# Apache Tomcat 7

Version 7.0.30, Sep 2 2012

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# Monitoring and Managing Tomcat

Table of Contents

> - Introduction
> - Enabling JMX Remote
> - Manage Tomcat with JMX remote Ant Tasks
> - JMXAccessorOpenTask - JMX open connection task
> - JMXAccessorGetTask: get attribute value Ant task
> - JMXAccessorSetTask: set attribute value Ant task
> - JMXAccessorInvokeTask: invoke MBean operation Ant task
> - JMXAccessorQueryTask: query MBean Ant task
> - JMXAccessorCreateTask: remote create MBean Ant task
> - JMXAccessorUnregisterTask: remote unregister MBean Ant task
> - JMXAccessorCondition: express condition
> - JMXAccessorEqualsCondition: equals MBean Ant condition
> - Using the JMXProxyServlet

Introduction

> Monitoring is a key aspect of system administration. Looking inside a running server, obtaining some statistics or reconfiguring some aspects of an application are all daily administration tasks.

Enabling JMX Remote

> The Sun website includes the list of options and how to configure JMX Remote on Java 5: http://docs.oracle.com/javase/6/docs/technotes/guides/management/agent.html.

> The following is a quick configuration guide for Java 6:

> Add the following parameters to your Tomcat startup script:

>         set CATALINA_OPTS=-Dcom.sun.management.jmxremote \
>         -Dcom.sun.management.jmxremote.port=%my.jmx.port% \
>         -Dcom.sun.management.jmxremote.ssl=false \
>         -Dcom.sun.management.jmxremote.authenticate=false

> 1. If you require authorization, add and change this :

>            -Dcom.sun.management.jmxremote.authenticate=true \
>            -Dcom.sun.management.jmxremote.password.file=../conf/jmxremote.password \
>            -Dcom.sun.management.jmxremote.access.file=../conf/jmxremote.access \

> 2. edit the access authorization file $CATALINA_BASE/conf/jmxremote.access :

>        monitorRole readonly
>        controlRole readwrite

> 3. edit the password file $CATALINA_BASE/conf/jmxremote.password :

>        monitorRole tomcat
>        controlRole tomcat

>    Tip: The password file should be read-only and only accessible by the operating system user Tomcat is running as.
> Note:The JSR 160 JMX-Adaptor opens a second data channel on a random port. That is a problem when you have a local firewall installed.

Manage Tomcat with JMX remote Ant Tasks

> To simplify JMX usage with Ant 1.6.x, a set of tasks is provided that may be used with antlib.

> antlib: Copy your catalina-ant.jar from $CATALINA_HOME/lib to $ANT_HOME/lib.

> The following example shows the JMX Accessor usage:

>     <project name="Catalina Ant JMX"
>             xmlns:jmx="antlib:org.apache.catalina.ant.jmx"
>             default="state"
>             basedir=".">
>         <property name="jmx.server.name" value="localhost" />
>         <property name="jmx.server.port" value="9012" />
>         <property name="cluster.server.address" value="192.168.1.75" />
>         <property name="cluster.server.port" value="9025" />

>         <target name="state" description="Show JMX Cluster state">
>             <jmx:open
>                 host="${jmx.server.name}"
>                 port="${jmx.server.port}"
>                 username="controlRole"
>                 password="tomcat"/>
>             <jmx:get
>                 name="Catalina:type=IDataSender,host=localhost,senderAddress=${cluster.server.address},senderPort=${cluster.server.port}"
>                 attribute="connected"
>                 resultproperty="IDataSender.backup.connected"
>                 echo="false"
>             />
>            <jmx:get
>                 name="Catalina:type=ClusterSender,host=localhost"
>                 attribute="senderObjectNames"
>                 resultproperty="senderObjectNames"
>                 echo="false"
>             />
>             <!-- get current maxActiveSession from ClusterTest application
>                  echo it to Ant output and store at
>                  property <em>clustertest.maxActiveSessions.orginal</em>
>             -->
>            <jmx:get
>                 name="Catalina:type=Manager,context=/ClusterTest,host=localhost"
>                 attribute="maxActiveSessions"
>                 resultproperty="clustertest.maxActiveSessions.orginal"
>                 echo="true"
>             />
>             <!-- set maxActiveSession to 100
>             -->
>             <jmx:set
>                 name="Catalina:type=Manager,context=/ClusterTest,host=localhost"
>                 attribute="maxActiveSessions"
>                 value="100"
>                 type="int"
>             />
>             <!-- get all sessions and split result as delimiter <em>SPACE</em> for easy
>                  access all session ids directly with Ant property sessions.[0..n].
>             -->
>             <jmx:invoke
>                 name="Catalina:type=Manager,context=/ClusterTest,host=localhost"
>                 operation="listSessionIds"
>                 resultproperty="sessions"
>                 echo="false"
>                 delimiter=" "
>             />
>             <!-- Access session attribute <em>Hello</em> from first session.
>             -->
>             <jmx:invoke
>                 name="Catalina:type=Manager,context=/ClusterTest,host=localhost"
>                 operation="getSessionAttribute"
>                 resultproperty="Hello"
>                 echo="false"
>             >
>               <arg value="${sessions.0}"/>
>               <arg value="Hello"/>
>             </jmx:invoke>
>             <!-- Query for all application manager.of the server from all hosts
>                  and bind all attributes from all found manager MBeans.
>             -->
>             <jmx:query
>                 name="Catalina:type=Manager,*"
>                 resultproperty="manager"
>                 echo="true"
>                 attributebinding="true"
>             />
>             <!-- echo the create properties -->
>             <echo>
>                senderObjectNames: ${senderObjectNames.0}
>                IDataSender.backup.connected: ${IDataSender.backup.connected}
>                session: ${sessions.0}
>                manager.length: ${manager.length}
>                manager.0.name: ${manager.0.name}
>                manager.1.name: ${manager.1.name}
>                hello: ${Hello}
>                manager.ClusterTest.0.name: ${manager.ClusterTest.0.name}
>                manager.ClusterTest.0.activeSessions: ${manager.ClusterTest.0.activeSessions}
>                manager.ClusterTest.0.counterSend_EVT_SESSION_EXPIRED: ${manager.ClusterTest.0.counterSend_EVT_SESSION_EXPIRED}
>                manager.ClusterTest.0.counterSend_EVT_GET_ALL_SESSIONS: ${manager.ClusterTest.0.counterSend_EVT_GET_ALL_SESSIONS}
>             </echo>

>         </target>

>     </project>

> import: Import the JMX Accessor Project with <import file="${CATALINA.HOME}/bin/catalina-tasks.xml" /> and reference the tasks with jmxOpen, jmxSet, jmxGet, jmxQuery, jmxInvoke, jmxEquals and jmxCondition.

JMXAccessorOpenTask - JMX open connection task

> List of Attributes

> Attribute | Description | Default value
> --- | --- | ---
> url | Set JMX connection URL - service:jmx:rmi:///jndi/rmi://localhost:8050/jmxrmi |
> host | Set the host, shortcut the very long URL syntax. | `localhost`
> port | Set the remote connection port | `8050`
> username | remote JMX connection user name. |
> password | remote JMX connection password. |
> ref | Name of the internal connection reference. With this attribute you can configure more the one connection inside the same Ant project. | `jmx.server`
> echo | Echo the command usage (for access analysis or debugging) | `false`
> if | Only execute if a property of the given name exists in the current project. |
> unless | Only execute if a property of the given name not exists in the current project. |

> Example to open a new JMX connection

>         <jmx:open
>                 host="${jmx.server.name}"
>                 port="${jmx.server.port}"
>         />

> Example to open a JMX connection from URL, with authorization and store at other reference

>         <jmx:open
>                 url="service:jmx:rmi:///jndi/rmi://localhost:9024/jmxrmi"
>                 ref="jmx.server.9024"
>                 username="controlRole"
>                 password="tomcat"
>         />

> Example to open a JMX connection from URL, with authorization and store at other reference, but only when property jmx.if exists and jmx.unless not exists

>         <jmx:open
>                 url="service:jmx:rmi:///jndi/rmi://localhost:9024/jmxrmi"
>                 ref="jmx.server.9024"
>                 username="controlRole"
>                 password="tomcat"
>                 if="jmx.if"
>                 unless="jmx.unless"
>         />

> Note: All properties from jmxOpen task also exists at all other tasks and conditions.

JMXAccessorGetTask: get attribute value Ant task

> List of Attributes

> Attribute | Description | Default value
> --- | --- | ---
> name | Full qualified JMX ObjectName -- Catalina:type=Server |
> attribute | Existing MBean attribute (see Tomcat MBean description above) |
> ref | JMX Connection reference | `jmx.server`
> echo | Echo command usage (access and result) | `false`
> resultproperty | Save result at this project property |
> delimiter | Split result with delimiter (java.util.StringTokenizier) and use resultproperty as prefix to store tokens. |
> separatearrayresults | When return value is an array, save result as property list ($resultproperty.[0..N] and $resultproperty.length) | `true`

> Example to get remote MBean attribute from default JMX connection

>         <jmx:get
>             name="Catalina:type=Manager,context=/servlets-examples,host=localhost"
>             attribute="maxActiveSessions"
>             resultproperty="servlets-examples.maxActiveSessions"
>         />

> Example to get and result array and split it at separate properties

>         <jmx:get
>             name="Catalina:type=ClusterSender,host=localhost"
>             attribute="senderObjectNames"
>             resultproperty="senderObjectNames"
>         />

> Access the senderObjectNames properties with:

>         ${senderObjectNames.length} give the number of returned sender list.
>         ${senderObjectNames.[0..N]} found all sender object names

> Example to get IDataSender attribute connected only when cluster is configured.

>     <jmx:query
>         failonerror="false"
>         name="Catalina:type=Cluster,host=${tomcat.application.host}"
>         resultproperty="cluster"
>     />
>     <jmx:get
>         name="Catalina:type=IDataSender,host=${tomcat.application.host},senderAddress=${cluster.backup.address},senderPort=${cluster.backup.port}"
>         attribute="connected"
>         resultproperty="datasender.connected"
>         if="cluster.0.name" />

JMXAccessorSetTask: set attribute value Ant task

> List of Attributes

> Attribute | Description | Default value
> --- | --- | ---
> name | Full qualified JMX ObjectName -- Catalina:type=Server |
> attribute | Existing MBean attribute (see Tomcat MBean description above) |
> value | value that set to attribute |
> type | type of the attribute. | java.lang.String
> ref | JMX Connection reference | `jmx.server`
> echo | Echo command usage (access and result) | `false`

> Example to set remote MBean attribute value

>         <jmx:set
>             name="Catalina:type=Manager,context=/servlets-examples,host=localhost"
>             attribute="maxActiveSessions"
>             value="500"
>             type="int"
>         />

JMXAccessorInvokeTask: invoke MBean operation Ant task

> List of Attributes

> Attribute | Description | Default value
> --- | --- | ---
> name | Full qualified JMX ObjectName -- Catalina:type=Server |
> operation | Existing MBean operation (see Tomcat funcspecs/fs-admin-opers.html). |
> ref | JMX Connection reference | `jmx.server`
> echo | Echo command usage (access and result) | `false`
> resultproperty | Save result at this project property |
> delimiter | Split result with delimiter (java.util.StringTokenizier) and use resultproperty as prefix to store tokens. |
> separatearrayresults | When return value is an array, save result as property list ($resultproperty.[0..N] and $resultproperty.length) | `true`

> stop an application

>         <jmx:invoke
>             name="Catalina:type=Manager,context=/servlets-examples,host=localhost"
>             operation="stop"/>

> Now you can find the sessionid at ${sessions.[0..N} properties and access the count with ${sessions.length} property.

> Example to get all sessionids

>         <jmx:invoke
>             name="Catalina:type=Manager,context=/servlets-examples,host=localhost"
>             operation="listSessionIds"
>             resultproperty="sessions"
>             delimiter=" "
>         />

> Now you can find the sessionid at ${sessions.[0..N} properties and access the count with ${sessions.length} property.

> Example to get remote MBean session attribute from session ${sessionid.0}

>         <jmx:invoke
>             name="Catalina:type=Manager,context=/ClusterTest,host=localhost"
>             operation="getSessionAttribute"
>             resultproperty="hello">
>              <arg value="${sessionid.0}"/>
>              <arg value="Hello" />
>      </jmx:invoke>

> Example to create a new access logger valve at vhost localhost

>      <jmx:invoke
>              name="Catalina:type=MBeanFactory"
>              operation="createAccessLoggerValve"
>              resultproperty="accessLoggerObjectName"
>      >
>          <arg value="Catalina:type=Host,host=localhost"/>
>      </jmx:invoke>

> Now you can find new MBean with name stored at ${accessLoggerObjectName} property.

JMXAccessorQueryTask: query MBean Ant task

> List of Attributes

> Attribute | Description | Default value
> --- | --- | ---
> name | JMX ObjectName query string -- Catalina:type=Manager,* |
> ref | JMX Connection reference | `jmx.server`
> echo | Echo command usage (access and result) | `false`
> resultproperty | Prefix project property name to all founded MBeans (mbeans.[0..N].objectname) |
> attributebinduing | bind ALL MBean attributes in addition to name | `false`
> delimiter | Split result with delimiter (java.util.StringTokenizier) and use resultproperty as prefix to store tokens. |
> separatearrayresults | When return value is an array, save result as property list ($resultproperty.[0..N] and $resultproperty.length) | `true`

> Get all Manager ObjectNames from all services and Hosts

>       <jmx:query
>                name="Catalina:type=Manager,*
>                resultproperty="manager" />

> Now you can find the Session Manager at ${manager.[0..N].name} properties and access the result object counter with ${manager.length} property.

> Example to get the Manager from servlet-examples application an bind all MBean properties

>       <jmx:query
>                name="Catalina:type=Manager,context=/servlet-examples,host=localhost*"
>                attributebinding="true"
>                resultproperty="manager.servletExamples" />

> Now you can find the manager at ${manager.servletExamples.0.name} property and can access all properties from this manager with ${manager.servletExamples.0.[manager attribute names]}. The result object counter from MBeans is stored ad ${manager.length} property.

> Example to get all MBeans from a server and store inside an external XML property file

>     <project name="jmx.query"
>                 xmlns:jmx="antlib:org.apache.catalina.ant.jmx"
>                 default="query-all" basedir=".">
>     <property name="jmx.host" value="localhost"/>
>     <property name="jmx.port" value="8050"/>
>     <property name="jmx.username" value="controlRole"/>
>     <property name="jmx.password" value="tomcat"/>

>     <target name="query-all" description="Query all MBeans of a server">
>     <!-- Configure connection -->
>     <jmx:open
>         host="${jmx.host}"
>         port="${jmx.port}"
>         ref="jmx.server"
>         username="${jmx.username}"
>         password="${jmx.password}"/>
>     <!-- Query MBean list -->
>     <jmx:query
>         name="*:*"
>         resultproperty="mbeans"
>         attributebinding="false"/>

>     <echoproperties
>         destfile="mbeans.properties"
>         prefix="mbeans."
>         format="xml"/>

>     <!-- Print results -->
>     <echo
>         message="Number of MBeans in server ${jmx.host}:${jmx.port} is ${mbeans.length}"/>
>     </target>
>     </project>

> Now you can find all MBeans inside the file mbeans.properties.

JMXAccessorCreateTask: remote create MBean Ant task

> List of Attributes

> Attribute | Description | Default value
> --- | --- | ---
> name | Full qualified JMX ObjectName -- Catalina:type=MBeanFactory |
> className | Existing MBean full qualified class name (see Tomcat MBean description above) |
> classLoader | ObjectName of server or web application classloader ( Catalina:type=ServerClassLoader,name=[server,common,shared] or Catalina:type=WebappClassLoader,context=/myapps,host=localhost) |
> ref | JMX Connection reference | `jmx.server`
> echo | Echo command usage (access and result) | `false`

> Example to create remote MBean

>         <jmx:create
>                  ref="${jmx.reference}"
>                  name="Catalina:type=MBeanFactory"
>                  className="org.apache.commons.modeler.BaseModelMBean"
>                  classLoader="Catalina:type=ServerClassLoader,name=server">
>                  <Arg value="org.apache.catalina.mbeans.MBeanFactory" />
>         </jmx:create>

> Warning: Many Tomcat MBeans can't be linked to their parent once
> created. The Valve, Cluster and Realm MBeans are not automatically
> connected with their parent. Use the MBeanFacrory create
> operation instead.

JMXAccessorUnregisterTask: remote unregister MBean Ant task

> List of Attributes

> Attribute | Description | Default value
> --- | --- | ---
> name | Full qualified JMX ObjectName -- Catalina:type=MBeanFactory |
> ref | JMX Connection reference | `jmx.server`
> echo | Echo command usage (access and result) | `false`

> Example to unregister remote MBean

>         <jmx:unregister
>             name="Catalina:type=MBeanFactory"
>         />

> Warning: A lot of Tomcat MBeans can't be unregister.
> The MBeans are not unlinked from their parent. Use MBeanFacrory
> remove operation instead.

JMXAccessorCondition: express condition

> List of Attributes

> Attribute | Description | Default value
> --- | --- | ---
> url | Set JMX connection URL - service:jmx:rmi:///jndi/rmi://localhost:8050/jmxrmi |
> host | Set the host, shortcut the very long URL syntax. | `localhost`
> port | Set the remote connection port | `8050`
> username | remote JMX connection user name. |
> password | remote JMX connection password. |
> ref | Name of the internal connection reference. With this attribute you can configure more the one connection inside the same Ant project. | `jmx.server`
> name | Full qualified JMX ObjectName -- Catalina:type=Server |
> echo | Echo condition usage (access and result) | `false`
> if | Only execute if a property of the given name exists in the current project. |
> unless | Only execute if a property of the given name not exists in the current project. |
> value (requiered) | Second arg for operation |
> type | Value type to express operation (support long and double) | `long`

> operation

> express one
> - == equals
> - != not equals
> - > greater than (&gt;)
> - >= greater than or equals (&gt;=)
> - < lesser than (&lt;)
> - <= lesser than or equals (&lt;=)

> `==`

> Wait for server connection and that cluster backup node is accessable

>           <target name="wait">
>              <waitfor maxwait="${maxwait}" maxwaitunit="second" timeoutproperty="server.timeout" >
>                 <and>
>                     <socket server="${server.name}" port="${server.port}"/>
>                     <http url="${url}"/>
>                     <jmx:condition
>                         operation="=="
>                         host="localhost"
>                         port="9014"
>                         username="controlRole"
>                         password="tomcat"
>                         name="Catalina:type=IDataSender,host=localhost,senderAddress=192.168.111.1,senderPort=9025"
>                         attribute="connected"
>                         value="true"
>                     />
>                 </and>
>             </waitfor>
>             <fail if="server.timeout" message="Server ${url} don't answer inside ${maxwait} sec" />
>             <echo message="Server ${url} alive" />
>         </target>

JMXAccessorEqualsCondition: equals MBean Ant condition

> List of Attributes

> Attribute | Description | Default value
> --- | --- | ---
> url | Set JMX connection URL - service:jmx:rmi:///jndi/rmi://localhost:8050/jmxrmi |
> host | Set the host, shortcut the very long URL syntax. | `localhost`
> port | Set the remote connection port | `8050`
> username | remote JMX connection user name. |
> password | remote JMX connection password. |
> ref | Name of the internal connection reference. With this attribute you can configure more the one connection inside the same Ant project. | `jmx.server`
> name | Full qualified JMX ObjectName -- Catalina:type=Server |
> echo | Echo condition usage (access and result) | `false`

> Wait for server connection and that cluster backup node is accessible

>           <target name="wait">
>              <waitfor maxwait="${maxwait}" maxwaitunit="second" timeoutproperty="server.timeout" >
>                 <and>
>                     <socket server="${server.name}" port="${server.port}"/>
>                     <http url="${url}"/>
>                     <jmx:equals
>                         host="localhost"
>                         port="9014"
>                         username="controlRole"
>                         password="tomcat"
>                         name="Catalina:type=IDataSender,host=localhost,senderAddress=192.168.111.1,senderPort=9025"
>                         attribute="connected"
>                         value="true"
>                     />
>                 </and>
>             </waitfor>
>             <fail if="server.timeout" message="Server ${url} don't answer inside ${maxwait} sec" />
>             <echo message="Server ${url} alive" />
>         </target>

Using the JMXProxyServlet

> Tomcat offers an alternative to using remote (or even local) JMX connections while still giving you access to everything JMX has to offer: Tomcat's JMXProxyServlet.

> The JMXProxyServlet allows a client to issue JMX queries via an HTTP interface. This technique offers the following advantages over using JMX directly from a client program:

> - You don't have to launch a full JVM and make a remote JMX connection just to ask for one small piece of data from a runing server
> - You don't have to know how to work with JMX connections
> - You don't need any of the complex configuration covered in the rest of this page
> - Your client program does not have to be written in Java

> A perfect example of JMX overkill can be seen in the case of popular server-monitoring software such as Nagios or Ichinga: if you want to monitor 10 items via JMX, you will have to launch 10 JVMs, make 10 JMX connections, and then shut them all down every few minutes. With the JMXProxyServlet, you can make 10 HTTP connections and be done with it.

> You can find out more information about the JMXProxyServlet in the documentation for the Tomcat manager.

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