Use Haproxy Keepalived for dual-active load balancing installation and configuration

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Environment Preparation

1. Start four virtual machines (centos is used as an example here), the ip is:

192.168.130

192.168.132

192.168.128

192.168.129

2. Install haproxy

Open the external network access rights for the corresponding ports 130 and 132 of these two machines

Install haproxy on machines 130 and 132 respectively:

After both machines are installed, perform file configuration and modify the configuration file on 132:

Copy the configuration file to the same directory on the 130 server and perform the following operations on the 130 server:

The haproxy installation and configuration of the two servers are complete.

3. Install keepalived on 132 and 130 respectively:

First check to install openssl-devel

Create a keepalived installation directory and download and install it:

After both machines are installed, configure keepalived (132 machines):

Create a detection file

Copy the configuration and detection files to another server and perform the following operations on 130:

Here keepalived is installed.

4. Install the tomcat service environment

Copy two tomcats in 128, one with port 8080 and one with port 8081:

a. Modify the tomcat port, which is too low. Execute the operation.

b. Modify the tomcat page in tomcat port 8080 to facilitate testing and verification:

• Import js in head: <script type="text/javascript" src="test.js"></script>
• Add server description html under body: <h1>web-128:8080</h1><h1 id="js_h">js location</h1> (indicates that this is the service page of port 8080 of host 128)
• Create a new test.js in the same directory as index.jsp: window.onload = function(){document.getElementById("js_h").innerHTML='js-128:8080′;}

The js file will modify the "js location" content, indicating that this js file comes from the 8080 port service of the 128 host.

c. Make similar changes in tomcat port 8081:

• Import js in head: <script type="text/javascript" src="test.js"></script>
• Add server description html under body: <h1>web-128:8081</h1><h1 id="js_h">js location</h1>
• test.js: window.onload = function() {document.getElementById("js_h").innerHTML='js-128:8081';}

Similarly, copy two tomcats on the 129 server, one with port 8080 and the other with port 8081. When modifying the tomcat file, just change ip 128 to 129.

Now the environment is installed.

Run 4 tomcats

Run haproxy: service haproxy start

Run keepalived:

Open the page to view the haproxy monitoring page: http://192.168.230.132/haproxy, http://192.168.230.130/haproxy

Through monitoring, you can see the number of visits and other messages

Refresh the page multiple times by visiting http://192.168.230.200 or http://192.168.230.201:

By observing the changes in the source of the js file and the page, we can see that the js file comes from the server with port 8080 of 128 and 129, and the page comes from the server with port 8081 of 128 and 129. Describes the different haproxy service rules used for page and static file loads

Visit http://192.168.230.200, http://192.168.230.201. By monitoring the data changes on the page, we can find that 200 is forwarded by the 132 server, and access 201 is forwarded by 130

In actual scenarios, when accessing dynamic resources, the 200 address is used, and when accessing static resources, the 201 address is used. By shutting down tomcat or haproxy, you can see the server switching. This achieves dual-master backup, ensuring high availability while also improving server utilization.

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