Installation guide

Figure 1.1. A Basic LVS Configuration
Service requests arriving at the LVS routers are addressed to a virtual IP address, or VIP. This
is a publicly-routable address the administrator of the site associates with a fully-qualified
domain name, such as www.example.com, and is assigned to one or more virtual servers. A
virtual server is a service configured to listen on a specific virtual IP. Refer to Section 6,
“VIRTUAL SERVERS” for more information on configuring a virtual server using the Piranha
Configuration Tool. A VIP address migrates from one LVS router to the other during a failover,
thus maintaining a presence at that IP address (also known as floating IP addresses).
VIP addresses may be aliased to the same device which connects the LVS router to the
Internet. For instance, if eth0 is connected to the Internet, than multiple virtual servers can be
aliased to eth0:1. Alternatively, each virtual server can be associated with a separate device
per service. For example, HTTP traffic can be handled on eth0:1, and FTP traffic can be
handled on eth0:2.
Only one LVS router is active at a time. The role of the active router is to redirect service
requests from virtual IP addresses to the real servers. The redirection is based on one of eight
supported load-balancing algorithms described further in Section 3, “LVS Scheduling Overview”.
Chapter 1. Linux Virtual Server Overview
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