When creating a cluster with static membership the number of participating cluster-nodes sometimes is not static. Therefore it should be possible to add/remove members in such a static-membership cluster without restarting the other already running tomcat instances. As far as I cloud tell there is currently no possibility to do that. This would be suited as a jmx feature. See also the mailing-list discussion http://mail-archives.apache.org/mod_mbox/tomcat-users/201504.mbox/%3C552FC04E.1030605%40gmail.com%3E
With Tomcat 7 reaching EOL, move the remaining open enhancement requests to Tomcat 8.