JvmRouteBinderValve (Apache Tomcat 7.0.67 API Documentation)

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:

javax.management.MBeanRegistration, Contained, ClusterValve, 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!
For this valve to function correctly, so that all nodes of the cluster receive the sessionid change notifications that it generates, the following ClusterListener MUST be configured at all nodes of the cluster: JvmRouteSessionIDBinderListener since Tomcat 5.5.10, and both JvmRouteSessionIDBinderListener and JvmRouteSessionIDBinderLifecycleListener for earlier versions of Tomcat.
Add this Valve to your host definition at conf/server.xml . Since 5.5.10 as direct cluster valve:
```
  <Cluster>
  <Valve className="org.apache.catalina.ha.session.JvmRouteBinderValve" />  
  </Cluster>
 
```
Before 5.5.10 as Host element:
```
  <Host>
  <Valve className="org.apache.catalina.ha.session.JvmRouteBinderValve" />  
  </Host>
 
```
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 Summary

Fields
Modifier and Type	Field and Description
`protected CatalinaCluster`	`cluster` the cluster
`protected boolean`	`enabled` enabled this component
`protected static java.lang.String`	`info` The descriptive information about this implementation.
`static Log`	`log`
`protected long`	`numberOfSessions` number of session that no at this tomcat instanz hosted
`protected java.lang.String`	`sessionIdAttribute`
`protected static StringManager`	`sm` The string manager for this package.

Fields inherited from class org.apache.catalina.valves.ValveBase
asyncSupported, container, containerLog, next

Fields inherited from class org.apache.catalina.util.LifecycleMBeanBase
mserver

Fields inherited from interface org.apache.catalina.Lifecycle
AFTER_DESTROY_EVENT, AFTER_INIT_EVENT, AFTER_START_EVENT, AFTER_STOP_EVENT, BEFORE_DESTROY_EVENT, BEFORE_INIT_EVENT, BEFORE_START_EVENT, BEFORE_STOP_EVENT, CONFIGURE_START_EVENT, CONFIGURE_STOP_EVENT, PERIODIC_EVENT, START_EVENT, STOP_EVENT

Constructor Summary

Constructors
Constructor and Description

JvmRouteBinderValve()

Constructors
Constructor and Description
`JvmRouteBinderValve()`

Method Summary

Methods
Modifier and Type	Method and Description
`protected void`	`changeRequestSessionID(Request request, java.lang.String sessionId, java.lang.String newSessionID)` Change Request Session id
`protected void`	`changeSessionID(Request request, java.lang.String sessionId, java.lang.String newSessionID, Session catalinaSession)` change session id and send to all cluster nodes
`CatalinaCluster`	`getCluster()` Returns the cluster the cluster deployer is associated with
`boolean`	`getEnabled()`
`java.lang.String`	`getInfo()` Return descriptive information about this implementation.
`protected java.lang.String`	`getLocalJvmRoute(Request request)` get jvmroute from engine
`protected Manager`	`getManager(Request request)` get ClusterManager
`long`	`getNumberOfSessions()`
`java.lang.String`	`getSessionIdAttribute()` set session id attribute to failed node for request.
`protected void`	`handleJvmRoute(Request request, java.lang.String sessionId, java.lang.String localJvmRoute)` Handle jvmRoute stickiness after tomcat instance failed.
`protected void`	`handlePossibleTurnover(Request request)` handle possible session turn over.
`void`	`invoke(Request request, Response response)` Detect possible the JVMRoute change at cluster backup node..
`protected void`	`sendSessionIDClusterBackup(Request request, java.lang.String sessionId, java.lang.String newSessionID)` Send the changed Sessionid to all clusternodes.
`void`	`setCluster(CatalinaCluster cluster)` Associates the cluster deployer with a cluster
`void`	`setEnabled(boolean enabled)`
`void`	`setSessionIdAttribute(java.lang.String sessionIdAttribute)` get name of failed request session attribute
`protected void`	`startInternal()` Start this component and implement the requirements of `LifecycleBase.startInternal()`.
`protected void`	`stopInternal()` Stop this component and implement the requirements of `LifecycleBase.stopInternal()`.

Methods inherited from class org.apache.catalina.valves.ValveBase
backgroundProcess, event, getContainer, getDomainInternal, getNext, getObjectNameKeyProperties, initInternal, isAsyncSupported, setAsyncSupported, setContainer, setNext, toString

Methods inherited from class org.apache.catalina.util.LifecycleMBeanBase
destroyInternal, getDomain, getObjectName, postDeregister, postRegister, preDeregister, preRegister, register, setDomain, unregister

Methods inherited from class org.apache.catalina.util.LifecycleBase
addLifecycleListener, destroy, findLifecycleListeners, fireLifecycleEvent, getState, getStateName, init, removeLifecycleListener, setState, setState, start, stop

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface org.apache.catalina.Valve
backgroundProcess, event, getNext, isAsyncSupported, setNext

- Field Detail
  - log
```
public static final Log log
```
  - info
```
protected static final java.lang.String info
```
    The descriptive information about this implementation.
    
    See Also:
    Constant Field Values
  - 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 instanz hosted
  - sessionIdAttribute
```
protected java.lang.String sessionIdAttribute
```
- Constructor Detail
  - JvmRouteBinderValve
```
public JvmRouteBinderValve()
```
- Method Detail
  - getInfo
```
public java.lang.String getInfo()
```
    Return descriptive information about this implementation.
    
    Specified by:
    
    getInfo in interface Valve
    
    Overrides:
    
    getInfo in class ValveBase
  - getSessionIdAttribute
```
public java.lang.String getSessionIdAttribute()
```
    set session id attribute to failed node for request.
    
    Returns:
    Returns the sessionIdAttribute.
  - setSessionIdAttribute
```
public void setSessionIdAttribute(java.lang.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 java.io.IOException,
                   ServletException
```
    Detect possible the JVMRoute change at cluster backup node..
    
    Specified by:
    
    invoke in interface Valve
    
    Specified by:
    
    invoke in class ValveBase
    
    Parameters:
    request - tomcat request being processed
    response - tomcat response being processed
    
    Throws:
    
    java.io.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:
    handleJvmRoute(Request, String, String)
  - getLocalJvmRoute
```
protected java.lang.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:
    Returns the cluster.
  - 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 - The cluster to set.
  - handleJvmRoute
```
protected void handleJvmRoute(Request request,
                  java.lang.String sessionId,
                  java.lang.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,
                   java.lang.String sessionId,
                   java.lang.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,
                          java.lang.String sessionId,
                          java.lang.String newSessionID)
```
    Change Request Session id
    
    Parameters:
    request - current request
    sessionId - original session id
    newSessionID - new session id for node migration
  - sendSessionIDClusterBackup
```
protected void sendSessionIDClusterBackup(Request request,
                              java.lang.String sessionId,
                              java.lang.String newSessionID)
```
    Send the changed Sessionid to all clusternodes.
    
    Parameters:
    sessionId - current failed sessionid
    newSessionID - new session id, bind to the new cluster node
    See Also:
    JvmRouteSessionIDBinderListener.messageReceived( org.apache.catalina.ha.ClusterMessage)
  - 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

Class JvmRouteBinderValve

Field Summary

Fields inherited from class org.apache.catalina.valves.ValveBase

Fields inherited from class org.apache.catalina.util.LifecycleMBeanBase

Fields inherited from interface org.apache.catalina.Lifecycle

Constructor Summary

Method Summary

Methods inherited from class org.apache.catalina.valves.ValveBase

Methods inherited from class org.apache.catalina.util.LifecycleMBeanBase

Methods inherited from class org.apache.catalina.util.LifecycleBase

Methods inherited from class java.lang.Object

Methods inherited from interface org.apache.catalina.Valve

Field Detail

log

info

cluster

sm

enabled

numberOfSessions

sessionIdAttribute

Constructor Detail

JvmRouteBinderValve

Method Detail

getInfo

getSessionIdAttribute

setSessionIdAttribute

getNumberOfSessions

getEnabled

setEnabled

invoke

handlePossibleTurnover

getLocalJvmRoute

getManager

getCluster

setCluster

handleJvmRoute

changeSessionID

changeRequestSessionID

sendSessionIDClusterBackup

startInternal

stopInternal