RHEL Engineering is moving the tracking of its product development work on RHEL 6 through RHEL 9 to Red Hat Jira (issues.redhat.com). If you're a Red Hat customer, please continue to file support cases via the Red Hat customer portal. If you're not, please head to the "RHEL project" in Red Hat Jira and file new tickets here. Individual Bugzilla bugs in the statuses "NEW", "ASSIGNED", and "POST" are being migrated throughout September 2023. Bugs of Red Hat partners with an assigned Engineering Partner Manager (EPM) are migrated in late September as per pre-agreed dates. Bugs against components "kernel", "kernel-rt", and "kpatch" are only migrated if still in "NEW" or "ASSIGNED". If you cannot log in to RH Jira, please consult article #7032570. That failing, please send an e-mail to the RH Jira admins at rh-issues@redhat.com to troubleshoot your issue as a user management inquiry. The email creates a ServiceNow ticket with Red Hat. Individual Bugzilla bugs that are migrated will be moved to status "CLOSED", resolution "MIGRATED", and set with "MigratedToJIRA" in "Keywords". The link to the successor Jira issue will be found under "Links", have a little "two-footprint" icon next to it, and direct you to the "RHEL project" in Red Hat Jira (issue links are of type "https://issues.redhat.com/browse/RHEL-XXXX", where "X" is a digit). This same link will be available in a blue banner at the top of the page informing you that that bug has been migrated.
Bug 750801 - [RFE] specifying the entire image chain as a qemu drive (blockdev-add) (qemu)
Summary: [RFE] specifying the entire image chain as a qemu drive (blockdev-add) (qemu)
Keywords:
Status: CLOSED ERRATA
Alias: None
Product: Red Hat Enterprise Linux 7
Classification: Red Hat
Component: qemu-kvm-rhev
Version: 7.4
Hardware: Unspecified
OS: Unspecified
high
medium
Target Milestone: pre-dev-freeze
: 7.4
Assignee: Kevin Wolf
QA Contact: CongLi
URL:
Whiteboard:
Depends On: 1086193 1086677 1087142 1159726 1159728
Blocks: 731134 760547 773650 773651 773665 773677 773696 1231739 1289208 1395265 1469590 1558125
TreeView+ depends on / blocked
 
Reported: 2011-11-02 12:03 UTC by Saggi Mizrahi
Modified: 2018-03-27 00:22 UTC (History)
30 users (show)

Fixed In Version: qemu-kvm-rhev-2.9.0-1.el7
Doc Type: Enhancement
Doc Text:
Clone Of:
: 760547 (view as bug list)
Environment:
Last Closed: 2017-08-01 23:27:12 UTC
Target Upstream Version:
Embargoed:

Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2017:2392 0 normal SHIPPED_LIVE Important: qemu-kvm-rhev security, bug fix, and enhancement update 2017-08-01 20:04:36 UTC

Description Saggi Mizrahi 2011-11-02 12:03:38 UTC 
Description of problem:
I would like to be able to tell qemu the exact chain of images and let it override the information written within the image metadata

The arg should be something on the line of:
-drive=qcow2:/tmp/A.img,qcow2:/tmp/B.img,raw:/tmp/c.img

The exact formatting is unimportant as long as separators can be escaped and image format can also be specified.

This will allow users that have the base image in multiple location specify the base image on-the-fly without changing the image metadata.

Version-Release number of selected component (if applicable):


How reproducible:


Steps to Reproduce:
1.
2.
3.
  
Actual results:


Expected results:


Additional info:
Comment 2 Dor Laor 2011-11-02 12:38:02 UTC 
Why not use qemu-img to change the meta data?
Orit, maybe we'll need it for iscsi+block live migration anyway
Comment 3 Kevin Wolf 2011-11-02 13:17:53 UTC 
This is another instance of these "we need -blockdev" features. Reassigning to Markus. If there is no RFE for it yet, we can take this one, otherwise this should probably be closed as a duplicate.
Comment 4 Saggi Mizrahi 2011-11-02 13:38:25 UTC 
Changing the MD is costly and requires write privileged to all the files in the chain.

Also on long chains we might want to have different chains on different hosts (Locally cached templates). This will mean changing the Metadata while a VM is running. And will mean exclusively locking the template because the same VM might want to be used by another VM on another host.

The point is we have to assume base images never change. This changing the metadata before each VM run breaks this assumption.
Comment 5 Orit Wasserman 2011-11-03 12:21:13 UTC 
(In reply to comment #2)
> Why not use qemu-img to change the meta data?
> Orit, maybe we'll need it for iscsi+block live migration anyway
Dor,We don't need to modify the meta data in iscsi+block live migration.
Comment 7 Markus Armbruster 2011-12-02 15:23:59 UTC 
I think this is a fair RFE.  It needs to be pursued upstream.  No ETA, yet.
Comment 17 Saggi Mizrahi 2012-07-05 20:50:10 UTC 
I would just like to clarify that the qemu-img tool also needs a way to have the entire chain passed to it.
Comment 26 Kevin Wolf 2014-07-15 13:53:48 UTC 
Basic support is already in 7.0, however even upstream there are a few parts
missing:

* Support for network protocol drivers in blockdev-add
* Modifying backing file options doesn't work for all options yet (e.g. cache)

We're relatively close to implementing these, so I'll leave this BZ for 7.1
for the moment, while keeping cond-nack upstream.
Comment 27 Markus Armbruster 2014-07-16 14:36:48 UTC 
Also missing upstream: blockdev-del.  Tracked for 7.1 as bug 1086193.
Comment 28 Kevin Wolf 2014-10-22 09:40:25 UTC 
Making progress upstream, but the full implementation won't make it for 7.1.
Comment 30 Ademar Reis 2016-03-15 17:04:12 UTC 
blockdev-add/del is still experimental upstream. We don't expect it to be declared stable (API wise) on time for RHEL-7.3, so deferring it to 7.4.
Comment 34 CongLi 2017-05-05 03:32:01 UTC 
Based on
1. Bug 1086193 - RFE: Add blockdev-delete QMP command in company with blockdev-add - VERIFIED
https://bugzilla.redhat.com/show_bug.cgi?id=1086193#c16

2. Bug 1159728 - add blockdev-add support with libiscsi backends - VERIFIED
https://bugzilla.redhat.com/show_bug.cgi?id=1159728#c7

3. Bug 1159726 - RFE: blockdev-add support for gluster - VERIFIED
https://bugzilla.redhat.com/show_bug.cgi?id=1159726#c8


Set bug status to 'VERIFIED'.

Thanks.
Comment 36 errata-xmlrpc 2017-08-01 23:27:12 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.

https://access.redhat.com/errata/RHSA-2017:2392
Comment 37 errata-xmlrpc 2017-08-02 01:04:50 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.

https://access.redhat.com/errata/RHSA-2017:2392
Comment 38 errata-xmlrpc 2017-08-02 01:56:50 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.

https://access.redhat.com/errata/RHSA-2017:2392
Comment 39 errata-xmlrpc 2017-08-02 02:37:35 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.

https://access.redhat.com/errata/RHSA-2017:2392
Comment 40 errata-xmlrpc 2017-08-02 03:02:18 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.

https://access.redhat.com/errata/RHSA-2017:2392
Comment 41 errata-xmlrpc 2017-08-02 03:22:27 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.

https://access.redhat.com/errata/RHSA-2017:2392
Note You need to log in before you can comment on or make changes to this bug.