Dear Soeren, dear all, Thank you very much. I did try the steps on an installed system. The result was that after manipulating the network scripts, the server would communicate well with the rest of the LAN - as many other servers on which I use NIC bonds. However, my hosted-engine refused to start: "hosted-engine --vm-start" results in "Connection to localhost:54321 refused". Needless to say, it is not possible to revert the maintenance mode then. ABRT points out what the problem is (but not the solution): "api.py:119:objectivizeNetwork:ConfigNetworkError: (24, u'nic enp0s20f1 already enslaved to bond0')" This shows that oVirt cannot start after the manipulation of network scripts as it does expect enp0s20f1 no not be a slave of a bond. Naming of the devices becomes clear from the following paragraph. After multiple failed experiments to set up the server with bonded NIC (each implying configuring the server from scratch), I took the following approach this time: - The server has two LAN facing NICs enp0s20f0, enp0s20f1. The other two NICs point to the other server in the intended gluster cluster - creating a bond for them is not problematical. - Setting up Centos 7, I just used enp0s20f0 with no bond and bridge. - Deploying oVirt one gets asked for an unused NIC, so I selected enp0s20f1. Then the network was only resting on enp0s20f1 with a working setup of oVirt - just without bonding two NICs. I am still surprised that this HA network issue is so difficult to manage in a software that is largely about high availability. Can anyone please indicate how to proceed towards NIC bonding? Regards, Michael Network Scripts as set manually: DEVICE=enp0s20f0 TYPE=Ethernet USERCTL=no SLAVE=yes MASTER=bond0 BOOTPROTO=none HWADDR=00:25:90:F5:18:9A NM_CONTROLLED=no DEVICE=enp0s20f1 TYPE=Ethernet USERCTL=no SLAVE=yes MASTER=bond0 BOOTPROTO=none HWADDR=00:25:90:F5:18:9B NM_CONTROLLED=no DEVICE=bond0 ONBOOT=yes BONDING_OPTS='mode=802.3ad miimon=100' BRIDGE=ovirtmgmt NM_CONTROLLED=no DEVICE=ovirtmgmt ONBOOT=yes TYPE=Bridge IPADDR=192.168.12.40 NETMASK=255.255.255.0 GATEWAY=192.168.12.1 DNS=192.168.12.1 NM_CONTROLLED=no -----Ursprüngliche Nachricht----- Von: Soeren Malchow [mailto:soeren.malchow@mcon.net] Gesendet: Montag, 6. Juli 2015 15:01 An: Prof. Dr. Michael Schefczyk; users(a)ovirt.org Betreff: Re: [ovirt-users] oVirt 3.5.3 Host Network Interfaces Dear Michael We actually created the ovirtmgmt and the bond manually upfront and then in the ³Setup Hosts Network² we basically did this again (including setting the IP address), regarding the bonding in the gluster network we did not have a problem, you just drag one interface onto the other and then select the bonding mode, where you can also go for bonding mode TLB or ALB if you choose ³custom² or just LACP if you have switches that support this. Step by Step: - set the engine to maintenance and shut it down - configure the bond on the 2 nics for the ovirtmgmt bridge ( em1+em2 -> bond0 -> ovirtmgmt ) - configure the IP on the bridge - reboot the server and see whethter it comes up correctly - remove maintenance and let engine start - Set up the ovirtmgmt in hosts networks but do not forget to set IP and Gateway as well. Though it should work without this hassle (if the bonding mode on the switch and server is compatible) but this way it is easy to get server and switch in the same mode and working without having to do anything in ovirt first. Hope that helps Regards Soeren On 02/07/15 00:31, &quot;users-bounces(a)ovirt.org on behalf of Prof. Dr. Michael Schefczyk" <users-bounces(a)ovirt.org on behalf of michael(a)schefczyk.net&gt; wrote: