1JSTATD(1) JDK Commands JSTATD(1)
2
6 jstatd - monitor the creation and termination of instrumented Java
7 HotSpot VMs
8
10 Note: This command is experimental and unsupported.
11 jstatd [options]
13 options
15 This represents the jstatd command-line options. See Options
16 for the jstatd Command.
17
19 The jstatd command is an RMI server application that monitors for the
20 creation and termination of instrumented Java HotSpot VMs and provides
21 an interface to enable remote monitoring tools, jstat and jps, to at‐
22 tach to JVMs that are running on the local host and collect information
23 about the JVM process.
24 The jstatd server requires an RMI registry on the local host. The js‐
26 tatd server attempts to attach to the RMI registry on the default port,
27 or on the port you specify with the -p port option. If an RMI registry
28 is not found, then one is created within the jstatd application that's
29 bound to the port that's indicated by the -p port option or to the de‐
30 fault RMI registry port when the -p port option is omitted. You can
31 stop the creation of an internal RMI registry by specifying the -nr op‐
32 tion.
33
35 -nr This option does not attempt to create an internal RMI registry
36 within the jstatd process when an existing RMI registry isn't
37 found.
38 -p port
40 This option sets the port number where the RMI registry is ex‐
41 pected to be found, or when not found, created if the -nr option
42 isn't specified.
43 -n rminame
45 This option sets the name to which the remote RMI object is
46 bound in the RMI registry. The default name is JStatRemoteHost.
47 If multiple jstatd servers are started on the same host, then
48 the name of the exported RMI object for each server can be made
49 unique by specifying this option. However, doing so requires
50 that the unique server name be included in the monitoring
51 client's hostid and vmid strings.
52 -Joption
54 This option passes a Java option to the JVM, where the option is
55 one of those described on the reference page for the Java appli‐
56 cation launcher. For example, -J-Xms48m sets the startup memory
57 to 48 MB. See java.
58
60 The jstatd server can monitor only JVMs for which it has the appropri‐
61 ate native access permissions. Therefore, the jstatd process must be
62 running with the same user credentials as the target JVMs. Some user
63 credentials, such as the root user in Oracle Solaris, Linux, and OS X
64 operating systems, have permission to access the instrumentation ex‐
65 ported by any JVM on the system. A jstatd process running with such
66 credentials can monitor any JVM on the system, but introduces addition‐
67 al security concerns.
68 The jstatd server doesn't provide any authentication of remote clients.
70 Therefore, running a jstatd server process exposes the instrumentation
71 export by all JVMs for which the jstatd process has access permissions
72 to any user on the network. This exposure might be undesirable in your
73 environment, and therefore, local security policies should be consid‐
74 ered before you start the jstatd process, particularly in production
75 environments or on networks that aren't secure.
76 The jstatd server installs an instance of RMISecurityPolicy when no
78 other security manager is installed, and therefore, requires a security
79 policy file to be specified. The policy file must conform to Default
80 Policy Implementation and Policy File Syntax.
81 If your security concerns can't be addressed with a customized policy
83 file, then the safest action is to not run the jstatd server and use
84 the jstat and jps tools locally. However, when using jps to get a list
85 of instrumented JVMs, the list will not include any JVMs running in
86 docker containers.
87
89 The interface exported by the jstatd process is proprietary and guaran‐
90 teed to change. Users and developers are discouraged from writing to
91 this interface.
92
94 The following are examples of the jstatd command. The jstatd scripts
95 automatically start the server in the background.
96
98 This example shows how to start a jstatd session with an internal RMI
99 registry. This example assumes that no other server is bound to the
100 default RMI registry port (port 1099).
101 jstatd -J-Djava.security.policy=all.policy
103
105 This example starts a jstatd session with an external RMI registry.
106 rmiregistry&
108 jstatd -J-Djava.security.policy=all.policy
109 This example starts a jstatd session with an external RMI registry
111 server on port 2020.
112 jrmiregistry 2020&
114 jstatd -J-Djava.security.policy=all.policy -p 2020
115 This example starts a jstatd session with an external RMI registry on
117 port 2020 that's bound to AlternateJstatdServerName.
118 rmiregistry 2020&
120 jstatd -J-Djava.security.policy=all.policy -p 2020 -n AlternateJstatdServerName
121
123 This example starts a jstatd session that doesn't create an RMI reg‐
124 istry when one isn't found. This example assumes an RMI registry is
125 already running. If an RMI registry isn't running, then an error mes‐
126 sage is displayed.
127 jstatd -J-Djava.security.policy=all.policy -nr
129
131 This example starts a jstatd session with RMI logging capabilities en‐
132 abled. This technique is useful as a troubleshooting aid or for moni‐
133 toring server activities.
134 jstatd -J-Djava.security.policy=all.policy -J-Djava.rmi.serv‐
136 er.logCalls=true
137JDK 14 2020 JSTATD(1)