Class JvmRouteBinderValve

java.lang.Object
org.apache.catalina.util.LifecycleBase
org.apache.catalina.util.LifecycleMBeanBase
org.apache.catalina.valves.ValveBase
org.apache.catalina.ha.session.JvmRouteBinderValve
All Implemented Interfaces:
MBeanRegistration, Contained, ClusterValve, JmxEnabled, Lifecycle, Valve
public class JvmRouteBinderValve extends ValveBase implements ClusterValve
Valve to handle Tomcat jvmRoute takeover using mod_jk module after node failure. After a node crashes, subsequent requests go to other cluster nodes. That incurs a drop in performance. When this Valve is enabled on a backup node and sees a request, which was intended for another (thus failed) node, it will rewrite the cookie jsessionid information to use the route to this backup cluster node, that answered the request. After the response is delivered to the client, all subsequent client requests will go directly to the backup node. The change of sessionid is also sent to all other cluster nodes. After all that, the session stickiness will work directly to the backup node and the traffic will not go back to the failed node after it is restarted!

Add this Valve to your cluster definition at conf/server.xml . 

  <Cluster>
  <Valve className="org.apache.catalina.ha.session.JvmRouteBinderValve" />
  </Cluster>
A Trick:
You can enable this mod_jk turnover mode via JMX before you drop a node to all backup nodes! Set enable true on all JvmRouteBinderValve backups, disable worker at mod_jk and then drop node and restart it! Then enable mod_jk worker and disable JvmRouteBinderValves again. This use case means that only requested sessions are migrated.
Author:
Peter Rossbach

  • Field Details

    • log

      public static final Log log

    • cluster

      protected CatalinaCluster cluster
      the cluster

    • sm

      protected static final StringManager sm
      The string manager for this package.

    • enabled

      protected boolean enabled
      enabled this component

    • numberOfSessions

      protected long numberOfSessions
      number of session that no at this tomcat instance hosted

    • sessionIdAttribute

      protected String sessionIdAttribute

  • Constructor Details

    • JvmRouteBinderValve

      public JvmRouteBinderValve()

  • Method Details

    • getSessionIdAttribute

      public String getSessionIdAttribute()
      set session id attribute to failed node for request.
      Returns:
      Returns the sessionIdAttribute.

    • setSessionIdAttribute

      public void setSessionIdAttribute(String sessionIdAttribute)
      get name of failed request session attribute
      Parameters:
      sessionIdAttribute - The sessionIdAttribute to set.

    • getNumberOfSessions

      public long getNumberOfSessions()
      Returns:
      Returns the number of migrated sessions.

    • getEnabled

      public boolean getEnabled()
      Returns:
      Returns the enabled.

    • setEnabled

      public void setEnabled(boolean enabled)
      Parameters:
      enabled - The enabled to set.

    • invoke

      public void invoke(Request request, Response response) throws IOException, ServletException
      Detect possible the JVMRoute change at cluster backup node..
      Specified by:
      invoke in interface Valve
      Parameters:
      request - tomcat request being processed
      response - tomcat response being processed
      Throws:
      IOException - if an input/output error has occurred
      ServletException - if a servlet error has occurred

    • handlePossibleTurnover

      protected void handlePossibleTurnover(Request request)
      handle possible session turn over.
      Parameters:
      request - current request
      See Also:

    • getLocalJvmRoute

      protected String getLocalJvmRoute(Request request)
      get jvmroute from engine
      Parameters:
      request - current request
      Returns:
      return jvmRoute from ManagerBase or null

    • getManager

      protected Manager getManager(Request request)
      get ClusterManager
      Parameters:
      request - current request
      Returns:
      manager or null

    • getCluster

      public CatalinaCluster getCluster()
      Description copied from interface: ClusterValve
      Returns the cluster the cluster deployer is associated with
      Specified by:
      getCluster in interface ClusterValve
      Returns:
      CatalinaCluster

    • setCluster

      public void setCluster(CatalinaCluster cluster)
      Description copied from interface: ClusterValve
      Associates the cluster deployer with a cluster
      Specified by:
      setCluster in interface ClusterValve
      Parameters:
      cluster - CatalinaCluster

    • handleJvmRoute

      protected void handleJvmRoute(Request request, String sessionId, String localJvmRoute)
      Handle jvmRoute stickiness after tomcat instance failed. After this correction a new Cookie send to client with new jvmRoute and the SessionID change propagate to the other cluster nodes.
      Parameters:
      request - current request
      sessionId - request SessionID from Cookie
      localJvmRoute - local jvmRoute

    • changeSessionID

      protected void changeSessionID(Request request, String sessionId, String newSessionID, Session catalinaSession)
      change session id and send to all cluster nodes
      Parameters:
      request - current request
      sessionId - original session id
      newSessionID - new session id for node migration
      catalinaSession - current session with original session id

    • changeRequestSessionID

      protected void changeRequestSessionID(Request request, String sessionId, String newSessionID)
      Change Request Session id
      Parameters:
      request - current request
      sessionId - original session id
      newSessionID - new session id for node migration

    • changeSessionAuthenticationNote

      protected void changeSessionAuthenticationNote(String sessionId, String newSessionID, Session catalinaSession)
      Change the current session ID that is stored in a session note during authentication. It is part of the CSRF protection.
      Parameters:
      sessionId - The original session ID
      newSessionID - The new session ID for node migration
      catalinaSession - The session object (that will be using the new session ID at the point this method is called)

    • startInternal

      protected void startInternal() throws LifecycleException
      Start this component and implement the requirements of LifecycleBase.startInternal().
      Overrides:
      startInternal in class ValveBase
      Throws:
      LifecycleException - if this component detects a fatal error that prevents this component from being used

    • stopInternal

      protected void stopInternal() throws LifecycleException
      Stop this component and implement the requirements of LifecycleBase.stopInternal().
      Overrides:
      stopInternal in class ValveBase
      Throws:
      LifecycleException - if this component detects a fatal error that prevents this component from being used