Tomcat MBean Names

Table of Contents

Background

We will be using JMX MBeans as the technology for implementing manageability of Tomcat.

One of the key concepts of JMX is that each management bean has a unique name in the MBeanServer's registry, and that management applications can utilize these names to retrieve the MBean of interest to them for a particular management operation. This document proposes a naming convention for MBeans that allows easy calculation of the name for a particular MBean. For background information on JMX MBean names, see the Java Management Extensions Instrumentation and Agent Specification, version 1.0, section 6. In particular, we will be discussing the String Representation of ObjectName instances.

Catalina Object Hierarchy

Tomcat's servlet container implementation, called Catalina, can be represented as a hierarchy of objects that contain references to each other. The object hierarchy can be represented as a tree, or (isomorphically) based on the nesting of configuration elements in the conf/server.xml file that is traditionally used to configure Tomcat stand-alone.

The valid component nestings for Catalina are depicted in the following table, with columns that contain the following values:

  • Pattern - Nesting pattern of XML elements (in the conf/server.xml file) used to configure this component.
  • Cardinality - Minimum and maximum number of occurrences of this element at this nesting position, which also corresponds to the minimum and maximum number of Catalina components.
  • Identifier - Name of the JavaBeans property of this component that represents the unique identifier (within the nested hierarchy), if any.
  • MBean ObjectName - The portion of the MBean object name that appears after the domain name. For now, it should be assumed that all of these MBeans appear in the default JMX domain.

In the MBean ObjectName descriptions, several types of symbolic expressions are utilized to define variable text that is replaced by corresponding values:

  • ${GROUP} - One of the standard MBean names of the specified "group" category. For example, the expression ${REALM} represents the values like JDBCRealm and JAASRealm that identify the various MBeans for possible Realm components.
  • ${name} - Replaced by the value of property name from the current component.
  • ${parent.name} - Replaced by the value of property name from a parent of the current component, with the parent's type identified by parent.
  • ${###} - An arbitrary numeric identifier that preserves order but has no other particular meaning. In general, the server will assign numeric values to existing instances with large gaps into which new items can be configured if desired.
Pattern Cardinality Identifier MBean ObjectName
Server 1..1 (none) type=${SERVER}
Server / Listener 0..n (none) type=${LISTENER}, sequence=${###}
Server / Service 1..n name type=${SERVICE}, name=${name}
Server / Service / Connector 1..n address, port type=${CONNECTOR}, service=${service}, port=${port}, address=${address}
Server / Service / Connector / Factory 0..1 (none) (Only defined explicitly for an SSL connector, but can be treated as part of the connector component)
Server / Service / Connector / Listener 0..n (none) type=${LISTENER}, sequence=${###}, service=${service}, port=${connector.port}, address=${connector.address}
Server / Service / Engine 1..1 (none) type=${ENGINE}, service=${service.name}
Server / Service / Engine / Host 1..n name type=${HOST}, host=${name}, service=${service.name}
Server / Service / Engine / Host / Context 1..n path type=${CONTEXT}, context=${name}, host=${host.name}, service=${service.name}
Server / Service / Engine / Host / Context / Listener 0..n (none) type=${LISTENER}, sequence=${###}, context=${context.name}, host=${host.name}, service=${service.name}
Server / Service / Engine / Host / Context / Loader 0..1 (none) type=${LOADER}, context=${context.name}, host=${host.name}, service=${service.name}
Server / Service / Engine / Host / Context / Manager 0..1 (none) type=${MANAGER}, context=${context.name}, host=${host.name}, service=${service.name}
Server / Service / Engine / Host / Context / Realm 0..1 (none) type=${REALM}, context=${context.name}, host=${host.name}, service=${service.name}
Server / Service / Engine / Host / Context / Resources 0..1 (none) type=${RESOURCES}, context=${context.name}, host=${host.name}, service=${service.name}
Server / Service / Engine / Host / Context / Valve 0..n (none) type=${VALVE}, sequence=${###}, context=${context.name}, host=${host.name}, service=${service.name}
Server / Service / Engine / Host / Context / Wrapper 0..n (none) j2eeType=Servlet,name=${name}, WebModule=//${host.name}/${context.name}, J2EEApplication=${context.J2EEApplication}, J2EEServer=${context.J2EEServer}
Server / Service / Engine / Host / Context / WrapperLifecycle 0..n (none) type=${WRAPPER-LIFECYCLE}, sequence=${###}, context=${context.name}, host=${host.name}, service=${service.name}
Server / Service / Engine / Host / Context / WrapperListener 0..n (none) type=${WRAPPER-LISTENER}, sequence=${###}, context=${context.name}, host=${host.name}, service=${service.name}
Server / Service / Engine / Host / Listener 0..n (none) type=${LISTENER}, sequence=${###}, host=${host.name}, service=${service.name}
Server / Service / Engine / Host / Realm 0..1 (none) type=${REALM}, host=${host.name}, service=${service.name}
Server / Service / Engine / Host / Valve 0..n (none) type=${VALVE}, sequence=${###}, host=${host.name}, service=${service.name}
Server / Service / Engine / Listener 0..n (none) type=${LISTENER}, sequence=${###} (FIXME - disambiguate from Server / Service / Listener)
Server / Service / Engine / Realm 0..1 (none) type=${REALM}, service=${service.name}
Server / Service / Engine / Valve 0..n (none) type=${VALVE}, sequence=${###}, service=${service.name}
Server / Service / Listener 0..n (none) type=${LISTENER}, sequence=${###} (FIXME - disambiguate from Server / Service / Engine / Listener)

MBean Groups and Names

The following MBean names shall be defined in the resource file /org/apache/catalina/mbeans/mbeans-descriptors.xml (and therefore available for use within the Administration/Configuration web application for Tomcat):

MBean Name Group Name Catalina Interface Implementation Class
AccessLogValve VALVE org.apache.catalina.Valve org.apache.catalina.valves.AccessLogValve
BasicAuthenticator VALVE org.apache.catalina.Valve org.apache.catalina.authenticator.BasicAuthenticator
CertificatesValve VALVE org.apache.catalina.Valve org.apache.catalina.valves.CertificatesValve
ContextConfig LISTENER org.apache.catalina.LifecycleListener org.apache.catalina.startup.ContextConfig
ContextEnvironment RESOURCES org.apache.catalina.deploy.ContextEnvironment org.apache.catalina.deploy.ContextEnvironment
ContextResource RESOURCES org.apache.catalina.deploy.ContextResource org.apache.catalina.deploy.ContextResource
ContextResourceLink RESOURCES org.apache.catalina.deploy.ContextResourceLink org.apache.catalina.deploy.ContextResourceLink
CoyoteConnector CONNECTOR org.apache.catalina.Connector org.apache.coyote.tomcat4.CoyoteConnector
DigestAuthenticator VALVE org.apache.catalina.Valve org.apache.catalina.authenticator.DigestAuthenticator
EngineConfig LISTENER org.apache.catalina.LifecycleListener org.apache.catalina.startup.EngineConfig
ErrorReportValve VALVE org.apache.catalina.Valve org.apache.catalina.valves.ErrorReportValve
ErrorDispatcherValve VALVE org.apache.catalina.Valve org.apache.catalina.valves.ErrorDispatcherValve
FormAuthenticator VALVE org.apache.catalina.Valve org.apache.catalina.authenticator.FormAuthenticator
Group GROUP org.apache.catalina.Group org.apache.catalina.Group
HostConfig LISTENER org.apache.catalina.LifecycleListener org.apache.catalina.startup.HostConfig
HttpConnector10 CONNECTOR org.apache.catalina.Connector org.apache.catalina.connector.http10.HttpConnector
HttpConnector11 CONNECTOR org.apache.catalina.Connector org.apache.catalina.connector.http.HttpConnector
JAASRealm REALM org.apache.catalina.Realm org.apache.catalina.realm.JAASRealm
JDBCRealm REALM org.apache.catalina.Realm org.apache.catalina.realm.JDBCRealm
JDBCUserDatabase USERDATABASE org.apache.catalina.users.JDBCUserDatabase org.apache.catalina.users.JDBCUserDatabase
JNDIRealm REALM org.apache.catalina.Realm org.apache.catalina.realm.JNDIRealm
MBeanFactory org.apache.catalina.mbeans.MBeanFactory
MemoryRealm REALM org.apache.catalina.Realm org.apache.catalina.realm.MemoryRealm
MemoryUserDatabase USERDATABASE org.apache.catalina.users.MemoryUserDatabase org.apache.catalina.users.MemoryUserDatabase
NamingContextListener LISTENER org.apache.catalina.LifecycleListener org.apache.catalina.core.NamingContextListener
NamingResources RESOURCES org.apache.catalina.deploy.NamingResources org.apache.catalina.deploy.NamingResources
NonLoginAuthenticator VALVE org.apache.catalina.Valve org.apache.catalina.authenticator.NonLoginAuthenticator
PersistentManager MANAGER org.apache.catalina.Manager org.apache.catalina.session.PersistentManager
RemoteAddrValve VALVE org.apache.catalina.Valve org.apache.catalina.valves.RemoteAddrValve
RemoteHostValve VALVE org.apache.catalina.Valve org.apache.catalina.valves.RemoteHostValve
RequestDumperValve VALVE org.apache.catalina.Valve org.apache.catalina.valves.RequestDumperValve
Role ROLE org.apache.catalina.Role org.apache.catalina.Role
SingleSignOn VALVE org.apache.catalina.Valve org.apache.catalina.valves.SingleSignOn
SSLAuthenticator VALVE org.apache.catalina.Valve org.apache.catalina.authenticator.SSLAuthenticator
StandardContext CONTEXT org.apache.catalina.Context org.apache.catalina.core.StandardContext
StandardContextValve VALVE org.apache.catalina.Valve org.apache.catalina.core.StandardContextValve
StandardEngine ENGINE org.apache.catalina.Engine org.apache.catalina.core.StandardEngine
StandardEngineValve VALVE org.apache.catalina.Valve org.apache.catalina.core.StandardEngineValve
StandardHost HOST org.apache.catalina.Host org.apache.catalina.core.StandardHost
StandardHostValve VALVE org.apache.catalina.Valve org.apache.catalina.core.StandardHostValve
StandardManager MANAGER org.apache.catalina.Manager org.apache.catalina.session.StandardManager
StandardServer SERVER org.apache.catalina.Server org.apache.catalina.core.StandardServer
StandardService SERVICE org.apache.catalina.Service org.apache.catalina.core.StandardService
StandardWrapper WRAPPER org.apache.catalina.Wrapper org.apache.catalina.core.StandardWrapper
StandardWrapperValve VALVE org.apache.catalina.Valve org.apache.catalina.core.StandardWrapperValve
User USER org.apache.catalina.User org.apache.catalina.User
UserDatabaseRealm REALM org.apache.catalina.Realm org.apache.catalina.realm.UserDatabaseRealm
WebappLoader LOADER org.apache.catalina.Loader org.apache.catalina.loader.WebappLoader

JSR-88 Cross Reference

The deployment objects in the JSR-88 API object hierarchy correspond to the specified MBean names or groups as follows:

JSR-88 API Object MBean Name or Group Comments
DeployableObject ${CONTEXT} Context deployment info plus the corresponding WAR file
Target ${HOST}