+++ This bug was initially created as a clone of Bug #1842767 +++

Description of problem:
volumeEmptyCheck in vdsm-gluster doesn't work and throws error.


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


How reproducible:


Steps to Reproduce:
1.Setup a ovirt-gluster hci cluster
2.Run vdsm-client --gluster-enabled GlusterVolume volumeEmptyCheck volumeName=data on one of the hosts.

Actual results:
Volume empty check is issued by vdsm-client.
Errors:
vdsm-client: Command GlusterVolume.volumeEmptyCheck with args {'volumeName': 'data'} failed:
(code=4574, message=Failed to Check if gluster volume is empty: rc=1 out=[b'/usr/bin/python3: No module named gluster.gfapi\n'] err=())

Expected results:
No errors should be observed.

Additional info:
Similar to a other functionalities in gfapi.py which throws error and needs rework.

excerpt from supervdsm log
MainProcess|jsonrpc/7::ERROR::2020-06-02 10:28:52,973::supervdsm_server::97::SuperVdsm.ServerCallback::(wrapper) Error in volumeEmptyCheck
Traceback (most recent call last):
  File "/usr/lib/python3.6/site-packages/vdsm/gluster/gfapi.py", line 266, in volumeEmptyCheck
    out = commands.run(command, env=env)
  File "/usr/lib/python3.6/site-packages/vdsm/common/commands.py", line 101, in run
    raise cmdutils.Error(args, p.returncode, out, err)
vdsm.common.cmdutils.Error: Command ['/usr/bin/python3', '-m', 'gluster.gfapi', '-v', 'data', '-p', '24007', '-H', 'localhost', '-t', 'tcp', '-c', 'readdir'] failed with rc=1 out=b'' err=b'/usr/bin/python3: No module named gluster.gfapi\n'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/lib/python3.6/site-packages/vdsm/supervdsm_server.py", line 95, in wrapper
    res = func(*args, **kwargs)
  File "/usr/lib/python3.6/site-packages/vdsm/gluster/gfapi.py", line 268, in volumeEmptyCheck
    raise ge.GlusterVolumeEmptyCheckFailedException(e.rc, [e.err])
vdsm.gluster.exception.GlusterVolumeEmptyCheckFailedException: Failed to Check if gluster volume is empty: rc=1 out=[b'/usr/bin/python3: No module named gluster.gfapi\n'] err=()

--- Additional comment from Yaniv Kaul on 2020-06-02 07:59:25 UTC ---

Hmmm, are you running with libgfapi?

--- Additional comment from Kaustav Majumder on 2020-06-02 09:36:34 UTC ---

(In reply to Yaniv Kaul from comment #1)
> Hmmm, are you running with libgfapi?

With and without, have checked. Both giving the same errors.

--- Additional comment from Sahina Bose on 2020-06-03 12:58:30 UTC ---

(In reply to Yaniv Kaul from comment #1)
> Hmmm, are you running with libgfapi?

gfapi is also used in vdsm to check volume size - this has no relation to the gfapi driver in qemu. The failure seen here is from the internal usage of gfapi to query volume size.