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jstatd(1)                                                                                          jstatd(1)



NAME
       jstatd - Virtual Machine jstat Daemon

SYNOPSIS
       jstatd [ options ]

DESCRIPTION
       The  jstatd  tool  is  an  RMI  server  application that monitors for the creation and termination of
       instrumented HotSpot Java virtual machines (JVMs) and provides a interface to allow remote monitoring
       tools to attach to JVMs running on the local host.

       The  jstatd server requires the presence of an RMI registry on the local host. The jstatd server will
       attempt to attach to the RMI registry on the default port, or on the port indicated by  the  -p  port
       option.   If an RMI registry is not found, one will be created within the jstatd application bound to
       the port indicated by the -p port option or to the default RMI registry port if -p port  is  omitted.
       Creation of an internal RMI registry can be inhibited by specifying the -nr option.

       NOTE  -  This  utility  is unsupported and may or may not be available in future versions of the J2SE
       SDK.  It is not currently available on the Windows 98 and Windows ME platforms.

PARAMETERS
       options        Command-line options. The options may be in any order. If there are redundant or  con-tradictory contradictory
                      tradictory options, the last option specified will take precedence.

OPTIONS
       The jstatd command supports the following options:

       -nr            Do  not  attempt  to create an internal RMI registry within the jstatd process when an
                      existing RMI registry is not found.

       -p port        Port number where the RMI registry is expected to be found, or, if not found,  created
                      if -nr is not specified.

       -n rminame     Name  to which the remote RMI object is bound in the RMI registry. The default name is
                      JStatRemoteHost. If multiple jstatd servers are started on the same host, the name  of
                      the  exported  RMI  object  for  each  server can be made unique by by specifying this
                      option. However, doing so will require that the unique server name be included in  the
                      monitoring client's hostid and vmid strings.

       -Joption       Pass  option  to  the  java  launcher called by javac. For example, -J-Xms48m sets the
                      startup memory to 48 megabytes. It is a common convention for -J to  pass  options  to
                      the underlying VM executing applications written in Java.

SECURITY
       The  jstatd  server  installs  an instance of RMISecurityPolicy if no other security manager has been
       installed and therefore requires a security policy file to be specified. The policy file must conform
       to the default policy implementation's Policy File Syntax.  The policy file can be specified with the
       -J-Djava.security.policy=file

       The following policy file will allow the jstatd server to run without any security  exceptions.  This
       policy  is  less  liberal  then granting all permissions to all codebases, but is more liberal than a
       policy that grants the minimal permissions to run the jstatd server.

              grant codebase "file:${java.home}/../lib/tools.jar" {
                    permission java.security.AllPermission;
              };

       To use this policy, copy the text into a file called jstatd.all.policy and run the jstatd  server  as
       follows:

              jstatd -J-Djava.security.policy=jstatd.all.policy

       For sites with more restrictive security practices, Sun recommends that the jstatd security policy be
       customized to meet your specific needs.

       The jstatd server can only monitor JVMs for which it has the appropriate access permissions. However,
       jstatd does not perform any user level authentication or authorization checking.  Therefore, it opens
       access to the instrumentation exported by the JVMs for which the jstatd server  has  the  appropriate
       access  permissions,  allowing arbitrary users on the network to monitor JVMs that might otherwise be
       inaccessible. Such exposure may be unacceptable in your environment. Particular care should be  exer-cised exercised
       cised  when  running the jstatd server with credentials that allow wide exposure, such as running the
       server with root permissions on UNIX based systems.

       The exposure introduced by the jstatd server can be  eliminated  by  not  running  the  server,  thus
       requiring  all monitoring activities to be performed locally. Alternatively, the security policy file
       can be customized to limit access to specific trusted hosts.

REMOTE INTERFACE
       The interface exported by the jstatd process is proprietary and is guaranteed to  change.  Users  and
       developers are discouraged from writing to this interface.

EXAMPLES
       Here  are  some  examples  of  starting  jstatd. Note that the jstatd scripts automatically start the
       server in the background.

   Using Internal RMI Registry
       This example demonstrates starting jstatd with an internal RMI registry. This example assumes that no
       other server is bound to the default RMI Registry port (port 1099).

              jstatd -J-Djava.security.policy=all.policy

   Using External RMI Registry
       This example demonstrates starting jstatd with a external RMI registry.

              rmiregistry&
              jstatd -J-Djava.security.policy=all.policy

       This example demonstrates starting jstatd with an external RMI registry server on port 2020.

              rmiregistry 2020&
              jstatd -J-Djava.security.policy=all.policy -p 2020

       This  example  demonstrates starting jstatd with an external RMI registry on port 2020, bound to name
       AlternateJstatdServerName.

              rmiregistry 2020&
              jstatd -J-Djava.security.policy=all.policy -p 2020 -n AlternateJstatdServerName

   Inhibiting creation of an in-process RMI registry
       This example demonstrates starting jstatd such that it will not create a RMI registry if one  is  not
       found.  This  example  assumes an RMI registry is already running. If it is not, an appropriate error
       message is emitted.

              jstatd -nr

   Enabling RMI logging capabilities
       This example demonstrates starting jstatd with RMI logging capabilities enabled.  This  technique  is
       useful as a troubleshooting aid or for monitoring server activities.

              jstatd -J-Djava.security.policy=all.policy -J-Djava.rmi.server.logCalls=true

       This  example uses the Bourne Shell syntax for setting environment variables, other shells or command
       interpreters may require different syntax.

SEE ALSO
       Java (1) jps (1) jstat (1) rmiregistry (1)



                                                13 June 2004                                       jstatd(1)