man > jstatd(1)

jstatd(1)                                 Monitoring Tools                                 jstatd(1)

NAME
       jstatd - Monitors Java Virtual Machines (JVMs) and enables remote monitoring tools to attach
       to JVMs. This command is experimental and unsupported.

SYNOPSIS
       jstatd [ options ]


       options
              The command-line options. See Options.

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 to attach to JVMs that are running on the local host.

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

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

       -p port
              The port number where the RMI registry is expected to be found,  or  when  not  found,
              created if the -nr option 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,  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
              Passes  option  to  the  JVM,  where  option  is  one  of the options described on the
              reference page for the Java application launcher.  For  example,  -J-Xms48m  sets  the
              startup memory to 48 MB. See java(1).

SECURITY
       The  jstatd  server  can  only  monitor  JVMs  for which it has the appropriate 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 UNIX-based 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 does not 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 considered before you
       start the jstatd process, particularly in production environments or on networks that are not
       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   at
       http://docs.oracle.com/javase/8/docs/technotes/guides/security/PolicyFiles.html

       The following policy file allows the jstatd server to run without  any  security  exceptions.
       This  policy  is  less  liberal  than granting all permissions to all code bases, 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 setting, 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, it is possible to use a custom policy
       file to limit access to specific trusted  hosts  or  networks,  though  such  techniques  are
       subject  to IP address spoofing attacks. If your security concerns cannot 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.

REMOTE INTERFACE
       The  interface  exported by the jstatd process is proprietary and guaranteed 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 hos 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 a 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 on port 2020 that is 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 does not create an RMI registry  when  one  is  not
       found.  This  example  assumes  an RMI registry is already running. If an RMI registry is not
       running, then an error message is displayed.

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


   ENABLE RMI LOGGING
       This example starts a jstatd session 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


SEE ALSO
       • java(1)

       • jps(1)

       • jstat(1)

       • rmiregistry(1)

JDK 8                                     21 November 2013                                 jstatd(1)