Description of problem:
We installed RHVH on three hosts with four NICs each:
em1: DHCP (gsslab) 10.37.192.0/22
em2: rhvmgmt (tagged VLAN 297) 10.37.198.0/25
em3/4: bonded, gluster (isolated tagged VLAN 302) 192.168.1.0/24
em1 was activated at RHVH install time
rhvmgmt and gluster networks were added after RHVH install e.g.:

nmcli con del em2
nmcli con add type vlan con-name em2.297 ifname em2.297 id 297 dev em2 ip4 10.37.198.1/25

nmcli con del em3 em4
nmcli con add type bond con-name bond0 ifname bond0 mode 4 ipv4.method disabled ipv6.method ignore
nmcli con add type ethernet con-name em3 ifname em3 master bond0
nmcli con add type ethernet con-name em4 ifname em4 master bond0
nmcli con add type vlan con-name bond0.302 ifname bond0.302 dev bond0 id 302 ip4 192.168.1.4/24

We are installing RHHI-V.
We installed gluster with the cockpit wizard.
We then set up RHV on the rhvmgmt network with 'hosted-engine --deploy' (because the wizard failed to complete):

[root@dell-r640-04 ~]# hosted-engine --deploy
          Please indicate a nic to set ovirtmgmt bridge on: (em2.297, em1, bond0.302) [em2.297]:
          Please enter the name of the datacenter where you want to deploy this hosted-engine host. [Default]:
          Please enter the name of the cluster where you want to deploy this hosted-engine host. [Default]:
          If you want to deploy with a custom engine appliance image,
          please specify the path to the OVA archive you would like to use
          (leave it empty to skip, the setup will use rhvm-appliance rpm installing it if missing):
          Engine VM FQDN:  []: rhvm.rhvmgmt.tamlab.brq.redhat.com
          Engine VM domain: [rhvmgmt.tamlab.brq.redhat.com]
          Enter root password that will be used for the engine appliance:
          Confirm appliance root password:
          Enter ssh public key for the root user that will be used for the engine appliance (leave it empty to skip):
          Do you want to enable ssh access for the root user (yes, no, without-password) [yes]:
          Please specify the number of virtual CPUs for the VM (Defaults to appliance OVF value): [4]:
          Please specify the memory size of the VM in MB (Defaults to appliance OVF value): [16384]:
          You may specify a unicast MAC address for the VM or accept a randomly generated default [00:16:3e:07:d7:e8]:
          How should the engine VM network be configured (DHCP, Static)[DHCP]? Static
          Please enter the IP address to be used for the engine VM [10.37.198.4]:
          Engine VM DNS (leave it empty to skip) [10.37.192.157]:
          Add lines for the appliance itself and for this host to /etc/hosts on the engine VM?
          Note: ensuring that this host could resolve the engine VM hostname is still up to you
          (Yes, No)[No] Yes
          Please provide the name of the SMTP server through which we will send notifications [localhost]:
          Please provide the TCP port number of the SMTP server [25]:
          Please provide the email address from which notifications will be sent [root@localhost]:
          Please provide a comma-separated list of email addresses which will get notifications [root@localhost]:
          Enter engine admin password:
          Confirm engine admin password:
          Please specify the storage you would like to use (glusterfs, iscsi, fc, nfs)[nfs]: glusterfs
          Please specify the full shared storage connection path to use (example: host:/path): dell-r640-04.gluster.tamlab.brq.redhat.com:/engine
          If needed, specify additional mount options for the connection to the hosted-engine storagedomain []: backup-volfile-servers=dell-r640-05.gluster.tamlab.brq.redhat.com:dell-r640-06.gluster.tamlab.brq.redhat.com

'hosted-engine --deploy' does not prompt for a gateway, but the ovirtmgmt bridge is given the 'Default Route' role. The ovirtmgmt network is then out-of-sync. If you navigate to Compute/Hosts/<host>/Network Interfaces/Setup Host Networks and hover over ovirtmgmt it says the DC and the host are out-of-sync on whether this is a default route:
"Host network's configurations differ from DC"
The default route property for the host is set to false, for the DC it is set to true.

Routes on the host:
[root@dell-r640-04 ~]# ip route
default via 10.37.195.254 dev em1 proto dhcp metric 100 
10.37.192.0/22 dev em1 proto kernel scope link src 10.37.192.160 metric 100 
10.37.198.0/25 dev ovirtmgmt proto kernel scope link src 10.37.198.1 
169.254.0.0/16 dev em2 scope link metric 1003 
169.254.0.0/16 dev bond0 scope link metric 1027 
169.254.0.0/16 dev bond0.302 scope link metric 1028 
169.254.0.0/16 dev ovirtmgmt scope link metric 1034 
192.168.1.0/24 dev bond0.302 proto kernel scope link src 192.168.1.4 

DEFROUTE=no on the host for ovirtmgmt:
[root@dell-r640-04 network-scripts]# cat ifcfg-ovirtmgmt
# Generated by VDSM version 4.20.47-1.el7ev
DEVICE=ovirtmgmt
TYPE=Bridge
DELAY=0
STP=off
ONBOOT=yes
IPADDR=10.37.198.1
NETMASK=255.255.255.128
BOOTPROTO=none
MTU=1500
DEFROUTE=no
NM_CONTROLLED=no
IPV6INIT=yes
IPV6_AUTOCONF=yes
DNS1=10.37.192.157

Clicking the 'sync network' button does not resolve it.

I can't remove the 'Default route' property via Compute/Clusters/<cluster>/Logical Networks/Manage Networks - it has to be set on one of the networks. We do want to add another network (tamlab, native VLAN 296 on em2, 10.37.197.0/24) and make that the default route, but it can't be assigned to a host until the networks are synchonized ("Invalid operation, the out-of-sync network 'tamlab' can only be detached").

To sync the networks, on each host, navigate to Compute/Hosts/<host>/Network Interfaces/Setup Host Networks, edit ovirtmgmt, check 'Sync network', and add the gateway (10.37.198.126). The ifcfg files on the host are then updated (GATEWAY, DEFROUTE) and the ovirmgmt network is in sync on that host:

[root@dell-r640-04 network-scripts]# cat ifcfg-ovirtmgmt
# Generated by VDSM version 4.20.47-1.el7ev
DEVICE=ovirtmgmt
TYPE=Bridge
DELAY=0
STP=off
ONBOOT=yes
IPADDR=10.37.198.1
NETMASK=255.255.255.128
GATEWAY=10.37.198.126
BOOTPROTO=none
MTU=1500
DEFROUTE=yes
NM_CONTROLLED=no
IPV6INIT=yes
IPV6_AUTOCONF=yes
DNS1=10.37.192.157

We then have two default routes (one on ovirtmgmt, one on em1):
[root@dell-r640-04 ~]# ip route
default via 10.37.198.126 dev ovirtmgmt 
default via 10.37.195.254 dev em1 proto dhcp metric 100 
10.37.192.0/22 dev em1 proto kernel scope link src 10.37.192.160 metric 100 
10.37.198.0/25 dev ovirtmgmt proto kernel scope link src 10.37.198.1 
169.254.0.0/16 dev em2 scope link metric 1003 
169.254.0.0/16 dev bond0 scope link metric 1027 
169.254.0.0/16 dev bond0.302 scope link metric 1028 
169.254.0.0/16 dev ovirtmgmt scope link metric 1036 
192.168.1.0/24 dev bond0.302 proto kernel scope link src 192.168.1.4 

I can remove the em1 route manually via nmcli.
[root@dell-r640-04 ~]# nmcli con
NAME  UUID                                  TYPE      DEVICE 
em1   a21464ce-2b04-4b94-95eb-91a984cdbeae  ethernet  em1    

After synchonizinging the ovirtmgmt network I can assign the tamlab network to the host.

Note that the cockpit wizard does prompt for a gateway:
Engine VM FQDN: rhvm.rhvmgmt.tamlab.brq.redhat.com
Network Configuration: Static
VM IP Address: 10.37.198.4/25
Gateway Address: 10.37.198.126
DNS Servers: 10.37.192.157
Bridge Interface: em2.297
Number of Virtual CPUs:4 (default)
Memory Size (MiB):16348 (default)
Advanced:
Bridge Name:ovirtmgmt (default)
Host FQDN: dell-r640-04.rhvmgmt.tamlab.brq.redhat.com

Version-Release number of selected component (if applicable):
ovirt-hosted-engine-setup-2.2.34-1.el7ev.noarch

How reproducible:
Haven't tried it yet but it should be reproducible

Steps to Reproduce:
1. hosted-engine --deploy
2.
3.

Actual results:


Expected results:
'hosted-engine --deploy' should prompt for a gateway and synchronize the networks.

Additional info: