jstatd-java-1.7.0-openjdk(1)

1jstatd(1)                   General Commands Manual                  jstatd(1)
2
3
4

Name

6       jstatd - Virtual Machine jstat Daemon
7

SYNOPSIS

9       jstatd [ options ]
10
11

PARAMETERS

13          options
14             Command-line  options.  The options may be in any order. If there
15             are redundant or contradictory options, the last option specified
16             will take precedence.
17
18

DESCRIPTION

20       The jstatd tool is an RMI server application that monitors for the cre‐
21       ation and termination of instrumented  HotSpot  Java  virtual  machines
22       (JVMs)  and  provides  a  interface to allow remote monitoring tools to
23       attach to JVMs running on the local host.
24
25       The jstatd server requires the presence of an RMI registry on the local
26       host.  The  jstatd server will attempt to attach to the RMI registry on
27       the default port, or on the port indicated by the -p port option. If an
28       RMI registry is not found, one will be created within the jstatd appli‐
29       cation bound to the port indicated by the -p  port  option  or  to  the
30       default  RMI registry port if -p port is omitted. Creation of an inter‐
31       nal RMI registry can be inhibited by specifying the -nr option.
32
33       NOTE: This utility is unsupported and may or may not  be  available  in
34       future  versions  of the JDK. It is not currently available on the Win‐
35       dows 98 and Windows ME platforms.
36

OPTIONS

38       The jstatd command supports the following options:
39
40          -nr
41             Do not attempt to create an  internal  RMI  registry  within  the
42             jstatd process when an existing RMI registry is not found.
43
44          -p  port
45             Port  number  where the RMI registry is expected to be found, or,
46             if not found, created if -nr is not specified.
47
48          -n  rminame
49             Name to which the remote RMI object is bound in the RMI registry.
50             The  default  name is JStatRemoteHost. If multiple jstatd servers
51             are started on the same host, the name of the exported RMI object
52             for  each  server  can  be made unique by specifying this option.
53             However, doing so will require that the  unique  server  name  be
54             included in the monitoring client's hostid and vmid strings.
55
56          -Joption
57             Pass  option  to  the java launcher called by javac. For example,
58             -J-Xms48m sets the startup memory to 48 megabytes. It is a common
59             convention  for -J to pass options to the underlying VM executing
60             applications written in Java.
61
62

SECURITY

64       The jstatd server can only monitor JVMs for which it has the  appropri‐
65       ate native access permissions. Therefor the jstatd process must be run‐
66       ning with the same user credentials as the target JVMs. Some user  cre‐
67       dentials, such as the root user in UNIX(TM) based systems, have permis‐
68       sion to access the instrumentation exported by any JVM on the system. A
69       jstatd process running with such credentials can monitor any JVM on the
70       system, but introduces additional security concerns.
71
72       The jstatd  server  does  not  provide  any  authentication  of  remote
73       clients. Therefore, running a jstatd server process exposes the instru‐
74       mentation export by all JVMs for which the jstatd  process  has  access
75       permissions  to any user on the network. This exposure may be undesire‐
76       able in your environment and local security policies should be  consid‐
77       ered  before  starting  the  jstatd process, particularly in production
78       environments or on unsecure networks.
79
80       The jstatd server installs an instance of RMISecurityPolicy if no other
81       security  manager  has been installed and therefore requires a security
82       policy file to be specified.  The  policy  file  must  conform  to  the
83       default policy implementation's Policy File Syntax @
84       http://docs.oracle.com/javase/7/docs/technotes/guides/security/Policy‐
85       Files.html.
86
87       The following policy file will allow the jstatd server to run without
88       any security exceptions. This policy is less liberal then granting all
89       permissions to all codebases, but is more liberal than a policy that
90       grants the minimal permissions to run the jstatd server.
91
92       grant codebase "file:${java.home}/../lib/tools.jar" {
93          permission java.security.AllPermission;
94       };
95
96
97       To use this policy, copy the text into a file called jstatd.all.policy
98       and run the jstatd server as follows:
99
100       jstatd -J-Djava.security.policy=jstatd.all.policy
101
102
103       For sites with more restrictive security practices, it is possible to
104       use a custom policy file to limit access to specific trusted hosts or
105       networks, though such techniques are subject to IP addreess spoofing
106       attacks. If your security concerns cannot be addressed with a custom‐
107       ized policy file, then the safest action is to not run the jstatd
108       server and use the jstat and jps tools locally.
109

REMOTE INTERFACE

111       The interface exported by the jstatd process is proprietary and is
112       guaranteed to change. Users and developers are discouraged from writing
113       to this interface.
114

EXAMPLES

116       Here are some examples of starting jstatd. Note that the jstatd scripts
117       automatically start the server in the background.
118
119   Using Internal RMI Registry
120       This example demonstrates starting jstatd with an internal RMI reg‐
121       istry. This example assumes that no other server is bound to the
122       default RMI Registry port (port 1099).
123
124       jstatd -J-Djava.security.policy=all.policy
125
126
127   Using External RMI Registry
128       This example demonstrates starting jstatd with a external RMI registry.
129
130       rmiregistry&
131       jstatd -J-Djava.security.policy=all.policy
132
133
134       This example demonstrates starting jstatd with an external RMI registry
135       server on port 2020.
136
137       rmiregistry 2020&
138       jstatd -J-Djava.security.policy=all.policy -p 2020
139
140
141       This example demonstrates starting jstatd with an external RMI registry
142       on port 2020, bound to name AlternateJstatdServerName.
143
144       rmiregistry 2020&
145       jstatd -J-Djava.security.policy=all.policy -p 2020 -n AlternateJstatdServerName
146
147
148   Inhibiting creation of an in-process RMI registry
149       This example demonstrates starting jstatd such that it will not create
150       a RMI registry if one is not found. This example assumes an RMI reg‐
151       istry is already running. If it is not, an appropriate error message is
152       emitted.
153
154       jstatd -J-Djava.security.policy=all.policy -nr
155
156
157   Enabling RMI logging capabilities.
158       This example demonstrates starting jstatd with RMI logging capabilities
159       enabled. This technique is useful as a troubleshooting aid or for moni‐
160       toring server activities.
161
162       jstatd -J-Djava.security.policy=all.policy -J-Djava.rmi.server.logCalls=true
163
164