While Red Hat Enterprise Linux can be configured in a variety of
different ways, the configurations can be broken into two major
categories:
This part explains what a load-balancing cluster system is and
how to configure a load-balancing system using Linux Virtual Servers on Red Hat Enterprise
Linux.
To an outside user accessing a hosted service (such as a website
or database application), a Linux Virtual Server (LVS) cluster
appears as one server. In reality, however, the user is actually
accessing a cluster of two or more servers behind a pair of
redundant LVS routers that distribute client requests evenly
throughout the cluster system. Load-balanced clustered services
allow administrators to use commodity hardware and Red Hat
Enterprise Linux to create continuous and consistent access to all
hosted services while also addressing availability
requirements.
An LVS cluster consists of at least two layers. The first layer
is composed of a pair of similarly configured Linux machines or
cluster members. One of these machine acts
as the LVS routers, configured to direct
requests from the Internet to the cluster. The second layer
consists of a cluster of machines called real
servers. The real servers provide the critical services to the
end-user while the LVS router balances the load on these
servers.
For a detailed overview of LVS clustering, refer to Chapter 7 Linux Virtual Server
Overview.
