Topologies

Load Balancing

This topology focuses on providing a load balanced service with minimal hardware requirements. Real Servers may be added as additional serving resources are required. A sample configuration is available.

• Linux Director

  The Linux Director acts as the gateway router for the network and load balances traffic using LVS. The linux director would typically be fitted with two Network Interface Cards (NICs). Optionally, the linux director may have packet filtering enabled to control the traffic which is able to enter and leave the server network. When configuring LVS to forward packets using NAT, RFC 1918 private addresses may be used to reduce the number of externally routable IP addresses required as the return path for the Real Servers is through the linux director.

  When a linux director receives a connection from an end user it makes a decision on which Real Server to forward the connection to. All packets for the life of this connection will be forwarded to the same real server so the integrity of the connection between the end user and the real server is maintained.

  Ldirectord monitors the health of the real servers by periodically requesting a known page and checking that the response contains an expected string. If a real server fails then the server is taken out of the pool of real servers and will be reinserted once it comes back on line.

• Real Servers

  The Real Servers may run a variety of services including The Apache HTTP Server. Additional real servers may be added to the network as extra capacity is required.

Copyright © 2000-2005, Horms
Last Updated: Tue May 17 17:37:24 2005 +0900

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