JMX ThreadInfo Plug-in - Technical Reference

connection

Identifies the set of settings required to connect to the monitored Java application.

connection > serviceUrl

Specifies the location where the monitored application resides, e.g.

service:jmx:rmi:///jndi/rmi://192.168.10.161:25000/jmxrmi

connection > username

Identifies a particular setting required to connect to the monitored Java application.

connection > password

Specifies the password with which to connect to a secured Java application. To set an encrypted password, click on the "Set Password" button, then enter and confirm the password to be used.

connection > timeout

Specifies the number of milliseconds to wait for connections to be established. This setting should not be used unless it is found that the sampler seems to be waiting for inordinate amounts of time to connect to an application which is clearly down. This allows a timeout which the user decides is appropriate, for which to wait for a connection, before deciding that the application should be considered down.

headlineLabels

Allows the user to configure just those headlines that they are interested in. If this section is blank, then all the headlines will be displayed in the dataview.

headlineLabels > headlineLabel

Identifies one of a prefixed set of thread attributes which should be displayed as a headline.

Possible values:

Mandatory: No

tablecolLabels

Allows the user to specify one or more column headers to display. If this is not enabled then all the column headers are displayed.

Mandatory: No

tablecolLabels > tablecolLabel

Identifies one of a prefixed set of thread attributes which should be displayed in a table column

Possible values:

Mandatory: No

jproperties

Allows the user to specify additional flags with which to configure the JVM which the probe creates.

Mandatory: No

jproperties > jproperty

Allows user to specify a comma separated list of supported JVM arguments. This comprises those flags which begin with -D or the -verbose flag. Flags starting with -X are JVM implementation dependent and may or may not work.

For example,

JProperties=-Xms2M,-Xmx4M,-verbose

Mandatory: No

logJavaMemoryInfo

Whether java heap usage should be logged every 10 minutes to the netprobe log file or not.

Possible values:

Additional Files

The plug-in requires the following files to be present in the net probe directory:

In addition, Microsoft.VC80.CRT redistributables are required when using AES-256 passwords in Windows machines.

Attribute Types

The requested attribute must be either a primitive (e.g. boolean, short, integer, long, float, double) or a reference to an object for which toString() has been overidden to provide a sensible human viewable value. If an attribute is requested which violates these constraints, then the information published to the dataview is likely to not be useful. Please see section 2.7 for some exceptions to this rule.

Whitespaces In MBean Aliases

The plug-in does not accept mbean aliases that contain leading or trailing whitespace. It does however, accept mbean aliases which contain whitespace within the actual alias.

Securing the application

The first thing to ensure is that we have a valid rolename-permission pair in the access file that resides inside the JRE installation directory i.e. $JRE/management/jmxremote.access:

By default the following rolename-permission pairs exist:

monitorRole     readonly
controlRole     readwrite

So we add our own entry choosing kyoto as our rolename and granting it readwrite access.

Our file should now look like this:

monitorRole     readonly
controlRole     readwrite
kyoto           readwrite

We then create a local password file called jmxremote.password in our current working directory. We need to chmod 600 the file otherwise Java will complain and not use the file. We then add our rolename along with origami as the password of our choice.

The jmxremote.password file should now look like this:

kyoto           origami

Assuming our application is a standalone class file called JmxServer we can now start the application passing the following flags to the Java command:

java -Dcom.sun.management.jmxremote
     -Dcom.sun.management.jmxremote.port=5003
     -Dcom.sun.management.jmxremote.ssl=false
     -Dcom.sun.management.jmxremote.authenticate=true
     -D com.sun.management.jmxremote.password.file=/jmxremote.password
     JmxServer

Note: We have now specified true for the authenticate flag and passed in the absolute path of where to find the jmxremote.password file.

Finally we configure a jmx-threadinfo plugin to connect to our secured application and retrieve some information about the threads currently running in its JVM:

// Sampler Descriptor
Plugin=JMX-THREADINFO
Settings=@Settings
GroupName=JMX
ViewName=THREADS
HeadlineLabels=@Headlines
TableColLabels=@TableCols

// Additional Data section(Settings)
ServiceURL=service:jmx:rmi:///jndi/rmi://192.168.10.200:5003/jmxrmi
username=kyoto
password=origami

Note: When setting a password, user will have the option of entering the password in encrypted form. Plugin settings will not show the password in plaintext, but in encrypted text.

// Additional Data section(Headlines)
DaemonThreadCount
PeakThreadCount

// Additional Data section(TableCols)
threadName
threadId
threadState