Simple patch posted:
https://www.redhat.com/archives/libguestfs/2018-July/msg00035.html

Fixed upstream with
https://github.com/libguestfs/libguestfs/commit/682d3f8b01bcf8260b4ddeb7e4bc7ea276f38f35
which is in libguestfs >= 1.39.8.

Verify the bug with builds:
virt-v2v-1.38.2-9.el7.x86_64
libguestfs-1.38.2-9.el7.x86_64
nbdkit-plugin-python2-1.2.4-4.el7.x86_64
nbdkit-1.2.4-4.el7.x86_64
nbdkit-plugin-python-common-1.2.4-4.el7.x86_64


Steps:
1.Try to convert guest to rhv4.2 using rhv-upload without installing python-ovirt-engine-sdk4 package

1.1 # rpm -qa |grep ovirt-engine
noting

1.2 # virt-v2v -ic vpx://vsphere.local%5cAdministrator.73.141/data/10.73.75.219/?no_verify=1  esx6.7-rhel7.5-x86_64 -o rhv-upload -oc https://ibm-x3250m5-03.rhts.eng.pek2.redhat.com/ovirt-engine/api -os nfs_data -op /tmp/rhvpasswd -oo rhv-cafile=/home/ca.pem  -oo rhv-direct=true -of raw --password-file /tmp/passwd
Traceback (most recent call last):
  File "<string>", line 1, in <module>
ImportError: No module named ovirtsdk4
virt-v2v: error: the Python module ‘ovirtsdk4’ could not be loaded, is 
it installed?  See previous messages for problems.

If reporting bugs, run virt-v2v with debugging enabled and include the 
complete output:

  virt-v2v -v -x [...]


Hi Pino,

   Could make package name "python-ovirt-engine-sdk4" showing in the error message?

(In reply to mxie from comment #5)
>    Could make package name "python-ovirt-engine-sdk4" showing in the error
> message?

I could, however:
- it would be a downstream-only change
- mentioning the package name alone will not be helpful either, since you need anyway to add extra channels to get it
- rhv-upload is mainly driven by CFME, and already dependencies will be taken care prior of calling virt-v2v
- users using rhv-upload manually need already to do extra steps

Because of the reasons above, IMHO the best action is to just document the manual procedure in KB (Knowledge Base), so the proper channels & package names can be be described in detail (which you cannot do in a simple error message).

(In reply to Pino Toscano from comment #6)
> (In reply to mxie from comment #5)
> >    Could make package name "python-ovirt-engine-sdk4" showing in the error
> > message?
> 
> I could, however:
> - it would be a downstream-only change
> - mentioning the package name alone will not be helpful either, since you
> need anyway to add extra channels to get it
> - rhv-upload is mainly driven by CFME, and already dependencies will be
> taken care prior of calling virt-v2v
> - users using rhv-upload manually need already to do extra steps
> 
> Because of the reasons above, IMHO the best action is to just document the
> manual procedure in KB (Knowledge Base), so the proper channels & package
> names can be be described in detail (which you cannot do in a simple error
> message).

Thanks for your reply,creating KB to record the proper channels & package is really good idea, but who will write this Knowledge Base? Do I need to track this in bug? Can I move the bug to verified firstly?

(In reply to mxie from comment #7)
> Thanks for your reply,creating KB to record the proper channels & package is
> really good idea, but who will write this Knowledge Base?

I'm in touch already with the documentation team, this is definitely under my radar.

> Can I move the bug to verified firstly?

I'd say so, yes.

Thanks!

Thanks Pino, according to comment5 ~ comment8, move the bug from ON_QA to VERIFIED

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-2018:3021