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<html lang="en"><head><META http-equiv="Content-Type" content="text/html; charset=UTF-8"><link href="../images/docs-stylesheet.css" rel="stylesheet" type="text/css"><title>Apache Tomcat 8 Configuration Reference (8.5.97) - The ClusterManager object</title><meta name="author" content="Filip Hanik"></head><body><div id="wrapper"><header><div id="header"><div><div><div class="logo noPrint"><a href="https://tomcat.apache.org/"><img alt="Tomcat Home" src="../images/tomcat.png"></a></div><div style="height: 1px;"></div><div class="asfLogo noPrint"><a href="https://www.apache.org/" target="_blank"><img src="../images/asf-logo.svg" alt="The Apache Software Foundation" style="width: 266px; height: 83px;"></a></div><h1>Apache Tomcat 8 Configuration Reference</h1><div class="versionInfo">
Version 8.5.97,
<time datetime="2023-12-07">Dec 7 2023</time></div><div style="height: 1px;"></div><div style="clear: left;"></div></div></div></div></header><div id="middle"><div><div id="mainLeft" class="noprint"><div><nav><div><h2>Links</h2><ul><li><a href="../index.html">Docs Home</a></li><li><a href="index.html">Config Ref. Home</a></li><li><a href="https://cwiki.apache.org/confluence/display/TOMCAT/FAQ">FAQ</a></li><li><a href="#comments_section">User Comments</a></li></ul></div><div><h2>Top Level Elements</h2><ul><li><a href="server.html">Server</a></li><li><a href="service.html">Service</a></li></ul></div><div><h2>Executors</h2><ul><li><a href="executor.html">Executor</a></li></ul></div><div><h2>Connectors</h2><ul><li><a href="http.html">HTTP/1.1</a></li><li><a href="http2.html">HTTP/2</a></li><li><a href="ajp.html">AJP</a></li></ul></div><div><h2>Containers</h2><ul><li><a href="context.html">Context</a></li><li><a href="engine.html">Engine</a></li><li><a href="host.html">Host</a></li><li><a href="cluster.html">Cluster</a></li></ul></div><div><h2>Nested Components</h2><ul><li><a href="cookie-processor.html">CookieProcessor</a></li><li><a href="credentialhandler.html">CredentialHandler</a></li><li><a href="globalresources.html">Global Resources</a></li><li><a href="jar-scanner.html">JarScanner</a></li><li><a href="jar-scan-filter.html">JarScanFilter</a></li><li><a href="listeners.html">Listeners</a></li><li><a href="loader.html">Loader</a></li><li><a href="manager.html">Manager</a></li><li><a href="realm.html">Realm</a></li><li><a href="resources.html">Resources</a></li><li><a href="sessionidgenerator.html">SessionIdGenerator</a></li><li><a href="valve.html">Valve</a></li></ul></div><div><h2>Cluster Elements</h2><ul><li><a href="cluster.html">Cluster</a></li><li><a href="cluster-manager.html">Manager</a></li><li><a href="cluster-channel.html">Channel</a></li><li><a href="cluster-membership.html">Channel/Membership</a></li><li><a href="cluster-sender.html">Channel/Sender</a></li><li><a href="cluster-receiver.html">Channel/Receiver</a></li><li><a href="cluster-interceptor.html">Channel/Interceptor</a></li><li><a href="cluster-valve.html">Valve</a></li><li><a href="cluster-deployer.html">Deployer</a></li><li><a href="cluster-listener.html">ClusterListener</a></li></ul></div><div><h2>web.xml</h2><ul><li><a href="filter.html">Filter</a></li></ul></div><div><h2>Other</h2><ul><li><a href="systemprops.html">System properties</a></li><li><a href="jaspic.html">JASPIC</a></li></ul></div></nav></div></div><div id="mainRight"><div id="content"><h2>The ClusterManager object</h2><h3 id="Table_of_Contents">Table of Contents</h3><div class="text">
<ul><li><a href="#Introduction">Introduction</a></li><li><a href="#The_<Manager>">The <Manager></a></li><li><a href="#Attributes">Attributes</a><ol><li><a href="#Common_Attributes">Common Attributes</a></li><li><a href="#org.apache.catalina.ha.session.DeltaManager_Attributes">org.apache.catalina.ha.session.DeltaManager Attributes</a></li><li><a href="#org.apache.catalina.ha.session.BackupManager_Attributes">org.apache.catalina.ha.session.BackupManager Attributes</a></li></ol></li><li><a href="#Nested_Components">Nested Components</a></li></ul>
</div><h3 id="Introduction">Introduction</h3><div class="text">
<p>A cluster manager is an extension to Tomcat's session manager interface,
<code>org.apache.catalina.Manager</code>.
A cluster manager must implement the
<code>org.apache.catalina.ha.ClusterManager</code> and is solely responsible
for how the session is replicated.<br>
There are currently two different managers, the
<code>org.apache.catalina.ha.session.DeltaManager</code> replicates deltas of
session data to all members in the cluster. This implementation is proven and
works very well, but has a limitation as it requires the cluster members to be
homogeneous, all nodes must deploy the same applications and be exact
replicas. The <code>org.apache.catalina.ha.session.BackupManager</code> also
replicates deltas but only to one backup node. The location of the backup node
is known to all nodes in the cluster. It also supports heterogeneous
deployments, so the manager knows at what locations the web application is
deployed.</p>
</div><h3 id="The_<Manager>">The <Manager></h3><div class="text">
<p>The <code><Manager></code> element defined inside the
<code><Cluster></code> element is the template defined for all web
applications that are marked <code><distributable/></code> in their
<code>web.xml</code> file. However, you can still override the manager
implementation on a per web application basis, by putting the
<code><Manager></code> inside the <code><Context></code> element
either in the <code><a href="context.html">context.xml</a></code> file or the
<code><a href="index.html">server.xml</a></code> file.</p>
</div><h3 id="Attributes">Attributes</h3><div class="text">
<div class="subsection"><h4 id="Common_Attributes">Common Attributes</h4><div class="text">
<table class="defaultTable"><tr><th style="width: 15%;">
Attribute
</th><th style="width: 85%;">
Description
</th></tr><tr><td><strong><code class="attributeName">className</code></strong></td><td>
</td></tr><tr><td><code class="attributeName">name</code></td><td>
<b>The name of this cluster manager, the name is used to identify a
session manager on a node. The name might get modified by the
<code>Cluster</code> element to make it unique in the container.</b>
</td></tr><tr><td><code class="attributeName">notifyListenersOnReplication</code></td><td>
Set to <code>true</code> if you wish to have session listeners notified
when session attributes are being replicated or removed across Tomcat
nodes in the cluster.
</td></tr><tr><td><code class="attributeName">processExpiresFrequency</code></td><td>
<p>Frequency of the session expiration, and related manager operations.
Manager operations will be done once for the specified amount of
backgroundProcess calls (i.e., the lower the amount, the more often the
checks will occur). The minimum value is 1, and the default value is 6.
</p>
</td></tr><tr><td><code class="attributeName">secureRandomClass</code></td><td>
<p>Name of the Java class that extends
<code>java.security.SecureRandom</code> to use to generate session IDs.
If not specified, the default value is
<code>java.security.SecureRandom</code>.</p>
</td></tr><tr><td><code class="attributeName">secureRandomProvider</code></td><td>
<p>Name of the provider to use to create the
<code>java.security.SecureRandom</code> instances that generate session
IDs. If an invalid algorithm and/or provider is specified, the Manager
will use the platform default provider and the default algorithm. If not
specified, the platform default provider will be used.</p>
</td></tr><tr><td><code class="attributeName">secureRandomAlgorithm</code></td><td>
<p>Name of the algorithm to use to create the
<code>java.security.SecureRandom</code> instances that generate session
IDs. If an invalid algorithm and/or provider is specified, the Manager
will use the platform default provider and the default algorithm. If not
specified, the default algorithm of SHA1PRNG will be used. If the
default algorithm is not supported, the platform default will be used.
To specify that the platform default should be used, do not set the
secureRandomProvider attribute and set this attribute to the empty
string.</p>
</td></tr><tr><td><code class="attributeName">recordAllActions</code></td><td>
<p>Flag whether send all actions for session across Tomcat cluster
nodes. If set to false, if already done something to the same attribute,
make sure don't send multiple actions across Tomcat cluster nodes.
In that case, sends only the actions that have been added at last.
Default is <code>false</code>.</p>
</td></tr></table>
</div></div>
<div class="subsection"><h4 id="org.apache.catalina.ha.session.DeltaManager_Attributes">org.apache.catalina.ha.session.DeltaManager Attributes</h4><div class="text">
<table class="defaultTable"><tr><th style="width: 15%;">
Attribute
</th><th style="width: 85%;">
Description
</th></tr><tr><td><code class="attributeName">expireSessionsOnShutdown</code></td><td>
When a web application is being shutdown, Tomcat issues an expire call
to each session to notify all the listeners. If you wish for all
sessions to expire on all nodes when a shutdown occurs on one node, set
this value to <code>true</code>.
Default value is <code>false</code>.
</td></tr><tr><td><code class="attributeName">maxActiveSessions</code></td><td>
The maximum number of active sessions that will be created by this
Manager, or -1 (the default) for no limit. For this manager, all
sessions are counted as active sessions irrespective if whether or not
the current node is the primary node for the session.
</td></tr><tr><td><code class="attributeName">notifySessionListenersOnReplication</code></td><td>
Set to <code>true</code> if you wish to have session listeners notified
when sessions are created and expired across Tomcat nodes in the
cluster.
</td></tr><tr><td><code class="attributeName">notifyContainerListenersOnReplication</code></td><td>
Set to <code>true</code> if you wish to have container listeners notified
across Tomcat nodes in the cluster.
</td></tr><tr><td><code class="attributeName">persistAuthenticationNotes</code></td><td>
<p>Should authentication notes (used during FORM authentication) be
included when sessions are replicated? If <code>true</code>, the
session's authentication notes (used during FORM authentication) are
replicated so that an in progress FORM authentication can continue if
failover occurs during FORM authentication. If not specified, the
default value of <code>false</code> will be used.</p>
<p>Please note that all nodes must be upgraded to at least 8.5.83 (the
version where this feature was introduced) before this feature is
enabled else session replication may fail.</p>
<p>This attribute has been removed for Tomcat 10.1.x onwards which
always replicates FORM authenticaton notes.</p>
</td></tr><tr><td><code class="attributeName">stateTransferTimeout</code></td><td>
The time in seconds to wait for a session state transfer to complete
from another node when a node is starting up.
Default value is <code>60</code> seconds.
</td></tr><tr><td><code class="attributeName">sendAllSessions</code></td><td>
Flag whether send sessions as split blocks.
If set to <code>true</code>, send all sessions as one big block.
If set to <code>false</code>, send sessions as split blocks.
Default value is <code>true</code>.
</td></tr><tr><td><code class="attributeName">sendAllSessionsSize</code></td><td>
The number of sessions in a session block message. This value is
effective only when <code>sendAllSessions</code> is <code>false</code>.
Default is <code>1000</code>.
</td></tr><tr><td><code class="attributeName">sendAllSessionsWaitTime</code></td><td>
Wait time between sending of session block messages. This value is
effective only when <code>sendAllSessions</code> is <code>false</code>.
Default is <code>2000</code> milliseconds.
</td></tr><tr><td><code class="attributeName">sessionAttributeNameFilter</code></td><td>
<p>A regular expression used to filter which session attributes will be
replicated. An attribute will only be replicated if its name matches
this pattern. If the pattern is zero length or <code>null</code>, all
attributes are eligible for replication. The pattern is anchored so the
session attribute name must fully match the pattern. As an example, the
value <code>(userName|sessionHistory)</code> will only replicate the
two session attributes named <code>userName</code> and
<code>sessionHistory</code>. If not specified, the default value of
<code>null</code> will be used.</p>
</td></tr><tr><td><code class="attributeName">sessionAttributeValueClassNameFilter</code></td><td>
<p>A regular expression used to filter which session attributes will be
replicated. An attribute will only be replicated if the implementation
class name of the value matches this pattern. If the pattern is zero
length or <code>null</code>, all attributes are eligible for
replication. The pattern is anchored so the fully qualified class name
must fully match the pattern. If not specified, the default value of
<code>null</code> will be used unless a <code>SecurityManager</code> is
enabled in which case the default will be
<code>java\\.lang\\.(?:Boolean|Integer|Long|Number|String)</code>.</p>
</td></tr><tr><td><code class="attributeName">stateTimestampDrop</code></td><td>
When this node sends a <code>GET_ALL_SESSIONS</code> message to other
node, all session messages that are received as a response are queued.
If this attribute is set to <code>true</code>, the received session
messages (except any <code>GET_ALL_SESSIONS</code> sent by other nodes)
are filtered by their timestamp. A message is dropped if it is not a
<code>GET_ALL_SESSIONS</code> message and its timestamp is earlier than
the timestamp of our <code>GET_ALL_SESSIONS</code> message.
If set to <code>false</code>, all queued session messages are handled.
Default is <code>true</code>.
</td></tr><tr><td><code class="attributeName">warnOnSessionAttributeFilterFailure</code></td><td>
<p>If <strong>sessionAttributeNameFilter</strong> or
<strong>sessionAttributeValueClassNameFilter</strong> blocks an
attribute, should this be logged at <code>WARN</code> level? If
<code>WARN</code> level logging is disabled then it will be logged at
<code>DEBUG</code>. The default value of this attribute is
<code>false</code> unless a <code>SecurityManager</code> is enabled in
which case the default will be <code>true</code>.</p>
</td></tr></table>
</div></div>
<div class="subsection"><h4 id="org.apache.catalina.ha.session.BackupManager_Attributes">org.apache.catalina.ha.session.BackupManager Attributes</h4><div class="text">
<table class="defaultTable"><tr><th style="width: 15%;">
Attribute
</th><th style="width: 85%;">
Description
</th></tr><tr><td><code class="attributeName">mapSendOptions</code></td><td>
The backup manager uses a replicated map, this map is sending and
receiving messages. You can setup the flag for how this map is sending
messages, the default value is <code>6</code>(synchronous).<br>
Note that if you use asynchronous messaging it is possible for update
messages for a session to be processed by the receiving node in a
different order to the order in which they were sent.
</td></tr><tr><td><code class="attributeName">maxActiveSessions</code></td><td>
The maximum number of active sessions that will be created by this
Manager, or -1 (the default) for no limit. For this manager, only
sessions where the current node is the primary node for the session are
considered active sessions.
</td></tr><tr><td><code class="attributeName">persistAuthenticationNotes</code></td><td>
<p>Should authentication notes (used during FORM authentication) be
included when sessions are replicated? If <code>true</code>, the
session's authentication notes (used during FORM authentication) are
replicated so that an in progress FORM authentication can continue if
failover occurs during FORM authentication. If not specified, the
default value of <code>false</code> will be used.</p>
<p>Please note that all nodes must be upgraded to at least 8.5.83 (the
version where this feature was introduced) before this feature is
enabled else session replication may fail.</p>
<p>This attribute has been removed for Tomcat 10.1.x onwards which
always replicates FORM authenticaton notes.</p>
</td></tr><tr><td><code class="attributeName">rpcTimeout</code></td><td>
Timeout for RPC message used for broadcast and transfer state from
another map.
Default value is <code>15000</code> milliseconds.
</td></tr><tr><td><code class="attributeName">sessionAttributeNameFilter</code></td><td>
<p>A regular expression used to filter which session attributes will be
replicated. An attribute will only be replicated if its name matches
this pattern. If the pattern is zero length or <code>null</code>, all
attributes are eligible for replication. The pattern is anchored so the
session attribute name must fully match the pattern. As an example, the
value <code>(userName|sessionHistory)</code> will only replicate the
two session attributes named <code>userName</code> and
<code>sessionHistory</code>. If not specified, the default value of
<code>null</code> will be used.</p>
</td></tr><tr><td><code class="attributeName">sessionAttributeValueClassNameFilter</code></td><td>
<p>A regular expression used to filter which session attributes will be
replicated. An attribute will only be replicated if the implementation
class name of the value matches this pattern. If the pattern is zero
length or <code>null</code>, all attributes are eligible for
replication. The pattern is anchored so the fully qualified class name
must fully match the pattern. If not specified, the default value of
<code>null</code> will be used unless a <code>SecurityManager</code> is
enabled in which case the default will be
<code>java\\.lang\\.(?:Boolean|Integer|Long|Number|String)</code>.</p>
</td></tr><tr><td><code class="attributeName">terminateOnStartFailure</code></td><td>
Set to true if you wish to terminate replication map when replication
map fails to start. If replication map is terminated, associated context
will fail to start. If you set this attribute to false, replication map
does not end. It will try to join the map membership in the heartbeat.
Default value is <code>false</code> .
</td></tr><tr><td><code class="attributeName">warnOnSessionAttributeFilterFailure</code></td><td>
<p>If <strong>sessionAttributeNameFilter</strong> or
<strong>sessionAttributeValueClassNameFilter</strong> blocks an
attribute, should this be logged at <code>WARN</code> level? If
<code>WARN</code> level logging is disabled then it will be logged at
<code>DEBUG</code>. The default value of this attribute is
<code>false</code> unless a <code>SecurityManager</code> is enabled in
which case the default will be <code>true</code>.</p>
</td></tr><tr><td><code class="attributeName">accessTimeout</code></td><td>
The timeout for a ping message. If a remote map does not respond within
this timeout period, its regarded as disappeared.
Default value is <code>5000</code> milliseconds.
</td></tr></table>
</div></div>
</div><h3 id="Nested_Components">Nested Components</h3><div class="text">
<h3>All Manager Implementations</h3>
<p>All Manager implementations allow nesting of a
<strong><SessionIdGenerator></strong> element. It defines
the behavior of session id generation. All implementations
of the <a href="sessionidgenerator.html">SessionIdGenerator</a> allow the
following attributes:
</p>
<table class="defaultTable"><tr><th style="width: 15%;">
Attribute
</th><th style="width: 85%;">
Description
</th></tr><tr><td><code class="attributeName">sessionIdLength</code></td><td>
<p>The length of the session ID may be changed with the
<strong>sessionIdLength</strong> attribute.
</p>
</td></tr></table>
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