Configure Single HTTPServer to Route to Multiple WebSphere Application Servers

Sometime you need configure Single HTTPServer to Route to Multiple WebSphere Application Server, here is a way you can make it:

Scenario:

WAS Server: A and B
HTTP Server: C

Give same HTTPServer Name on Both A and B
1. Create HTTPServer on A, and Generate plugin-cfg.xml and kdb/sth files and propagate them to HTTP Server.
2. Rename them with prefix a-, i.e. a-plugin-cfg.xml, a-plugin-key.kdb, a-plugin-key.sth

Repeat above steps on B, and rename the files with prefix b-

3. Merge the 2 plugin-cfg.xml with pluginCfgMerge.sh, if your HTTPServer and WebSphere Application Server are on different machines, you can merge them on WebSphere Application Server first, then copy to HTTPServer
/opt/IBM/WebSphere/AppServer/bin/pluginCfgMerge.sh a_plugin-cfg.xml b_plugin-cfg.xml plugin-cfg.xml 

4. Verify merged plugin-cfg.xml to ensure the kdb and sth files point correct files
                <Property Name="keyring" Value="/opt/IBM/HTTPServer/Plugins/config/HTTPServer/a-plugin-key.kdb"/>
                <Property Name="stashfile" Value="/opt/IBM/HTTPServer/Plugins/config/HTTPServer/a-plugin-key.sth"/>

5. append below lines to /opt/IBM/WebSphere/conf/httpd.conf
LoadModule was_ap22_module /opt/IBM/WebSphere/Plugins/bin/64bits/mod_was_ap22_http.so
WebSpherePluginConfig  /opt/IBM/HTTPServer/Plugins/config/HTTPServer/plugin-cfg.xml

Apach 2.4
LoadModule was_ap24_module /opt/IBM/WebSphere/Plugins/bin/64bits/mod_was_ap24_http.so
WebSpherePluginConfig  /opt/IBM/WebSphere/Plugins/config/secure9Web/plugin-cfg.xml