The GLOBAL SETTINGS panel is where the cluster administrator defines the networking details for the primary LVS router's public and private network interfaces.


Figure 4.3. The GLOBAL SETTINGS Panel

The top half of this panel sets up the primary LVS router's public and private network interfaces. These are the interfaces already configured in Section 3.1.1, “Configuring Network Interfaces for a NAT LVS Cluster”.

Primary server public IP

In this field, enter the publicly routable real IP address for the primary LVS node.

Primary server private IP

Enter the real IP address for an alternative network interface on the primary LVS node. This address is used solely as an alternative heartbeat channel for the backup router and does not have to correlate to the real private IP address assigned in Section 3.1.1, “Configuring Network Interfaces for a NAT LVS Cluster”. You may leave this field blank, but doing so will mean there is no alternate heartbeat channel for the backup LVS router to use and therefore will create a single point of failure.


The private IP address is not needed for Direct Routing configurations, as all real servers as well as the LVS directors share the same virtual IP addresses and should have the same IP route configuration.


The primary LVS router's private IP can be configured on any interface that accepts TCP/IP, whether it be an Ethernet adapter or a serial port.

Use network type

Click the NAT button to select NAT routing.

Click the Direct Routing button to select direct routing.

The next three fields deal specifically with the NAT router's virtual network interface connecting the private network with the real servers. These fields do not apply to the direct routing network type.

NAT Router IP

Enter the private floating IP in this text field. This floating IP should be used as the gateway for the real servers.

NAT Router netmask

If the NAT router's floating IP needs a particular netmask, select it from drop-down list.

NAT Router device

Use this text field to define the device name of the network interface for the floating IP address, such as eth1:1.


You should alias the NAT floating IP address to the Ethernet interface connected to the private network. In this example, the private network is on the eth1 interface, so eth1:1 is the floating IP address.


After completing this page, click the ACCEPT button to make sure you do not lose any changes when selecting a new panel.

Note: This documentation is provided {and copyrighted} by Red Hat®, Inc. and is released via the Open Publication License. The copyright holder has added the further requirement that Distribution of substantively modified versions of this document is prohibited without the explicit permission of the copyright holder. The CentOS project redistributes these original works (in their unmodified form) as a reference for CentOS-4 because CentOS-4 is built from publicly available, open source SRPMS. The documentation is unmodified to be compliant with upstream distribution policy. Neither CentOS-4 nor the CentOS Project are in any way affiliated with or sponsored by Red Hat®, Inc.