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5. Configure Logical Networks

Now that you have a data center with hosts grouped in a cluster, you need to define and apply the networking layer. When you installed the system, a management network was already defined. However new networks, for example data, storage or display can be added to enhance network speed and performance. 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.
A logical network is assigned as a required resource of a cluster in a data center, and 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 and then apply this network to each host. By default the management network (rhevm) is defined for a data center.
In this lab, you will create an additional storage network and add it to your hosts. In the following example you will define additional network for the storage, which will be useful when using NAS storage like NFS or iSCSI.
To define logical networks in a cluster
  1. Navigate to the Tree pane and click the Expand All button. Under System, click Default. On the results list, the Default data center displays.
  2. On the details pane, select the Logical Networks subtab. This displays the existing logical networks. At this stage only the default rhevm network is listed.
  3. Click New. The New Logical Network dialog displays.
    New Logical Network
    Figure 10. New Logical Network

    Fill in the Name and Description fields, and tick the Assign Networks to Cluster(s) - Default checkbox to automatically add the Storage network to the Default data center.
  4. Click OK to create the new logical network.
Now that you have defined this network as a resource required by the default cluster in the data center, it is time to 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.
      Available network interfaces
      Figure 11. Available network interfaces

    3. Select the interface on which to configure the Storage network and click the Edit/ Add VLAN button. The Edit Network Interface dialog displays.
      Edit network interface
      Figure 12. Edit network interface

      Configure the following options:
      • Under Network, select your newly created storage network.
      • Select the Static radio button. Enter the IP and Subnet Mask you have prepared as part of the prerequisites to this lab.
      • Tick the Save network configuration checkbox.
    4. Click OK.
You have now added a new storage network to your data center, and attached the network to your hosts. On the Logical Networks tab of the Default data center, you should have at least two networks - rhevm and storage. Now, you can add storage to the system.