# Package org.apache.catalina.ha

package org.apache.catalina.ha

This package contains code for Clustering, the base class of a Cluster is `org.apache.catalina.Cluster` implementations of this class is done when implementing a new Cluster protocol

- Related Packages
  Package
  Description
  org.apache.catalina
  org.apache.catalina.ha.authenticator
  org.apache.catalina.ha.backend
  org.apache.catalina.ha.context
  org.apache.catalina.ha.deploy
  org.apache.catalina.ha.session
  org.apache.catalina.ha.tcp
- Class
  Description
  CatalinaCluster
  A CatalinaCluster interface allows to plug in and out the different cluster implementations
  ClusterDeployer
  A ClusterDeployer interface allows to plug in and out the different deployment implementations
  ClusterListener
  Receive SessionID cluster change from other backup node after primary session node is failed.
  ClusterManager
  The common interface used by all cluster manager.
  ClusterMessage
  Interface for messages exchanged between cluster nodes.
  ClusterMessageBase
  Base implementation of `ClusterMessage` providing common fields and methods for cluster messages.
  ClusterRuleSet
  RuleSet for processing the contents of a Cluster definition element.
  ClusterSession
  Interface for a cluster-aware session that extends both `Session` and `HttpSession`.
  ClusterValve
  Cluster valves are a simple extension to the Tomcat valve architecture with a small addition of being able to reference the cluster component in the container it sits in.