Bug 1062022 - [RFE][nova]: Copy-on-write cloning for rbd-backed disks
Summary: [RFE][nova]: Copy-on-write cloning for rbd-backed disks
Alias: None
Product: Red Hat OpenStack
Classification: Red Hat
Component: openstack-nova
Version: unspecified
Hardware: Unspecified
OS: Unspecified
Target Milestone: z3
: 5.0 (RHEL 7)
Assignee: Pádraig Brady
QA Contact: Yogev Rabl
URL: https://blueprints.launchpad.net/nova...
Whiteboard: upstream_milestone_juno-3 upstream_de...
: 1123171 1158177 1158186 1158189 1158191 1158196 1158198 1158698 1158699 1158703 1160407 (view as bug list)
Depends On: 1166033
Blocks: rhelosp_ceph_integration 1152637 1154159 1158178 1158198 1160408 1163445
TreeView+ depends on / blocked
Reported: 2014-02-06 05:01 UTC by RHOS Integration
Modified: 2019-09-09 15:21 UTC (History)
14 users (show)

Fixed In Version: openstack-nova-2014.1.3-7.el6ost openstack-nova-2014.1.3-7.el7ost
Doc Type: Enhancement
Doc Text:
Copy-on-Write cloning for RBD-backed disks is now supported. As such, the Compute service no longer needs to download a glance image to local disk and then copy it again to RBD. Rather, disks can now be efficiently created directly in the Ceph system, thereby speeding up the creation of instances and, in the process, saving bandwidth and disk space.
Clone Of:
Last Closed: 2014-12-02 15:14:10 UTC
Target Upstream Version:

Attachments (Terms of Use)

System ID Private Priority Status Summary Last Updated
OpenStack gerrit 94293 0 None None None Never
OpenStack gerrit 94294 0 None None None Never
OpenStack gerrit 94295 0 None None None Never
Red Hat Product Errata RHBA-2014:1932 0 normal SHIPPED_LIVE openstack-nova bug fix update 2014-12-02 20:13:06 UTC

Description RHOS Integration 2014-02-06 05:01:02 UTC
Cloned from launchpad blueprint https://blueprints.launchpad.net/nova/+spec/rbd-clone-image-handler.


Currently rbd-backed ephemeral disks are created by downloading an image from glance to a local file, then uploading that file into rbd. Even if the file is cached. uploading may take a long time, since 'rbd import' is synchronous and slow. If the image is stored in rbd already by glance, there's no need for any local copies - it can be cloned to a new image for a new disk without copying the data at all.

The image handler framework enables transfering an image from glance to an abstract backend, not just a local file, so use that to implement cloning by adding a handler that detects when rbd is in use by both nova and glance, and creates a copy-on-write clone instead of downloading the image to a file.

Specification URL (additional information):


Comment 1 Pádraig Brady 2014-06-20 15:25:11 UTC
This performance enhancement missed icehouse, so proposing for 5.0.z backport

The current patches associated with this are:

  refactor libvirt RBD utilities to a new file

  use library instead of CLI to cleanup RBD volumes

  enable cloning for rbd-backed ephemeral disks

Comment 2 Abel Lopez 2014-10-13 17:52:32 UTC
Also need to track https://bugs.launchpad.net/nova/+bug/1346525 as snapshots of instances that use RBD unnecessarily download the image first, then upload to glance.

Comment 3 Pádraig Brady 2014-10-30 13:21:17 UTC
*** Bug 1158698 has been marked as a duplicate of this bug. ***

Comment 4 Pádraig Brady 2014-10-30 13:30:31 UTC
*** Bug 1158699 has been marked as a duplicate of this bug. ***

Comment 5 Pádraig Brady 2014-10-30 13:32:23 UTC
*** Bug 1158703 has been marked as a duplicate of this bug. ***

Comment 6 Pádraig Brady 2014-10-30 14:15:21 UTC
*** Bug 1158186 has been marked as a duplicate of this bug. ***

Comment 7 Pádraig Brady 2014-10-30 14:35:07 UTC
*** Bug 1158191 has been marked as a duplicate of this bug. ***

Comment 8 Pádraig Brady 2014-10-30 14:50:01 UTC
For reference an icehouse branch with these patches is at https://github.com/angdraug/nova/tree/rbd-ephemeral-clone-stable-icehouse

Comment 9 Pádraig Brady 2014-10-30 14:51:14 UTC
*** Bug 1158196 has been marked as a duplicate of this bug. ***

Comment 10 Pádraig Brady 2014-11-12 22:54:47 UTC
Abel I'm separating out https://review.openstack.org/#/c/125963/ 
(https://blueprints.launchpad.net/nova/+spec/implement-rbd-snapshots-instead-of-qemu-snapshots) to bug 1163521 as it's a separate blueprint upstream, which has not been approved yet, and also needs a corresponding change to glance.

Comment 11 Pádraig Brady 2014-11-13 11:12:43 UTC
*** Bug 1158177 has been marked as a duplicate of this bug. ***

Comment 12 Pádraig Brady 2014-11-13 11:29:22 UTC
*** Bug 1158189 has been marked as a duplicate of this bug. ***

Comment 13 Pádraig Brady 2014-11-13 20:07:00 UTC
*** Bug 1160407 has been marked as a duplicate of this bug. ***

Comment 16 Yogev Rabl 2014-11-23 15:57:59 UTC
1. uploading a new image to Glance (using rbd store)
2. launching a new instance from the newly uploaded image 
3. checked the space used in the Ceph - no additional space is been used.

Comment 18 Joe Donohue 2014-11-25 20:58:21 UTC
*** Bug 1158198 has been marked as a duplicate of this bug. ***

Comment 20 errata-xmlrpc 2014-12-02 15:14:10 UTC
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.


Comment 21 Pádraig Brady 2014-12-04 13:01:24 UTC
*** Bug 1123171 has been marked as a duplicate of this bug. ***

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