92fc21086990be8925ea15008569a