src/jdk.jstatd/share/man/jstatd.md - openjdk/jdk25u - Git at Google


            
            ---

            
            # Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.

            
            # DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

            
            #

            
            # This code is free software; you can redistribute it and/or modify it

            
            # under the terms of the GNU General Public License version 2 only, as

            
            # published by the Free Software Foundation.

            
            #

            
            # This code is distributed in the hope that it will be useful, but WITHOUT

            
            # ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

            
            # FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

            
            # version 2 for more details (a copy is included in the LICENSE file that

            
            # accompanied this code).

            
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            # You should have received a copy of the GNU General Public License version

            
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            title: 'JSTATD(1) JDK @@VERSION_SHORT@@ | JDK Commands'

            
            date: @@COPYRIGHT_YEAR@@

            
            lang: en

            
            ---


            ## Name


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


            ## Synopsis


            **WARNING:** This command is experimental, unsupported, and deprecated. It will be removed in a future release.


            `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 attach 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 `jstatd`

            
            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 default RMI registry port

            
            when the `-p` `port` option is omitted. You can stop the creation of an

            
            internal RMI registry by specifying the `-nr` option.


            ## 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 expected 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.


            `-J`*option*

            
            :   This option passes a Java `option` to the JVM, where the option is one of

            
                those described on the reference page for the Java application launcher.

            
                For example, `-J-Xms48m` sets the startup memory to 48 MB. See

            
                [java](java.html).


            ## Security


            The `jstatd` server can monitor only 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 Linux and macOS 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 considered before you start the

            
            `jstatd` process, particularly in production environments or on networks that

            
            aren't secure.


            For security purposes, the `jstatd` server uses an RMI ObjectInputFilter to allow

            
            only essential classes to be deserialized.


            If your security concerns can't be addressed,

            
            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 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 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`


            ## External RMI Registry


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


            ```

            
            rmiregistry&

            
            jstatd

            
            ```


            This example starts a `jstatd` session with an external RMI registry server on

            
            port `2020`.


            ```

            
            jrmiregistry 2020&

            
            jstatd -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 -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 -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 registry when

            
            one isn't found. This example assumes an RMI registry is already running. If an

            
            RMI registry isn't running, then an error message is displayed.


            >   `jstatd -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.rmi.server.logCalls=true`
	---
	# Copyright (c) 2004, 2024, Oracle and/or its affiliates. All rights reserved.
	# DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	#
	# This code is free software; you can redistribute it and/or modify it
	# under the terms of the GNU General Public License version 2 only, as
	# published by the Free Software Foundation.
	#
	# This code is distributed in the hope that it will be useful, but WITHOUT
	# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	# FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	# version 2 for more details (a copy is included in the LICENSE file that
	# accompanied this code).
	#
	# You should have received a copy of the GNU General Public License version
	# 2 along with this work; if not, write to the Free Software Foundation,
	# Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	#
	# Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	# or visit www.oracle.com if you need additional information or have any
	# questions.
	#

	title: 'JSTATD(1) JDK @@VERSION_SHORT@@ \| JDK Commands'
	date: @@COPYRIGHT_YEAR@@
	lang: en
	---

	## Name

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

	## Synopsis

	WARNING: This command is experimental, unsupported, and deprecated. It will be removed in a future release.

	`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 attach 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 `jstatd`
	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 default RMI registry port
	when the `-p` `port` option is omitted. You can stop the creation of an
	internal RMI registry by specifying the `-nr` option.

	## 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 expected 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.

	`-J`option
	: This option passes a Java `option` to the JVM, where the option is one of
	those described on the reference page for the Java application launcher.
	For example, `-J-Xms48m` sets the startup memory to 48 MB. See
	[java](java.html).

	## Security

	The `jstatd` server can monitor only 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 Linux and macOS 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 considered before you start the
	`jstatd` process, particularly in production environments or on networks that
	aren't secure.

	For security purposes, the `jstatd` server uses an RMI ObjectInputFilter to allow
	only essential classes to be deserialized.

	If your security concerns can't be addressed,
	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 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 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`

	## External RMI Registry

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

	```
	rmiregistry&
	jstatd
	```

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

	```
	jrmiregistry 2020&
	jstatd -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 -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 -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 registry when
	one isn't found. This example assumes an RMI registry is already running. If an
	RMI registry isn't running, then an error message is displayed.

	> `jstatd -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.rmi.server.logCalls=true`