Bug 1477880

Summary:	can't use default LUN of iscsi protocol used in network type virtual disk when don't specify the LUN
Product:	Red Hat Enterprise Linux 7	Reporter:	Meina Li <meili>
Component:	libvirt	Assignee:	John Ferlan <jferlan>
Status:	CLOSED ERRATA	QA Contact:	Meina Li <meili>
Severity:	medium	Docs Contact:
Priority:	unspecified
Version:	7.4	CC:	dyuan, lmen, rbalakri, xuzhang, yisun
Target Milestone:	rc
Target Release:	---
Hardware:	x86_64
OS:	Linux
Whiteboard:
Fixed In Version:	libvirt-3.8.0-1.el7	Doc Type:	No Doc Update
Doc Text:	undefined	Story Points:	---
Clone Of:		Environment:
Last Closed:	2018-04-10 10:52:40 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 Meina Li 2017-08-03 06:53:34 UTC

Description of problem:
can't use default LUN of iscsi protocol used in network type virtual disk when don't specify the LUN, which don't match our documentation that indicate "The above page indicate some points:For "iscsi" (since 1.0.4), the name attribute may include a logical unit number, separated from the target's name by a slash (e.g.,iqn.2013-07.com.example:iscsi-pool/1). If not specified, the default LUN is zero" in http://libvirt.org/formatdomain.html#elementsDisks.

Version-Release number of selected component (if applicable):
libvirt-3.2.0-14.virtcov.el7_4.2.x86_64
kernel-3.10.0-693.el7.x86_64
qemu-kvm-rhev-2.9.0-16.el7_4.3.x86_64

How reproducible:
100%

Steps to Reproduce:
1. On the iscsi-initiator machine, define and start a guest.

2.Attach a iscsi network disk with xml below:
#more iscsi.xml
<disk type='network' device='disk'>
<driver name="qemu" type="raw"/>
<source protocol="iscsi" name="iqn.2013-10.com.example:iscsi/0">
<host name="10.66.4.164" port="3260"/>
</source>
<target dev="vdb" bus="virtio"/>
</disk>
# virsh attach-device r7-qcow2 iscsi.xml
Device attached successfully
# virsh detach-device r7-qcow2 iscsi.xml
Device detached successfull

3.Modify iscsi.xml and ttach a iscsi network disk with xml below:
#more iscsi.xml
<disk type='network' device='disk'>
<driver name="qemu" type="raw"/>
<source protocol="iscsi" name="iqn.2013-10.com.example:iscsi">
<host name="10.66.4.164" port="3260"/>
</source>
<target dev="vdb" bus="virtio"/>
</disk>
# virsh attach-device r7-qcow2 iscsi.xml
error: Failed to attach device from iscsi.xml
error: internal error: unable to execute QEMU command '__com.redhat_drive_add': Device 'drive-virtio-disk1' could not be initialized

Actual results:
step3:
# virsh attach-device r7-qcow2 iscsi.xml
error: Failed to attach device from iscsi.xml
error: internal error: unable to execute QEMU command '__com.redhat_drive_add': Device 'drive-virtio-disk1' could not be initialized

Expected results:
step3:
# virsh attach-device r7-qcow2 iscsi.xml
Device attached successfully

Additional info:
http://libvirt.org/formatdomain.html#elementsDisks: For "iscsi" (since 1.0.4), the name attribute may include a logical unit number, separated from the target's name by a slash (e.g.,iqn.2013-07.com.example:iscsi-pool/1). If not specified, the default LUN is zero

Comment 2 yisun 2017-08-04 03:25:38 UTC

not related to npiv, remove it from white board key word

Comment 3 John Ferlan 2017-09-06 16:09:39 UTC

Strange this was never checked before - sometimes the power of the documentation does make believers.  In any case, posted the following patch upstream to resolve:

https://www.redhat.com/archives/libvir-list/2017-September/msg00122.html

Comment 4 John Ferlan 2017-09-11 23:28:05 UTC

First patch had negative review, so v2 was generated:

https://www.redhat.com/archives/libvir-list/2017-September/msg00248.html

Primary difference is the XML is adjusted during post parse processing rather than during command creation. This results in a change to the output XML as well.

Since QEMU didn't really support a non-supplied value, this should be fine.

Comment 5 John Ferlan 2017-09-12 14:50:36 UTC

Patch has been pushed:

commit f64f03b5b1e6f3ecd6c6d79316c3efedc00c2167
Author: John Ferlan <jferlan>
Date:   Mon Sep 11 19:18:21 2017 -0400

    qemu: Provide default LUN=0 for iSCSI if not provided
    
...
    
    If the "/#" is missing from the provided iSCSI path, then we need
    to provide the default LUN of /0; otherwise, QEMU will fail to parse
    the URL causing a failure to either create the guest or hotplug
    attach the storage.
    
    During post parse, for any iSCSI disk or hostdev, scan the source
    path looking for the presence of '/', if found, then we can assume
    the LUN is provided.  If not found, alter the input XML to add the
    "/0".  This will cause the generated XML to have the generated
    value when the domain config is saved after post parse.

$ git describe f64f03b5b1e6f3ecd6c6d79316c3efedc00c2167
v3.7.0-52-gf64f03b5b
$

Comment 7 Meina Li 2017-10-20 10:33:09 UTC

Test env components:
kernel-3.10.0-734.el7.x86_64
libvirt-3.8.0-1.el7.x86_64
qemu-kvm-rhev-2.10.0-2.el7.x86_64

Steps to verify:
Scenario 1:
1. iSCSI network disk XML(network-disk.xml):
 <disk type='network' device='disk'>
      <driver name='qemu' type='raw'/>
      <source protocol='iscsi' name='iqn.2003-01.org.linux-iscsi.hostname.x8664:sn.target1'>
        <host name='10.73.224.151' port='3260'/>
      </source>
      <target dev='vdb' bus='virtio'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x0b' function='0x0'/>
  </disk>

2. Attach/detach the disk and check the status:
# virsh attach-device lmn network-disk.xml 
Device attached successfully

# virsh domblklist lmn
Target     Source
------------------------------------------------
vda        /var/lib/libvirt/images/lmn.qcow2
vdb        iqn.2003-01.org.linux-iscsi.hostname.x8664:sn.target1/0

# virsh detach-device lmn network-disk.xml 
Device detached successfully

Scenario 2:
1. iSCSI network lun XML(network-lun.xml):
 <disk type='network' device='lun'>
      <driver name='qemu' type='raw'/>
      <source protocol='iscsi' name='iqn.2003-01.org.linux-iscsi.hostname.x8664:sn.target1'>
        <host name='10.73.224.151' port='3260'/>
      </source>
      <target dev='sdb' bus='scsi'/>
      <address type='drive' controller='0' bus='0' target='0' unit='1'/>
    </disk>

2. Attach/detach the disk and check the status:
# virsh attach-device lmn network-lun.xml 
Device attached successfully

# virsh domblklist lmn
Target     Source
------------------------------------------------
vda        /var/lib/libvirt/images/lmn.qcow2
sdb        iqn.2003-01.org.linux-iscsi.hostname.x8664:sn.target1/0

# virsh detach-device lmn network-lun.xml 
Device detached successfully


Scenario 3:
1. iSCSI hostdev with no scsi controller model:
1)Domain's scsi controller in XML:
<controller type='scsi' index='0'>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
</controller>
2)iSCSI hostdev XML(hostdev-lsi.xml)
<hostdev mode='subsystem' type='scsi' managed='yes'>
      <source protocol='iscsi' name='iqn.2003-01.org.linux-iscsi.hostname.x8664:sn.target1'>
        <host name='10.73.224.151' port='3260'/>
      </source>
      <alias name='hostdev0'/>
      <address type='drive' controller='0' bus='0' target='0' unit='4'/>
    </hostdev>

2. Attach/ the host device and use 'fdisk -l' to check the device in guest:
# virsh attach-device lmn hostdev-lsi.xml 
Device attached successfully

# virsh detach-device lmn hostdev-lsi.xml 
Device detached successfully

Scenario 4:
1. iSCSI hostdev with scsi controller model='virtio-scsi':
1)Domain's scsi controller in XML:
<controller type='scsi' index='0' model='virtio-scsi'>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
</controller>
2)iSCSI hostdev XML(hostdev-virtio.xml)
<hostdev mode='subsystem' type='scsi' managed='yes'>
      <source protocol='iscsi' name='iqn.2003-01.org.linux-iscsi.hostname.x8664:sn.target1'>
        <host name='10.73.224.151' port='3260'/>
      </source>
      <alias name='hostdev0'/>
      <address type='drive' controller='0' bus='0' target='0' unit='4'/>
    </hostdev>

2. Attach the host device and use 'fdisk -l' to check the device in guest:
# virsh attach-device lmn hostdev-virtio.xml 
Device attached successfully

# virsh detach-device lmn hostdev-virtio.xml 
Device detached successfully

The results are as expected, move this bug to be verified.

Comment 11 errata-xmlrpc 2018-04-10 10:52:40 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/RHEA-2018:0704