29-10-2009, 02:11 PM
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Abstract
Linux Virtual Server is a high-performance and highly scalable server built on a cluster of real servers. The architecture of the cluster is transparent to end-users. End users only see a single virtual server. The front-end before the real servers is a load balancer, which schedules requests to the different servers and make parallel services of the cluster to appear as a virtual service on a single IP address. Linux Virtual Server is added as a patch to the Linux Kernel. Modifications and additions are made to the existing kernek source to bring about Virtual Server functionalities. Mainly, the IP masquerading functionality is being modified to implement the Virtual Server support. The LVS handles connections from clients and passes them onto the real servers (so-called Layer 4 switching) and can virtualized almost any TCP or UDP service. It uses NAT (Network Address Translation) to achieve IP level load balancing. Round robin scheduling algorithm is used. Transparently adding or removing a node in the cluster achieves scalability.
