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How do I configure the rhevm (management) network on a bonded and possibly VLAN tagged interface?

Updated 2013-11-15T08:47:09+00:00

Issue

  • The procedure for setting up the Red Hat Enterprise Virtualization (RHEV) management network on a bonded/VLAN interface differs from the procedure used when setting up a standard bonded/VLAN network configuration. How do I configure this?

Environment

  • Red Hat Enterprise Virtualization (RHEV) 2.2, 3.0, 3.1

Resolution

Note: On RHEV 3.2 and above, this procedure is no longer required. The "rhevm" logical network attached to the Default Data Center can be edited. The only manual configuration needed in 3.2 is the initial NIC device + vlan that will connect the host/hypervisor to the RHEV-M. Once the host is added into RHEV-M, everything else can be done from the Admin Portal.

Step 1: In the Admin Portal

If the "rhevm" network is tagged, the Admin Portal GUI will show eth0.x (x being the VLAN number) as the interface "rhevm" is attached to. For bonding, eth0 and not eth0.x should be used.

No VLAN RHEVM on Bond-Only configuration:
  1. Log in to the Admin Portal and switch to the Hosts tab.
  2. Open the Network Interfaces sub-tab after selecting the host.
  3. Ctrl+click eth0 (already marked with the "rhevm" network attached) and the additional NIC(s) to be bonded.
  4. Click the Bond button.
  5. Make sure the "Check Connectivity" checkbox is unchecked. Provide the bonding options if relevant.
  6. Click OK.
RHEVM on VLAN Configuration:
  1. In the Admin Portal, under the Data Center tab, enable VLAN tagging on the Logical Network sub-tab.
  2. Create a new Data Center (DC). Do not use the default. (Currently, it is not possible to edit the rhevm network properties when there are already Clusters in a Data Center, which is the case with the Default DC).
  3. Edit the rhevm network to have the desired VLAN tag. (In RHEV 2.2, there is a bug on this step - the dialog box may show an error saying that rhevm network could not be detached from the clusters. - There are no clusters in this DC at this time. Just ignore the message.)
  4. Create a cluster in the new DC.
  5. Add the host to the cluster. It should have rhevm logical network sitting on VLAN. Next, join it to a bond with another interface as described above.

Step 2: On the Host

If the goal is to configure multiple VLAN-tagged logical networks in RHEV, follow the steps in this article using only the "rhevm" network first. Once the "rhevm" network has been bonded and VLAN tagged, then adding additional logical networks on additional VLAN tagged networks will be possible using the AdminPortal interface.

  • Set up the "rhevm" network on a single interface. This example uses eth0.
  • If a RHEV-H host is used, follow the configuration menu and provide a VLAN tag number when configuring the management network, if a VLAN tag on the management network is required.
  • If a RHEL host is used, the tagging will be set up automatically when the host is added to the RHEV setup.

Repeat Step 2 for any hosts added to this Data Center.

Root Cause

This procedure is needed on RHEV 2.2, 3.0, and 3.1 because, by default, after installation of RHEV-M, a default cluster is populated in the Default Data Center. Because that cluster already exists, the already-attached "rhevm" network cannot be edited.

Diagnostic Steps

After completing the above configuration steps, it is possible to have lost connection to the RHEV-H node and the configuration will not complete. There are several possible reasons for this:

  1. The interface bond0 will be created and the "rhevm" network will be moved onto the bond. If the switch is not configured or the NICs aren't all connected, then it is possible that the bond will initially contain an unconnected NIC, and then the RHEV-M will lose contact and be unable to add the working NIC. This can be resolved by logging in to the RHEV-H console and continuing the configuration manually.
  2. The "GATEWAY" parameter might be missed from the configuration files due to RHBZ#815415.
  3. In the case where a VLAN tag is involved, the structure will be bond0 > bond0.x > rhevm.
    This will happen only if the "rhevm" network is set up in the RHEV Admin GUI with a tag, which should be done when the Data Center is in an uninitialized state, before the rest of the configuration takes place. Otherwise, setting the VLAN tag should be done manually.

To configure the VLAN networks manually, log in to the RHEV-H console and configure as follows:

  • Ensure that the VLAN tagged NIC is not enabled, e.g. remove ifcfg-eth0.4.
  • Ensure that configuration files for bonded and VLAN tagged bonded interfaces exist separately. e.g. bond0 and bond0.4
  • Ensure that only the VLAN tagged bonded interface contains the "VLAN" and "BRIDGE" keywords. e.g. ifcfg-bond0.4 should contain VLAN=yes and BRIDGE=rhevm