Hi cwhsu;
Yeah that’s odd. I tested it out locally and am able to set both individually. Basically the wait_timeout variable is for non-interactive connections, and interactive_timeout is for interactive connections. Would be interesting to see if there is an XtraDB-cluster specific reason for it.
Otherwise I’d try setting wait_timeout directly in /etc/my.cnf or /etc/mysql/my.cnf under the [mysqld] tag to see if it happens to pick it up that way. Still seems likely there is an option file issue going on there somewhere.