Description of problem:
When attempting to install Ovirt hosted engine on CentOS 8.2 the setup fails when creating ovirtmgmt bridge with the following error message:

[ ERROR ] fatal: [localhost]: FAILED! => {"changed": false, "msg": "The host has been set in non_operational status, deployment errors:   code 505: Host h1-mgmt.limetransit.com installation failed. Failed to configure management network on the host.,    code 1120: Failed to configure management network on host h1-mgmt.limetransit.com due to setup networks failure., code 9000: Failed to verify Power Management configuration for Host h1-mgmt.limetransit.com.,    code 10802: VDSM h1-mgmt.limetransit.com command HostSetupNetworksVDS failed: Internal JSON-RPC error: {'reason': 'Unexpected failure of libnm when running the mainloop: run execution'},   fix accordingly and re-deploy."}

The network setup is a physical interface enp4s0 which receives external traffic untagged. On the same port there is a vlan interface, which should be used as the management network and hence on which the ovirtmgmt bridge should be created.

[root@h1-mgmt ~]# nmcli con show
NAME         UUID                                  TYPE      DEVICE
enp4s0       af7ccb53-011b-4c36-998a-1878b4ae7100  ethernet  enp4s0
enp4s0.4000  ecc8064d-18c1-99b7-3fe4-9c5a593ece6f  vlan      enp4s0.4000
[root@h1-mgmt ~]# nmstatectl show
---
dns-resolver:
  config:
    search: []
    server:
    - 213.133.98.98
  running:
    search: []
    server:
    - 213.133.98.98
route-rules:
  config: []
routes:
  config:
  - destination: 0.0.0.0/0
    metric: -1
    next-hop-address: 144.76.84.65
    next-hop-interface: enp4s0
    table-id: 0
  - destination: ::/0
    metric: -1
    next-hop-address: fe80::1
    next-hop-interface: enp4s0
    table-id: 0
  running:
  - destination: 0.0.0.0/0
    metric: 100
    next-hop-address: 144.76.84.65
    next-hop-interface: enp4s0
    table-id: 254
  - destination: 144.76.84.65/32
    metric: 100
    next-hop-address: ''
    next-hop-interface: enp4s0
    table-id: 254
  - destination: 172.27.1.0/24
    metric: 400
    next-hop-address: ''
    next-hop-interface: enp4s0.4000
    table-id: 254
  - destination: 2a01:4f8:192:1148::/64
    metric: 100
    next-hop-address: ''
    next-hop-interface: enp4s0
    table-id: 254
  - destination: ::/0
    metric: 100
    next-hop-address: fe80::1
    next-hop-interface: enp4s0
    table-id: 254
  - destination: fe80::/64
    metric: 100
    next-hop-address: ''
    next-hop-interface: enp4s0
    table-id: 254
  - destination: ff00::/8
    metric: 256
    next-hop-address: ''
    next-hop-interface: enp4s0
    table-id: 255
interfaces:
- name: ;vdsmdummy;
  type: linux-bridge
  state: down
  ipv4:
    enabled: false
  ipv6:
    enabled: false
  mac-address: B2:9E:E0:61:71:88
  mtu: 1500
- name: br-int
  type: unknown
  state: down
  ipv4:
    enabled: false
  ipv6:
    enabled: false
  mac-address: 6E:37:94:63:E0:4B
  mtu: 1500
- name: enp4s0
  type: ethernet
  state: up
  ethernet:
    auto-negotiation: true
    duplex: full
    speed: 1000
  ipv4:
    address:
    - ip: 144.76.84.73
      prefix-length: 32
    dhcp: false
    enabled: true
  ipv6:
    address:
    - ip: 2a01:4f8:192:1148::2
      prefix-length: 64
    - ip: fe80::62a4:4cff:fee9:4ac
      prefix-length: 64
    auto-dns: true
    auto-gateway: true
    auto-routes: true
    autoconf: true
    dhcp: true
    enabled: true
  mac-address: 60:A4:4C:E9:04:AC
  mtu: 1500
- name: enp4s0.4000
  type: vlan
  state: up
  ipv4:
    address:
    - ip: 172.27.1.1
      prefix-length: 24
    dhcp: false
    enabled: true
  ipv6:
    autoconf: false
    dhcp: false
    enabled: false
  mac-address: 60:A4:4C:E9:04:AC
  mtu: 1500
  vlan:
    base-iface: enp4s0
    id: 4000
- name: lo
  type: unknown
  state: down
  ipv4:
    enabled: false
  ipv6:
    enabled: false
  mtu: 65536
- name: ovs-system
  type: unknown
  state: down
  ipv4:
    enabled: false
  ipv6:
    enabled: false
  mac-address: A2:35:7A:6C:B7:EF
  mtu: 1500

It appears vdsm attempts to create a network setup where enp4s0 does not have any address, but that fails because it has a ipv6 route. This is the output in vdsm log:

MainProcess|jsonrpc/0::DEBUG::2020-09-02 16:38:25,897::supervdsm_server::93::SuperVdsm.ServerCallback::(wrapper) call setupNetworks with ({'ovirtmgmt': {'vlan': '4000', 'netmask': '255.255.255.0', 'ipv6autoconf': False,
'nic': 'enp4s0', 'bridged': 'true', 'ipaddr': '172.27.1.1', 'defaultRoute': True, 'dhcpv6': False, 'STP': 'no', 'mtu': 1500, 'switch': 'legacy'}}, {}, {'connectivityTimeout': 120, 'commitOnSuccess': True, 'connectivityCh
eck': 'true'}) {}
MainProcess|jsonrpc/0::INFO::2020-09-02 16:38:25,897::api::220::root::(setupNetworks) Setting up network according to configuration: networks:{'ovirtmgmt': {'vlan': '4000', 'netmask': '255.255.255.0', 'ipv6autoconf': Fal
se, 'nic': 'enp4s0', 'bridged': 'true', 'ipaddr': '172.27.1.1', 'defaultRoute': True, 'dhcpv6': False, 'STP': 'no', 'mtu': 1500, 'switch': 'legacy'}}, bondings:{}, options:{'connectivityTimeout': 120, 'commitOnSuccess':
True, 'connectivityCheck': 'true'}
MainProcess|jsonrpc/0::DEBUG::2020-09-02 16:38:25,902::cmdutils::130::root::(exec_cmd) /sbin/tc qdisc show (cwd None)
MainProcess|jsonrpc/0::DEBUG::2020-09-02 16:38:25,906::cmdutils::138::root::(exec_cmd) SUCCESS: <err> = b''; <rc> = 0
MainProcess|jsonrpc/0::DEBUG::2020-09-02 16:38:25,945::vsctl::74::root::(commit) Executing commands: /usr/bin/ovs-vsctl --timeout=5 --oneline --format=json -- list Bridge -- list Port -- list Interface
MainProcess|jsonrpc/0::DEBUG::2020-09-02 16:38:25,945::cmdutils::130::root::(exec_cmd) /usr/bin/ovs-vsctl --timeout=5 --oneline --format=json -- list Bridge -- list Port -- list Interface (cwd None)
MainProcess|jsonrpc/0::DEBUG::2020-09-02 16:38:25,952::cmdutils::138::root::(exec_cmd) SUCCESS: <err> = b''; <rc> = 0
MainProcess|jsonrpc/0::INFO::2020-09-02 16:38:25,957::netconfpersistence::58::root::(setNetwork) Adding network ovirtmgmt({'vlan': 4000, 'netmask': '255.255.255.0', 'ipv6autoconf': False, 'nic': 'enp4s0', 'bridged': True
, 'ipaddr': '172.27.1.1', 'defaultRoute': True, 'dhcpv6': False, 'mtu': 1500, 'switch': 'legacy', 'stp': False, 'bootproto': 'none', 'nameservers': ['213.133.98.98']})
MainProcess|jsonrpc/0::DEBUG::2020-09-02 16:38:25,958::commands::153::common.commands::(start) /usr/bin/taskset --cpu-list 0-7 /usr/libexec/vdsm/hooks/before_network_setup/50_fcoe (cwd None)
MainProcess|jsonrpc/0::INFO::2020-09-02 16:38:26,154::hooks::122::root::(_runHooksDir) /usr/libexec/vdsm/hooks/before_network_setup/50_fcoe: rc=0 err=b''
MainProcess|jsonrpc/0::INFO::2020-09-02 16:38:26,155::configurator::195::root::(_setup_nmstate) Processing setup through nmstate
MainProcess|jsonrpc/0::INFO::2020-09-02 16:38:26,175::configurator::197::root::(_setup_nmstate) Desired state: {'interfaces': [{'name': 'enp4s0', 'state': 'up', 'mtu': 1500}, {'vlan': {'id': 4000, 'base-iface': 'enp4s0'}
, 'name': 'enp4s0.4000', 'type': 'vlan', 'state': 'up', 'mtu': 1500, 'ipv4': {'enabled': False}, 'ipv6': {'enabled': False}}, {'name': 'ovirtmgmt', 'type': 'linux-bridge', 'state': 'up', 'mtu': 1500, 'bridge': {'port': [
{'name': 'enp4s0.4000'}], 'options': {'stp': {'enabled': False}}}, 'ipv4': {'enabled': True, 'address': [{'ip': '172.27.1.1', 'prefix-length': 24}], 'dhcp': False}, 'ipv6': {'enabled': False}}], 'dns-resolver': {'config'
: {'server': ['213.133.98.98']}}}
MainProcess|jsonrpc/0::DEBUG::2020-09-02 16:38:26,217::checkpoint::121::root::(create) Checkpoint /org/freedesktop/NetworkManager/Checkpoint/1 created for all devices: 60
MainProcess|jsonrpc/0::DEBUG::2020-09-02 16:38:26,218::netapplier::239::root::(_add_interfaces) Adding new interfaces: ['ovirtmgmt']
MainProcess|jsonrpc/0::DEBUG::2020-09-02 16:38:26,221::netapplier::251::root::(_edit_interfaces) Editing interfaces: ['enp4s0.4000', 'enp4s0']
MainProcess|jsonrpc/0::DEBUG::2020-09-02 16:38:26,224::nmclient::136::root::(execute_next_action) Executing NM action: func=add_connection_async
MainProcess|jsonrpc/0::DEBUG::2020-09-02 16:38:26,231::connection::329::root::(_add_connection_callback) Connection adding succeeded: dev=ovirtmgmt
MainProcess|jsonrpc/0::DEBUG::2020-09-02 16:38:26,232::nmclient::136::root::(execute_next_action) Executing NM action: func=commit_changes_async
MainProcess|jsonrpc/0::ERROR::2020-09-02 16:38:26,233::nmclient::200::root::(quit) NM main-loop aborted: Connection update failed: error=nm-connection-error-quark: ipv6.gateway: gateway cannot be set if there are no addresses configured (7), dev=enp4s0/<enum NM_DEVICE_STATE_ACTIVATED of type NM.DeviceState>
MainProcess|jsonrpc/0::DEBUG::2020-09-02 16:38:26,246::checkpoint::164::root::(rollback) Checkpoint /org/freedesktop/NetworkManager/Checkpoint/1 rollback executed: dbus.Dictionary({dbus.String('/org/freedesktop/NetworkManager/Devices/6'): dbus.UInt32(0), dbus.String('/org/freedesktop/NetworkManager/Devices/7'): dbus.UInt32(0), dbus.String('/org/freedesktop/NetworkManager/Devices/8'): dbus.UInt32(0), dbus.String('/org/freedesktop/NetworkManager/Devices/9'): dbus.UInt32(0), dbus.String('/org/freedesktop/NetworkManager/Devices/3'): dbus.UInt32(0), dbus.String('/org/freedesktop/NetworkManager/Devices/2'): dbus.UInt32(0), dbus.String('/org/freedesktop/NetworkManager/Devices/4'): dbus.UInt32(0), dbus.String('/org/freedesktop/NetworkManager/Devices/1'): dbus.UInt32(0), dbus.String('/org/freedesktop/NetworkManager/Devices/5'): dbus.UInt32(0)}, signature=dbus.Signature('su'))
MainProcess|jsonrpc/0::ERROR::2020-09-02 16:38:31,251::supervdsm_server::97::SuperVdsm.ServerCallback::(wrapper) Error in setupNetworks
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/network/api.py", line 241, in setupNetworks
    _setup_networks(networks, bondings, options, net_info)
  File "/usr/lib/python3.6/site-packages/vdsm/network/api.py", line 266, in _setup_networks
    networks, bondings, options, net_info, in_rollback
  File "/usr/lib/python3.6/site-packages/vdsm/network/netswitch/configurator.py", line 154, in setup
    _setup_nmstate(networks, bondings, options, in_rollback)
  File "/usr/lib/python3.6/site-packages/vdsm/network/netswitch/configurator.py", line 199, in _setup_nmstate
    nmstate.setup(desired_state, verify_change=not in_rollback)
  File "/usr/lib/python3.6/site-packages/vdsm/network/nmstate.py", line 63, in setup
    state_apply(desired_state, verify_change=verify_change)
  File "/usr/lib/python3.6/site-packages/libnmstate/deprecation.py", line 40, in wrapper
    return func(*args, **kwargs)
  File "/usr/lib/python3.6/site-packages/libnmstate/nm/nmclient.py", line 96, in wrapped
    ret = func(*args, **kwargs)
  File "/usr/lib/python3.6/site-packages/libnmstate/netapplier.py", line 73, in apply
    state.State(desired_state), verify_change, commit, rollback_timeout
  File "/usr/lib/python3.6/site-packages/libnmstate/netapplier.py", line 163, in _apply_ifaces_state
    con_profiles=ifaces_add_configs + ifaces_edit_configs,
  File "/usr/lib64/python3.6/contextlib.py", line 88, in __exit__
    next(self.gen)
  File "/usr/lib/python3.6/site-packages/libnmstate/netapplier.py", line 232, in _setup_providers
    mainloop.run(timeout=MAINLOOP_TIMEOUT)
  File "/usr/lib/python3.6/site-packages/libnmstate/nm/nmclient.py", line 177, in run
    f"Unexpected failure of libnm when running the mainloop: {err}"
libnmstate.error.NmstateLibnmError: Unexpected failure of libnm when running the mainloop: run execution

Version-Release number of selected component (if applicable):
[root@h1-mgmt vdsm]# rpm -q vdsm
vdsm-4.40.22-1.el8.x86_64

How reproducible:
Create a physical network interface with a vlan interface, both having ip addresses. Select the vlan interface as bridge interface. 

Steps to Reproduce:
1.
2.
3.

Actual results:
If the physical interface have an ipv6 route it will fail as above, if it only have ipv4 address then probably enp4s0 will be without ip address.

Expected results:
enp4s0 will keep it's addresses and vlan interface enp4s0.4000 will be bridged with ovirtmgmt.

Additional info: