1.4. 路​​​​​​​由​​​​​​​方​​​​​​​法​​​​​​​

图 1.3 “LVS Implemented with NAT Routing”, illustrates LVS utilizing NAT routing to move requests between the Internet and a private network.

在​​​​​​​本​​​​​​​示​​​​​​​例​​​​​​​中​​​​​​​，活​​​​​​​跃​​​​​​​ LVS 路​​​​​​​由​​​​​​​器​​​​​​​中​​​​​​​有​​​​​​​两​​​​​​​个​​​​​​​ NIC。​​​​​​​用​​​​​​​于​​​​​​​互​​​​​​​联​​​​​​​网​​​​​​​的​​​​​​​ NIC 在​​​​​​​ eth0 中​​​​​​​有​​​​​​​一​​​​​​​个​​​​​​​真​​​​​​​实​​​​​​​ IP 地​​​​​​​址​​​​​​​，并​​​​​​​有​​​​​​​一​​​​​​​个​​​​​​​别​​​​​​​名​​​​​​​为​​​​​​​ eth0:1 的​​​​​​​浮​​​​​​​动​​​​​​​ IP 地​​​​​​​址​​​​​​​。​​​​​​​用​​​​​​​于​​​​​​​专​​​​​​​用​​​​​​​网​​​​​​​络​​​​​​​接​​​​​​​口​​​​​​​的​​​​​​​ NIC 在​​​​​​​ eth1 中​​​​​​​有​​​​​​​一​​​​​​​个​​​​​​​真​​​​​​​实​​​​​​​ IP 地​​​​​​​址​​​​​​​，并​​​​​​​有​​​​​​​一​​​​​​​个​​​​​​​别​​​​​​​名​​​​​​​为​​​​​​​ eth1:1 的​​​​​​​浮​​​​​​​动​​​​​​​ IP 地​​​​​​​址​​​​​​​。​​​​​​​在​​​​​​​发​​​​​​​生​​​​​​​失​​​​​​​效​​​​​​​切​​​​​​​换​​​​​​​时​​​​​​​，面​​​​​​​向​​​​​​​互​​​​​​​联​​​​​​​网​​​​​​​的​​​​​​​虚​​​​​​​拟​​​​​​​接​​​​​​​口​​​​​​​和​​​​​​​面​​​​​​​向​​​​​​​虚​​​​​​​拟​​​​​​​接​​​​​​​口​​​​​​​的​​​​​​​专​​​​​​​用​​​​​​​接​​​​​​​口​​​​​​​同​​​​​​​时​​​​​​​由​​​​​​​备​​​​​​​用​​​​​​​ LVS 路​​​​​​​由​​​​​​​器​​​​​​​取​​​​​​​代​​​​​​​。​​​​​​​所​​​​​​​有​​​​​​​位​​​​​​​于​​​​​​​专​​​​​​​用​​​​​​​网​​​​​​​络​​​​​​​中​​​​​​​的​​​​​​​真​​​​​​​实​​​​​​​服​​​​​​​务​​​​​​​器​​​​​​​为​​​​​​​ NAT 路​​​​​​​由​​​​​​​器​​​​​​​使​​​​​​​用​​​​​​​浮​​​​​​​动​​​​​​​ IP 地​​​​​​​址​​​​​​​，因​​​​​​​为​​​​​​​它​​​​​​​们​​​​​​​默​​​​​​​认​​​​​​​路​​​​​​​由​​​​​​​是​​​​​​​和​​​​​​​活​​​​​​​跃​​​​​​​ LVS 路​​​​​​​由​​​​​​​器​​​​​​​沟​​​​​​​通​​​​​​​，以​​​​​​​便​​​​​​​不​​​​​​​会​​​​​​​影​​​​​​​响​​​​​​​到​​​​​​​对​​​​​​​来​​​​​​​自​​​​​​​互​​​​​​​联​​​​​​​网​​​​​​​请​​​​​​​求​​​​​​​的​​​​​​​回​​​​​​​应​​​​​​​。​​​​​​​

In this example, the LVS router's public LVS floating IP address and private NAT floating IP address are aliased to two physical NICs. While it is possible to associate each floating IP address to its own physical device on the LVS router nodes, having more than two NICs is not a requirement.

使​​​​​​​用​​​​​​​这​​​​​​​种​​​​​​​布​​​​​​​局​​​​​​​，活​​​​​​​跃​​​​​​​ LVS 路​​​​​​​由​​​​​​​器​​​​​​​可​​​​​​​接​​​​​​​收​​​​​​​请​​​​​​​求​​​​​​​并​​​​​​​将​​​​​​​其​​​​​​​路​​​​​​​由​​​​​​​到​​​​​​​适​​​​​​​当​​​​​​​的​​​​​​​服​​​​​​​务​​​​​​​器​​​​​​​。​​​​​​​然​​​​​​​后​​​​​​​真​​​​​​​实​​​​​​​服​​​​​​​务​​​​​​​器​​​​​​​处​​​​​​​理​​​​​​​该​​​​​​​请​​​​​​​求​​​​​​​并​​​​​​​将​​​​​​​数​​​​​​​据​​​​​​​包​​​​​​​返​​​​​​​回​​​​​​​到​​​​​​​ LVS 路​​​​​​​由​​​​​​​器​​​​​​​，该​​​​​​​路​​​​​​​由​​​​​​​器​​​​​​​使​​​​​​​用​​​​​​​网​​​​​​​络​​​​​​​地​​​​​​​址​​​​​​​转​​​​​​​换​​​​​​​将​​​​​​​数​​​​​​​据​​​​​​​包​​​​​​​中​​​​​​​的​​​​​​​真​​​​​​​实​​​​​​​服​​​​​​​务​​​​​​​器​​​​​​​地​​​​​​​址​​​​​​​替​​​​​​​换​​​​​​​为​​​​​​​ LVS 路​​​​​​​由​​​​​​​器​​​​​​​公​​​​​​​共​​​​​​​ VIP 地​​​​​​​址​​​​​​​。​​​​​​​这​​​​​​​个​​​​​​​过​​​​​​​程​​​​​​​被​​​​​​​称​​​​​​​为​​​​​​​ IP 伪​​​​​​​装​​​​​​​，因​​​​​​​为​​​​​​​发​​​​​​​出​​​​​​​请​​​​​​​求​​​​​​​的​​​​​​​客​​​​​​​户​​​​​​​端​​​​​​​无​​​​​​​法​​​​​​​看​​​​​​​到​​​​​​​真​​​​​​​实​​​​​​​服​​​​​​​务​​​​​​​器​​​​​​​的​​​​​​​实​​​​​​​际​​​​​​​ IP 地​​​​​​​址​​​​​​​。​​​​​​​

使​​​​​​​用​​​​​​​这​​​​​​​种​​​​​​​ NAT 路​​​​​​​由​​​​​​​，真​​​​​​​实​​​​​​​服​​​​​​​务​​​​​​​器​​​​​​​可​​​​​​​以​​​​​​​是​​​​​​​运​​​​​​​行​​​​​​​各​​​​​​​种​​​​​​​操​​​​​​​作​​​​​​​系​​​​​​​统​​​​​​​的​​​​​​​机​​​​​​​器​​​​​​​。​​​​​​​最​​​​​​​大​​​​​​​的​​​​​​​缺​​​​​​​点​​​​​​​就​​​​​​​是​​​​​​​在​​​​​​​较​​​​​​​大​​​​​​​群​​​​​​​集​​​​​​​部​​​​​​​署​​​​​​​中​​​​​​​ LVS 路​​​​​​​由​​​​​​​器​​​​​​​可​​​​​​​能​​​​​​​会​​​​​​​成​​​​​​​为​​​​​​​瓶​​​​​​​颈​​​​​​​，因​​​​​​​为​​​​​​​它​​​​​​​必​​​​​​​须​​​​​​​处​​​​​​​理​​​​​​​外​​​​​​​发​​​​​​​和​​​​​​​进​​​​​​​入​​​​​​​请​​​​​​​求​​​​​​​。​​​​​​​