setting up AJP secret between Apache and Tomcat

mod_proxy_ajp didn't support the secret option before Apache 2.5.

Please refer:

  • v2.4 document: https://httpd.apache.org/docs/2.4/mod/mod_proxy_ajp.html

  • v2.5 document: https://httpd.apache.org/docs/trunk/mod/mod_proxy_ajp.html