Bug 1667037

Description of problem:

We are unable to migrate virtual machines running on a cephfs (posix) storage domain.

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

libvirt-4.5.0-10.el7_6.3.x86_64

How reproducible:

always

Steps to Reproduce:
1. create virtual machine on cephfs (posix) storage domain
2. try to migrate the virtual machine

Actual results:

migration of virtual machine is not successful

Expected results:

virtual machine migration without problems

Additional info:

seems to be related to:
https://bugzilla.redhat.com/show_bug.cgi?id=1640465
https://bugzilla.redhat.com/show_bug.cgi?id=1632711

We get following libvirt error:

2019-01-16 17:52:22,187+0100 ERROR (migsrc/b5a6fc67) [virt.vm] (vmId='b5a6fc67-1cd3-4fa6-8ecc-304494164a4a') Failed to migrate (migration:455)
Traceback (most recent call last):
  File "/usr/lib/python2.7/site-packages/vdsm/virt/migration.py", line 437, in _regular_run
    self._startUnderlyingMigration(time.time())
  File "/usr/lib/python2.7/site-packages/vdsm/virt/migration.py", line 509, in _startUnderlyingMigration
    self._perform_with_conv_schedule(duri, muri)
  File "/usr/lib/python2.7/site-packages/vdsm/virt/migration.py", line 587, in _perform_with_conv_schedule
    self._perform_migration(duri, muri)
  File "/usr/lib/python2.7/site-packages/vdsm/virt/migration.py", line 529, in _perform_migration
    self._migration_flags)
  File "/usr/lib/python2.7/site-packages/vdsm/virt/virdomain.py", line 98, in f
    ret = attr(*args, **kwargs)
  File "/usr/lib/python2.7/site-packages/vdsm/common/libvirtconnection.py", line 130, in wrapper
    ret = f(*args, **kwargs)
  File "/usr/lib/python2.7/site-packages/vdsm/common/function.py", line 92, in wrapper
    return func(inst, *args, **kwargs)
  File "/usr/lib64/python2.7/site-packages/libvirt.py", line 1779, in migrateToURI3
    if ret == -1: raise libvirtError ('virDomainMigrateToURI3() failed', dom=self)
libvirtError: Unsafe migration: Migration without shared storage is unsafe