10.2. Logical Networks

By default the management network, called rhevm is defined for a data center. New logical networks, for example for data, storage or display can be defined by the administrator. In general, logical networks are created to isolate network traffic by functionality or virtualize a physical topology. In addition, other networks can be used to segregate virtual machine traffic from the management networks, or isolate traffic between groups of virtual machines in the same cluster. In Red Hat Enterprise Virtualization Manager, network definition, type and function are encapsulated in a logical entity called a Logical Network. For example, a data center may have the following networks,
  • Guest data network
  • Storage network access
  • Management network
  • Display network (for SPICE or VNC)


Do not change networking in a data center or a cluster if any hosts are running. This may make the host unreachable.

10.2.1. Adding Logical Networks

A logical network is assigned by an administrator as a required resource of a cluster in a data center. By extension all hosts in a cluster must have the same set of logical networks implemented. The implementation itself may vary from host to host (IP and bonding properties). Therefore, to configure a network, you need to first define the network for a data center and then apply this network to each host in a cluster. By default the management network (rhevm) is defined for a data center.
This section describes how to define a Storage logical network for a data center, apply the Storage logical network to a cluster, and implement the Storage logical network for hosts. This process can be repeated for each logical network being added to a data center.

To define logical networks in a cluster

  1. Navigate to the Tree pane and click the Expand All button. Under System, click select the data center to which a new logical network will be added. On the results list, the selected data center displays.
  2. On the details pane, select the Logical Networks subtab. This displays the existing logical networks. At the minimum, the default rhevm network is listed.
  3. Click New. The New Logical Network dialog displays.
    Add a logical network.

    Figure 10.1. Add a logical network.

    Fill in the Name and Description fields, and select the desired cluster from the Assign Networks to Cluster(s) section, to automatically add the Storage network to the cluster.
  4. Click OK to create the new logical network.
You have defined this network as a resource required by the a cluster in the data center. You can now add this resource to the hosts in the cluster.

To add network to hosts

  1. Back on the Tree pane, click DefaultClustersDefaultHosts. The Hosts tab displays a list of available hosts.
  2. For each of your installed hosts, perform the following tasks:
    1. Click on the host. On the details pane, select the Network Interfaces tab.
    2. A list of network interfaces available for this host displays. One of them will already have the management network (rhevm) configured.
    3. Select the interface on which to configure the newly added network and click the Add/Edit button. The Edit Network Interface dialog displays.
      Edit network interface

      Figure 10.2. Edit network interface

      Configure the following options:
      • Under Network, select your newly created storage network.
      • Select the Static or DHCP radio button. If static was selected, enter the IP and Subnet Mask you have prepared as part of the prerequisites to this procedure.
      • Select the Save network configuration checkbox.
    4. Click OK.
You have now added a new Storage network to your data center. On the Logical Networks tab of the Default data center, you should have at least two networks - rhevm and Storage. You can repeat this process for each logical network being added to a data center Designate Display Network

A logical network created to carry display traffic must be designated as the Display Network using the Red Hat Enterprise Virtualization Manager administration portal.

To designate a new logical network as the display network

  1. Select the Clusters tab, and select the cluster you wish to designate a display network for.
  2. Select the Logical Networks.
  3. Select the logical network that you wish to designate as the Display network.
  4. Click the Set as Display button.
  5. Update Display Network displays in the Events tab.
You have successfully designated a logical network as the display network.