11.4. Editing Logical Networks
- 11.4.1. Editing Host Network Interfaces and Assigning Logical Networks to Hosts
- 11.4.2. Logical Network General Settings Explained
- 11.4.3. Editing a Logical Network
- 11.4.4. Explanation of Settings in the Manage Networks Window
- 11.4.5. Adding Multiple VLANs to a Single Network Interface Using Logical Networks
- 11.4.6. Multiple Gateways
- 11.4.7. Using the Networks Tab
11.4.1. Editing Host Network Interfaces and Assigning Logical Networks to Hosts
Summary
You can change the settings of physical host network interfaces, move the management network from one physical host network interface to another, and assign logical networks to physical host network interfaces.
Important
You cannot assign logical networks offered by external providers to physical host network interfaces; such networks are dynamically assigned to hosts as they are required by virtual machines.
Procedure 11.2. Editing Host Network Interfaces and Assigning Logical Networks to Hosts
- Use the Hosts resource tab, tree mode, or the search function to find and select the host in the results.
- Click the Network Interfaces tab in the details pane.
- Click the button to open the Setup Host Networks window.
- Attach a logical network to a physical host network interface by selecting and dragging the logical network into the Assigned Logical Networks area next to the physical host network interface.Alternatively, right-click the logical network and select a network interface from the drop-down menu.
- Configure the logical network:
- Hover your cursor over an assigned logical network and click the pencil icon to open the Edit Management Network window.
- Select a Boot Protocol from:
- None,
- DHCP, or
- Static.If you selected Static, enter the IP, Subnet Mask, and the Gateway.
- To configure a network bridge, click the Custom Properties drop-down menu and select . Enter a valid key and value with the following syntax: [key]=[value]. Separate multiple entries with a whitespace character. The following keys are valid, with the values provided as examples:
forward_delay=1500 gc_timer=3765 group_addr=1:80:c2:0:0:0 group_fwd_mask=0x0 hash_elasticity=4 hash_max=512 hello_time=200 hello_timer=70 max_age=2000 multicast_last_member_count=2 multicast_last_member_interval=100 multicast_membership_interval=26000 multicast_querier=0 multicast_querier_interval=25500 multicast_query_interval=13000 multicast_query_response_interval=1000 multicast_query_use_ifaddr=0 multicast_router=1 multicast_snooping=1 multicast_startup_query_count=2 multicast_startup_query_interval=3125
- If your logical network definition is not synchronized with the network configuration on the host, select the Sync network check box. A logical network cannot be edited or moved to another interface until it is synchronized.
Note
Networks are not considered synchronized if they have one of the following conditions:- The VM Network is different from the physical host network.
- The VLAN identifier is different from the physical host network.
- A Custom MTU is set on the logical network, and is different from the physical host network.
- Select the Verify connectivity between Host and Engine check box to check network connectivity; this action will only work if the host is in maintenance mode.
- Select the Save network configuration check box to make the changes persistent when the environment is rebooted.
- Click .
Result
You have assigned logical networks to and configured a physical host network interface.
Note
If not all network interface cards for the host are displayed, click the Refresh Capabilities button to update the list of network interface cards available for that host.
11.4.2. Logical Network General Settings Explained
The table below describes the settings for the General tab of the New Logical Network and Edit Logical Network window.
Table 11.1. New Logical Network and Edit Logical Network Settings
|
Field Name
|
Description
|
|---|---|
|
Name
|
The name of the logical network. This text field has a 15-character limit and must be a unique name with any combination of uppercase and lowercase letters, numbers, hyphens, and underscores.
|
|
Description
|
The description of the logical network. This text field has a 40-character limit.
|
|
Comment
|
A field for adding plain text, human-readable comments regarding the logical network.
|
|
Create on external provider
|
Allows you to create the logical network to an OpenStack Networking instance that has been added to the Manager as an external provider.
External Provider - Allows you to select the external provider on which the logical network will be created.
|
|
Enable VLAN tagging
|
VLAN tagging is a security feature that gives all network traffic carried on the logical network a special characteristic. VLAN-tagged traffic cannot be read by interfaces that do not also have that characteristic. Use of VLANs on logical networks also allows a single network interface to be associated with multiple, differently VLAN-tagged logical networks. Enter a numeric value in the text entry field if VLAN tagging is enabled.
|
|
VM Network
|
Select this option if only virtual machines use this network. If the network is used for traffic that does not involve virtual machines, such as storage communications, do not select this check box.
|
|
MTU
|
Choose either Default, which sets the maximum transmission unit (MTU) to the value given in the parenthesis (), or Custom to set a custom MTU for the logical network. You can use this to match the MTU supported by your new logical network to the MTU supported by the hardware it interfaces with. Enter a numeric value in the text entry field if Custom is selected.
|
|
Network Label
|
Allows you to specify a new label for the network or select from existing labels already attached to host network interfaces. If you select an existing label, the logical network will be automatically assigned to all host network interfaces with that label.
|
11.4.3. Editing a Logical Network
Summary
Edit the settings of a logical network.
Procedure 11.3. Editing a Logical Network
Important
A logical network cannot be edited or moved to another interface if it is not synchronized with the network configuration on the host. See Section 11.4.1, “Editing Host Network Interfaces and Assigning Logical Networks to Hosts” on how to synchronize your networks.
- Use the Data Centers resource tab, tree mode, or the search function to find and select the data center of the logical network in the results list.
- Click the Logical Networks tab in the details pane to list the logical networks in the data center.
- Select a logical network and click to open the Edit Logical Network window.
- Edit the necessary settings.
- Click OK to save the changes.
Result
You have updated the settings of your logical network.
Note
Multi-host network configuration is available on data centers with 3.1-or-higher compatibility, and automatically applies updated network settings to all of the hosts within the data center to which the network is assigned. Changes can only be applied when virtual machines using the network are down. You cannot rename a logical network that is already configured on a host. You cannot disable the VM Network option while virtual machines or templates using that network are running.
11.4.4. Explanation of Settings in the Manage Networks Window
The table below describes the settings for the Manage Networks window.
Table 11.2. Manage Networks Settings
|
Field
|
Description/Action
|
|---|---|
|
Assign
|
Assigns the logical network to all hosts in the cluster.
|
|
Required
|
A Network marked "required" must remain operational in order for the hosts associated with it to function properly. If a required network ceases to function, any hosts associated with it become non-operational.
|
|
VM Network
| A logical network marked "VM Network" carries network traffic relevant to the virtual machine network. |
|
Display Network
| A logical network marked "Display Network" carries network traffic relevant to SPICE and to the virtual network controller. |
|
Migration Network
| A logical network marked "Migration Network" carries virtual machine and storage migration traffic. |
11.4.5. Adding Multiple VLANs to a Single Network Interface Using Logical Networks
Summary
Multiple VLANs can be added to a single network interface to separate traffic on the one host.
Important
You must have created more than one logical network, all with the Enable VLAN tagging check box selected in the New Logical Network or Edit Logical Network windows.
Procedure 11.4. Adding Multiple VLANs to a Network Interface using Logical Networks
- Use the Hosts resource tab, tree mode, or the search function to find and select in the results list a host associated with the cluster to which your VLAN-tagged logical networks are assigned.
- Click the Network Interfaces tab in the details pane to list the physical network interfaces attached to the data center.
- Click to open the Setup Host Networks window.
- Drag your VLAN-tagged logical networks into the Assigned Logical Networks area next to the physical network interface. The physical network interface can have multiple logical networks assigned due to the VLAN tagging.
- Edit the logical networks by hovering your cursor over an assigned logical network and clicking the pencil icon to open the Edit Network window.If your logical network definition is not synchronized with the network configuration on the host, select the Sync network check box.Select a Boot Protocol from:Click OK.
- None,
- DHCP, or
- Static,Provide the IP and Subnet Mask.
- Select the Verify connectivity between Host and Engine check box to run a network check; this will only work if the host is in maintenance mode.
- Select the Save network configuration check box
- Click .
Add the logical network to each host in the cluster by editing a NIC on each host in the cluster. After this is done, the network will become operational
Result
You have added multiple VLAN-tagged logical networks to a single interface. This process can be repeated multiple times, selecting and editing the same network interface each time on each host to add logical networks with different VLAN tags to a single network interface.
11.4.6. Multiple Gateways
Summary
Users can define the gateway, along with the IP address and subnet mask, for a logical network. This is necessary when multiple networks exist on a host and traffic should be routed through the specified network, rather than the default gateway.
If multiple networks exist on a host and the gateways are not defined, return traffic will be routed through the default gateway, which may not reach the intended destination. This would result in users being unable to ping the host.
Red Hat Enterprise Virtualization 3.5 handles multiple gateways automatically whenever an interface goes up or down.
Procedure 11.5. Viewing or Editing the Gateway for a Logical Network
- Use the Hosts resource tab, tree mode, or the search function to find and select the host in the results list.
- Click the Network Interfaces tab in the details pane to list the network interfaces attached to the host and their configurations.
- Click the button to open the Setup Host Networks window.
- Hover your cursor over an assigned logical network and click the pencil icon to open the Edit Management Network window.
Result
The Edit Management Network window displays the network name, the boot protocol, and the IP, subnet mask, and gateway addresses. The address information can be manually edited by selecting a Static boot protocol.
11.4.7. Using the Networks Tab
The Networks resource tab provides a central location for users to perform network-related operations and search for networks based on each network's property or association with other resources.
All networks in the Red Hat Enterprise Virtualization environment display in the results list of the Networks tab. The , and buttons allow you to create, change the properties of, and delete logical networks within data centers.
Click on each network name and use the Clusters, Hosts, Virtual Machines, Templates, and Permissions tabs in the details pane to perform functions including:
- Attaching or detaching the networks to clusters and hosts
- Removing network interfaces from virtual machines and templates
- Adding and removing permissions for users to access and manage networks
These functions are also accessible through each individual resource tab.

