Possible to have a single bond for the rhevm network and other tagged networks?

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OK so I install RHEV hypervisor on bare metal, configure the initial network settings using the console and register the host with RHEVM. Once the host is in RHEVM I use the GUI to configure the remaining networks that will be used by VMs.


My question is:

At this point can I create a single bonded interface that will be used for the management network (called 'rhevm') and multiple tagged VLAN interfaces?


It looks like the 'rhevm' network must be on a separate network interface from any of the other networks, is this correct?


Many thanks,


Hi Peta,


I think you are right. I tested this as well and you can only configure a VLAN by creating a Logical Network. You can only configure one VLAN per Logical Network, so you could put the rhem network on one VLAN, but not more than one.


The rhevm logical network is the default network and will always be used for management of the hosts and also for VM migration. Since this network is used for VM migration it is best to put the VMs on a separate logical network in order to segment the traffic.


I'm also not sure why you would need one logical network to be on more than one VLAN. If that is the case you might be able to just configure the VLANs from within the VMs instead of managing it on the RHEV side.


You will probably find this kbase to be very helpful as well:


RHEV: What are the supported networking layouts?



John Brier

Global Support Services - NA



I have tested and implement this exactly in a Proof-of-Concept.


The idea is to use the created bond for additional management LANs for the VMs.


It is possible to create the following scenario:



             <bond0> <bond.<VLAN_ID_1><rhevm>





This solution can be implemented by the following configuration:

1. create an data center in the RHEV Manager GUI

2. change the rhevm-management options and add the VLAN ID to it

3. create the desired network configuration on the hypervisor

4. add the system


now you are able to add further VLANs on the hypervisors and in the GUI in the maintance mode of the hypervisor.


this was only an test environment where I have created this network configuration for an Proof-of-Concept.

but have in mind this has to be checked and to be approved by the support.

You have to set up initial connection between the host and the RHEV Manager before you can actually add other networks. The only prerequisites is that if you need to use a VLAN on the management network (rhevm), you need to configure it before the hosts is added to RHEV Manager.

For RHEV-Hypervisor it's easy, as you just need to add VLAN tag through the setup menu. For RHEL based host, this means that you'll have to set up rhevm network manually before the installation phase done from the RHEV Manager side, otherwise it can't be reached in the first place.

After this, adding a bond and additional VLAN tagged networks can be done from the management GUI.


Please see my comment to the initiatior of this thread.


It sounds like you are configuring multiple VLANs on top of the bond interface manually on the hypervisor at this step:

  1. create the desired network configuration on the hypervisor

is that correct?

and what about this step:

"now you are able to add further VLANs on the hypervisors and in the GUI in the maintance mode of the hypervisor."

What are the details here?

When you configure an host NIC to use a logical network, AFAIK you can only select one logical network:


So to make things clear

rhevm network can coexist with other logical networks on the same NIC or Bond!
This however requires that the rhevm network to be on top of a VLAN.

It is your responsibility that the RHEV-Manager server has a rout to this VLAN or is already located on this VLAN (You can achieve that using any standard RHEL Networking Or Switching layer) 

The rest of the steps are:

  1. Before you add the first host to the Data Center, edit the rhevm network and define a VLAN tag for it
  2. Now for each host:
    1.    If it's a RHEV-Hypervisor host, make sure you set the VLAN tag when configuring the management network in the setup menue
    2.    If it's a RHEL based host, you'll have to create the VLAN and bridge manually using ifcfg scripts.
    3. Now add the hosts to RHEV-Manager
  3. After the hosts are added to RHEV Manager then you can bond the NIC with other NICs using the Edit Management Network button and add more VLAN tagged logical networks by using the Edit/Add button.

OK thanks everyone, I'll give this method a try when I re-install for the next beta release.


Did anyone actually test this method? I just tried it and I still can't work out how to do it. Here is what I did:


1. Create a new DC and assign a VLAN ID to the rhevm network.

2. Build 2 new RHEVH hosts and configure their management interface with a VLAN ID using the console menu before adding to RHEVM.

3. In RHEVM the 2 HVs have their 'rhevm' network as a tagged VLAN on eth0.


But at this point I cannot bond eth0 with another interface. The GUI greys out the bond button when I select eth0 and any other interface. Furthermore, the GUI won't let me add any other tagged VLANs to eth0 (but it will on another interface). It seems it will not let you bond an interface that has tagged VLANs on it. Maintenance mode makes no difference.


So I'm still not sure if this is possible or not. Has anyone else actually been able to achieve this network layout?

Any help or ideas appreciated.




> But at this point I cannot bond eth0 with another interface.


If you have done eth0 -> eth0.x -> rhevm already, then you will not be able to bond eth0 from the above and another ethx from RHEV-M GUI.

To bond two interfaces via rhevm, you need to select eth0 (before adding any tag on it though eth0 can be part of a logical network without any vlan like eth0 -> rhevm) + ethx and make bond0. Then tag bod0 to bond0.vlanid.


Will this get resolved if we allow bonding from RHEV-H installation menu itself for rhevm network? If yes, I request you to open an RFE for that.


> Furthermore, the GUI won't let me add any other tagged VLANs to eth0 (but it will on another interface).


The above is also correct. To add more vlan tags to an interface, it need to be done via "Add/Edit" button on the GUI. If we select the rhevm network, then the "Add/Edit" button will not be active. Only "Edit Management Network" will be active. Through "Edit Management Network", we cannot add more vlan tags to that interface.

A separate RFE need to be file for this as well.


Yes, this is all correct. I'm glad we are on the same page here.

If you click on the "rhevm" (which is already tagged) network under Hosts and selecting a specific host, do you see both "Add / Edit Vlan" and "Edit Management Network" button active or only the latter one?

Only the latter.

I am going to open an RFE for this. Even if this type of network configuration is possible in some sort of convoluted manner, it should be dead simple to configure.

There are a lot of VLANs in our network (management and projects).


I've tested:


1) two NICs -> bond -> different tagged VLANs eths -> bridges (rhevm + spice + .....)


Currently we're using one NICs for tagged rhevm network and another NIC for display network and project VLANs (all VLANs are tagged). It works with RHEV-H as well as with RHEL hosts

Both the issues are resolved in the below errata.




You will now be able to bond a vlan tagged logical network and add more vlan tags on rhevm logical network.

I have been watching this tread with interest. I have applied the updates to a fresh rhev 3 install and still cannot attach any other vlans to the existing tagged rhevm interface.

I catually tested this myself it should work, I did it on the relase candidate of 3.0.3, make sure this is your version.



  1. Upgraded my setup Added Vlan x on the RHEV Manager's server
  2. Added Vlan x on the host and placed the rhevm bridge on top
  3. Created a new DC
  4. Edit the rhevm network to have VLAN tag x
  5. Created a cluster
  6. Added the host
  7. Now there is a VLAN tag on the RHEV-Manager network
  8. Bond the interface on which rhevm is configured with another interface - WORKS!!!
  9. Created new Logical network in the DC, set tag y, and attache to the cluster
  10. Add Vlan y tagged network on top of this bond - WORKS!!!

Following this procedure I noticed that when selecting an Active/Backup bond,  the link is reported to be Active/Backup in RHEV-M, but operates in load balancing (round-robin) mode until the hypervisor (6.3) is rebooted. This caused some packet loss and headscratching.   

If you are not able to make it working by following the steps given by Simon, please open a case with Red Hat support.