Note: This bug is displayed in read-only format because the product is no longer active in Red Hat Bugzilla.
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 1120053

Summary: Option shareable does not take effect after injecting a cdrom to guest by attach-disk
Product: Red Hat Enterprise Linux 7 Reporter: Yang Yang <yanyang>
Component: libvirtAssignee: Peter Krempa <pkrempa>
Status: CLOSED ERRATA QA Contact: Virtualization Bugs <virt-bugs>
Severity: medium Docs Contact:
Priority: medium    
Version: 7.1CC: dyuan, jdenemar, mzhan, pkrempa, rbalakri, xuzhang, yisun
Target Milestone: rc   
Target Release: ---   
Hardware: x86_64   
OS: Linux   
Whiteboard:
Fixed In Version: libvirt-1.3.1-1.el7 Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2016-11-03 18:09:47 UTC Type: Bug
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:

Description Yang Yang 2014-07-16 07:41:33 UTC
Description of problem:
Tried to injecting a cdrom to guest by attach-disk passing option shareable. However, libvirt didnot write the element <shareable/> into guest xml

Version-Release number of selected component (if applicable):
libvirt-1.1.1-29.el7.x86_64

How reproducible:
100%

Steps:
1. Prepare a running guest with the following xml
.................
<disk type='file' device='disk'>
      <driver name='qemu' type='qcow2' cache='none'/>
      <source file='/var/lib/libvirt/images/test2.img'/>
      <target dev='vda' bus='virtio'/>
      <alias name='virtio-disk0'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x06' function='0x0'/>
    </disk>
    <disk type='block' device='cdrom'>
      <driver name='qemu' type='raw'/>
      <target dev='hda' bus='ide'/>
      <readonly/>
    </disk>
.................
2. Connect a device to cdrom
# virsh attach-disk test /var/lib/libvirt/images/test.iso hda --type cdrom --shareable
Disk attached successfully

3. check the dumpxml

Expected Results:
In step 3, the element <shareable/> should exist in xml.

<disk type='file' device='cdrom'>
      <driver name='qemu' type='raw'/>
      <source file='/var/lib/libvirt/images/test.iso'/>
      <target dev='hda' bus='ide'/>
      <readonly/>
      <shareable/>
      <alias name='ide0-0-0'/>
      <address type='drive' controller='0' bus='0' target='0' unit='0'/>
    </disk>

Actual Results:
In step 3, the element <shareable/> was not found

<disk type='file' device='cdrom'>
      <driver name='qemu' type='raw'/>
      <source file='/var/lib/libvirt/images/test.iso'/>
      <target dev='hda' bus='ide'/>
      <readonly/>
      <alias name='ide0-0-0'/>
      <address type='drive' controller='0' bus='0' target='0' unit='0'/>
    </disk>


Additional info:

The issue was also hit when injecting a cdrom to guest by attach-disk passing option --mode shareable.
# virsh attach-disk test /var/lib/libvirt/images/test.iso hda --type cdrom --mode shareable

Comment 2 Peter Krempa 2014-08-01 08:36:10 UTC
quick glance at the code reveals that "attach-disk" on an existing cdrom device just updates the media in the drive and cdrom device hotplug isn't supported at all. The problem lies in just changing the media and ignoring the rest of the XML.

Additionally the media change function is flawed as it doesn't handle remote storage.

Comment 6 Peter Krempa 2016-02-11 07:05:43 UTC
This was fixed by:

commit 1f39218e4fdca901f7adca442e6ed6957b6eadef
Author: Peter Krempa <pkrempa>
Date:   Tue Aug 5 13:43:57 2014 +0200

    qemu: hotplug: Change arguments for qemuDomainChangeEjectableMedia
    
    Pass the source of the changed media instead of a complete disk
    definition.
    
    Note that the @disk argument now contains what @olddisk would contain.
    The new source is passed as a virStorageSource struct.

... and possibly few following patches.

v1.2.7-170-g1f39218

Comment 8 yisun 2016-09-02 13:15:21 UTC
Verified on libvirt-2.0.0-6.el7.x86_64 and passed

1. #virsh edit vm
...
    <disk type='block' device='cdrom'>
      <driver name='qemu' type='raw'/>
      <target dev='hda' bus='ide'/>
      <readonly/>
    </disk>
...

2. #virsh start vm
3. #touch /var/lib/libvirt/images/test.iso
4. #virsh attach-disk vm /var/lib/libvirt/images/test.iso hda --type cdrom --shareable

5. # virsh dumpxml vm  | grep disk -A10
...
    <disk type='file' device='cdrom'>
      <driver name='qemu' type='raw'/>
      <source file='/var/lib/libvirt/images/test.iso'/>
      <backingStore/>
      <target dev='hda' bus='ide'/>
      <readonly/>
      <shareable/>   <====== exists
      <alias name='ide0-0-0'/>
      <address type='drive' controller='0' bus='0' target='0' unit='0'/>
    </disk>

6. #virsh destroy vm; virsh start vm
7. # virsh attach-disk vm /var/lib/libvirt/images/test.iso hda --type cdrom --mode shareable

8. # virsh dumpxml vm | grep disk -A10
 ...
    <disk type='file' device='cdrom'>
      <driver name='qemu' type='raw'/>
      <source file='/var/lib/libvirt/images/test.iso'/>
      <backingStore/>
      <target dev='hda' bus='ide'/>
      <readonly/>
      <shareable/>  <====== exists
      <alias name='ide0-0-0'/>
      <address type='drive' controller='0' bus='0' target='0' unit='0'/>
    </disk>

Comment 10 errata-xmlrpc 2016-11-03 18:09:47 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://rhn.redhat.com/errata/RHSA-2016-2577.html