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jstatd(1)                        JDK Commands                        jstatd(1)




NAME

       jstatd  -  monitor  the  creation  and termination of instrumented Java
       HotSpot VMs


SYNOPSIS

       Note: This command is experimental and unsupported.

       jstatd [options]

       options
              This represents the jstatd command-line  options.   See  Options
              for the jstatd Command.


DESCRIPTION

       The  jstatd  command is an RMI server application that monitors for the
       creation and termination of instrumented Java HotSpot VMs and  provides
       an  interface  to enable remote monitoring tools, jstat and jps, to at-
       tach to JVMs that are running on the local host and collect information
       about the JVM process.

       The  jstatd server requires an RMI registry on the local host.  The js-
       tatd server attempts to attach to the RMI registry on the default port,
       or on the port you specify with the -p port option.  If an RMI registry
       is not found, then one is created within the jstatd application  that's
       bound  to the port that's indicated by the -p port option or to the de-
       fault RMI registry port when the -p port option is  omitted.   You  can
       stop the creation of an internal RMI registry by specifying the -nr op-
       tion.


OPTIONS FOR THE JSTATD COMMAND

       -nr    This option does not attempt to create an internal RMI  registry
              within  the  jstatd  process when an existing RMI registry isn't
              found.

       -p port
              This option sets the port number where the RMI registry  is  ex-
              pected to be found, or when not found, created if the -nr option
              isn't specified.

       -r rmiport
              This option sets the port number to which the RMI  connector  is
              bound.  If not specified a random available port is used.

       -n rminame
              This  option  sets  the  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, then
              the name of the exported RMI object for each server can be  made
              unique  by  specifying  this option.  However, doing so requires
              that the unique  server  name  be  included  in  the  monitoring
              client's hostid and vmid strings.

       -Joption
              This option passes a Java option to the JVM, where the option is
              one of those described on the reference page for the Java appli-
              cation launcher.  For example, -J-Xms48m sets the startup memory
              to 48 MB.  See java.


SECURITY

       The jstatd server can monitor only JVMs for which it has the  appropri-
       ate  native  access permissions.  Therefore, the jstatd process must be
       running with the same user credentials as the target JVMs.   Some  user
       credentials, such as the root user in Linux and OS X operating systems,
       have permission to access the instrumentation exported by  any  JVM  on
       the system.  A jstatd process running with such credentials can monitor
       any JVM on the system, but introduces additional security concerns.

       The jstatd server doesn't provide any authentication of remote clients.
       Therefore,  running a jstatd server process exposes the instrumentation
       export by all JVMs for which the jstatd process has access  permissions
       to any user on the network.  This exposure might be undesirable in your
       environment, and therefore, local security policies should  be  consid-
       ered  before  you  start the jstatd process, particularly in production
       environments or on networks that aren't secure.

       The jstatd server installs an instance  of  RMISecurityPolicy  when  no
       other security manager is installed, and therefore, requires a security
       policy file to be specified.  The policy file must conform  to  Default
       Policy Implementation and Policy File Syntax.

       If  your  security concerns can't be addressed with a customized policy
       file, then the safest action is to not run the jstatd  server  and  use
       the jstat and jps tools locally.  However, when using jps to get a list
       of instrumented JVMs, the list will not include  any  JVMs  running  in
       docker containers.


REMOTE INTERFACE

       The interface exported by the jstatd process is proprietary and guaran-
       teed to change.  Users and developers are discouraged from  writing  to
       this interface.


EXAMPLES

       The  following  are examples of the jstatd command.  The jstatd scripts
       automatically start the server in the background.


INTERNAL RMI REGISTRY

       This example shows how to start a jstatd session 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


EXTERNAL RMI REGISTRY

       This example starts a jstatd session with an external RMI registry.

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

       This example starts a jstatd session  with  an  external  RMI  registry
       server on port 2020.

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

       This  example  starts  a  jstatd  session with an external RMI registry
       server on port 2020 and JMX connector bound to port 2021.

              jrmiregistry 2020&
              jstatd -J-Djava.security.policy=all.policy -p 2020 -r 2021

       This example starts a jstatd session with an external RMI  registry  on
       port 2020 that's bound to AlternateJstatdServerName.

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


STOP THE CREATION OF AN IN-PROCESS RMI REGISTRY

       This  example  starts  a jstatd session that doesn't create an RMI reg-
       istry when one isn't found.  This example assumes an  RMI  registry  is
       already  running.  If an RMI registry isn't running, then an error mes-
       sage is displayed.

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


ENABLE RMI LOGGING

       This example starts a jstatd session with RMI logging capabilities  en-
       abled.   This technique is useful as a troubleshooting aid or for moni-
       toring server activities.

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



JDK 15                               2020                            jstatd(1)

openjdk 15.0.2 - Generated Tue Feb 23 16:02:37 CST 2021
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