Is it a known issue?
Below is the traceback:

07:52:14 ======================================================================
07:52:14 ERROR: test_add_ipv6_gateway_given_existing_ipv4_and_ipv6_gateways (network.ip_address_test.TestAddressSetup)
07:52:14 ----------------------------------------------------------------------
07:52:14 Traceback (most recent call last):
07:52:14   File "/home/jenkins/workspace/vdsm_master_check-patch-fc27-x86_64/vdsm/tests/network/ip_address_test.py", line 146, in test_add_ipv6_gateway_given_existing_ipv4_and_ipv6_gateways
07:52:14     address.add(nic, ipv4=None, ipv6=ipv6)
07:52:14   File "/home/jenkins/workspace/vdsm_master_check-patch-fc27-x86_64/vdsm/lib/vdsm/network/ip/address/__init__.py", line 278, in add
07:52:14     _add_ipv6_address(iface, ipv6)
07:52:14   File "/home/jenkins/workspace/vdsm_master_check-patch-fc27-x86_64/vdsm/lib/vdsm/network/ip/address/__init__.py", line 294, in _add_ipv6_address
07:52:14     ipwrapper.addrAdd(iface, ipv6addr, ipv6netmask, family=6)
07:52:14   File "/home/jenkins/workspace/vdsm_master_check-patch-fc27-x86_64/vdsm/lib/vdsm/network/ipwrapper.py", line 574, in addrAdd
07:52:14     _exec_cmd(command)
07:52:14   File "/home/jenkins/workspace/vdsm_master_check-patch-fc27-x86_64/vdsm/lib/vdsm/network/ipwrapper.py", line 495, in _exec_cmd
07:52:14     raise exc(returnCode, error.splitlines())
07:52:14 vdsm.network.ipwrapper.IPRoute2Error: (2, ['RTNETLINK answers: Permission denied'])

Link to CI console: https://jenkins.ovirt.org/job/vdsm_master_check-patch-fc27-x86_64/3750/consoleFull