Lvs-nat Model Demo

Project background: LVS is the abbreviation for Linux virtual server, that is, the Lvs-nat model is a model of load balancing technology, so let's take a look at this lvs-nat.

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Tentative external client IP is CIP

When the client requests the message arrives the director, the original IP is CIP, the target IP is the VIP, once the director discovers the client request is a Cluster service, uses the pre-defined scheduling algorithm, through the NAT address transformation, arrives at the backend one realserver, Assuming the Realserver1 is selected, the original IP is CIP, the target IP is RIP1, when RIP1 received, and then reply, at this time the original IP is RIP1, the target IP is CIP, when the message arrives Director,director and then through the NAT address translation, The destination IP is unchanged, the original IP is changed to VIP, and then sent out, because CIP does not request RIP1, if not converted, CIP will not receive this message, so the last step is required.

Let's take a concrete demonstration:

Client CIP (that is, native windows): 169.254.179.60

VIP: 169.254.179.1

DIP: 192.168.2.140

RIP1: 192.168.2.141

RIP2: 192.168.2.143

Operating environment VMware Workstation 9 redhat6.2

Note: To avoid other distractions, turn off the 3 iptables and set the SELinux to 0.

1 Installing the Ipvsadm:

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2 Defining the Cluster service

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3 Adding Realserver

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4 on Realserver1 and Realserver2 respectively on the httpd service, respectively set up a different home page, for testing the distinction, and the gateway point to dip

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realserver2:650) this.width=650; "Src=" http://s1.51cto.com/wyfs02/M00/7C/E5/ Wkiom1bbpedczbxfaaaajvdv_cg098.png "title=" 143 httpd. PNG "alt=" Wkiom1bbpedczbxfaaaajvdv_cg098.png "/>

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5 Turn on the director's Network card forwarding function

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7 View defined Cluster service 650) this.width=650; "Src=" Http://s5.51cto.com/wyfs02/M02/7C/E5/wKiom1bbqWmiE2psAAAfZInZGBU567.png " title= "Ipvs-l-n.png" alt= "Wkiom1bbqwmie2psaaafzinzgbu567.png"/>

8 Open IE Browser on Windows, enter VIP address

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9 Refresh Web page and view 650) this.width=650; "src=" Http://s3.51cto.com/wyfs02/M02/7C/E5/wKiom1bbqrnz2qADAAA5b-M2Ff0639.png "title = "2.PNG" alt= "Wkiom1bbqrnz2qadaaa5b-m2ff0639.png"/>

Through the page we can clearly see the conversion of the homepage, after the page will be refreshed after the Realserver1 and Realserver2 two home page conversion, this is the previous Director defines the Cluster service when the-S RR definition of the polling algorithm used.

10 View the director's Cluster connection status. : 650) this.width=650; "src=" Http://s1.51cto.com/wyfs02/M02/7C/E4/wKioL1bbrAuw6StDAAAiP5xhfg8397.png "title=" Ipvs- L--stats. PNG "alt=" Wkiol1bbrauw6stdaaaip5xhfg8397.png "/>

From the display we can see the response of Realserver1 and Realserver2, incoming messages and outgoing messages, and the number of bytes in and out.

Troubleshooting process: The process of configuration because I forgot to point the Realserver gateway to the dip, resulting in realserver messages can not be sent out, so it has not been shown, so please pay attention to this problem.

Summary: Through the operation of the Lvs-nat model, we can feel the director again in the connection between the client and the Realserver role, the client request message and Realserver reply message all need to pass director, so the cluster scale is large, The director may seem a little tired.

This article is from the "11254923" blog, please be sure to keep this source http://11264923.blog.51cto.com/11254923/1748037

Lvs-nat Model Demo