Apache Shiro Session Management

Apache Shiro | Simple. Java. Security.
https://shiro.apache.org/session-management.html

ZooKeeper Administrator's Guide
https://zookeeper.apache.org/doc/r3.1.2/zookeeperAdmin.html

Tomcat clustering - A step by step guide | MuleSoft
https://www.mulesoft.com/tcat/tomcat-clustering

Simple Session-Sharing in Tomcat Cluster Using the Session-in-Cookie Pattern Part 1: The Basics – Shine Solutions Group
https://shinesolutions.com/2012/12/18/simple-session-sharing-in-tomcat-cluster-using-the-session-in-cookie-pattern/