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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 cre-
       ation 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 inter-
       nal 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 contradictory 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 speci-
                      fied.

       -n rminame     Name to which the remote RMI object is bound in the  RMI
                      registry. The default name is JStatRemoteHost. If multi-
                      ple 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 appropri-
       ate 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 exercised when running the  jstatd  server  with  credentials
       that  allow wide exposure, such as running the server with root permis-
       sions 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 per-
       formed locally. Alternatively, the security policy  file  can  be  cus-
       tomized 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  reg-
       istry.  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  reg-
       istry 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 moni-
       toring 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 vari-
       ables,  other shells or command interpreters may require different syn-
       tax.


SEE ALSO

       java(1) jps(1) jstat(1) rmiregistry(1)



                                 13 June 2004                        jstatd(1)

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