CATALINA_HOME is needed for any Tomcat build to function properly. Tomcat uses this variable to find the location of internal classes and libraries.
CATALINA_BASE is used by Tomcat to find the location of the configuration-specific files and directories,such as configuration files, the scratch directory in which JSPs are compiled, log files,and the various Web applications. In case CATALINA_BASE is not set, it defaults to the value of CATALINA_HOME .