JMX ThreadInfo
Introduction Copied
The Geneos JMX ThreadInfo Plug-in allows for the monitoring of the thread sub-system of JMX-enabled applications. These include applications which have been written to expose their state by implementing the JMX specification, for example, Tomcat 6.0.
Java requirements Copied
- You must have Java installed on the machine running the Netprobe. For information on supported Java versions, see Java support in Geneos Compatibility Matrix.
- Once you have Java installed, configure the environment variables required by the Netprobe so that it can locate the required resource files. For guidance, see Configure the Java environment.
The Java installation and environment configuration is a common source of errors for users setting up Java-based components and plug-ins. It is recommended to read Configure the Java environment to help you understand your Java installation.
Views Copied
The plug-in produces a single view, a representative example of which is given below:
Headline Legend
| Name | Description |
|---|---|
| DaemonThreadCount | the current number of live daemon threads |
| PeakThreadCount | the peak live thread count since the Java virtual machine started or peak was reset |
| ThreadCount | the current number of live threads including both daemon and non-daemon threads |
| TotalStartedThreadCount | the total number of threads created and also started since the Java virtual machine started. |
| ThreadContentionMonitoringEnabled | if thread contention monitoring is enabled |
| ThreadContentionMonitoringSupported | if the Java virtual machine supports thread contention monitoring |
| ThreadCpuTimeEnabled | if thread CPU time measurement is enabled. |
| ThreadCpuTimeSupported | if the Java virtual machine implementation supports CPU time measurement for any thread |
Table Legend
| Name | Description |
|---|---|
| threadName | The name of a particular thread in the jvm |
| threadId | The id for a particular thread in the jvm |
| threadState | One of the following states: NEW, RUNNABLE, BLOCKED, WAITING, TIMED_WAITING, TERMINATED |
| suspended | Whether the thread is suspended or not |
| blockedCount | the total number of times that this thread blocked to enter or reenter a monitor |
| blockedTime | the approximate accumulated elapsed time (in milliseconds) that this thread has blocked to enter or reenter a monitor since thread contention monitoring is enabled |
| lockOwnerId | the ID of the thread which owns the object for which this thread is blocked waiting |
| lockOwnerName | the name of the thread which owns the object for which this thread is blocked waiting |
| lockName | the string representation of the object for which this thread is blocked waiting |
| waitedCount | the total number of times that this thread waited for notification |
| waitedTime | the approximate accumulated elapsed time (in milliseconds) that this thread has waited for notification since thread contention monitoring is enabled |
| inNative | Tests if this thread is executing native code via the Java Native Interface (JNI). |
| threadCpuTime | the total CPU time for this thread in nanoseconds |
| threadUserTime | the CPU time that this thread has executed in user mode in nanoseconds |
Plug-in Configuration Copied
You can safely update most of the configuration options on this plug-in without causing the Netprobe to restart. The exception is the jproperties option. If you update this option, then the Netprobe restarts.
connection Copied
Identifies the set of settings required to connect to the monitored Java application.
connection > serviceUrl Copied
Specifies the location where the monitored application resides, e.g.
service:jmx:rmi:///jndi/rmi://192.168.10.161:25000/jmxrmi
connection > username Copied
Identifies a particular setting required to connect to the monitored Java application.
connection > password Copied
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 Copied
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 Copied
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 Copied
Identifies one of a prefixed set of thread attributes which should be displayed as a headline.
Possible values:
| Setting | Description |
|---|---|
| DaemonThreadCount | the current number of live daemon threads |
| PeakThreadCount | the peak live thread count since the Java virtual machine started or peak was reset |
| ThreadCount | the current number of live threads including both daemon and non-daemon threads |
| TotalStartedThreadCount | the total number of threads created and also started since the Java virtual machine started. |
| ThreadContentionMonitoringEnabled | if thread contention monitoring is enabled |
| ThreadContentionMonitoringSupported | if the Java virtual machine supports thread contention monitoring |
| ThreadCpuTimeEnabled | if thread CPU time measurement is enabled. |
| ThreadCpuTimeSupported | if the Java virtual machine implementation supports CPU time measurement for any thread |
Mandatory: No
tablecolLabels Copied
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 Copied
Identifies one of a prefixed set of thread attributes which should be displayed in a table column
Possible values:
| Setting | Description |
|---|---|
| threadId | The id for a particular thread in the jvm |
| threadState | One of the following states: NEW, RUNNABLE, BLOCKED, WAITING, TIMED_WAITING, TERMINATED |
| suspended | Whether the thread is suspended or not |
| blockedCount | the total number of times that this thread blocked to enter or reenter a monitor |
| blockedTime | the approximate accumulated elapsed time (in milliseconds) that this thread has blocked to enter or reenter a monitor since thread contention monitoring is enabled |
| lockOwnerId | the ID of the thread which owns the object for which this thread is blocked waiting |
| lockOwnerName | the name of the thread which owns the object for which this thread is blocked waiting |
| lockName | the string representation of the object for which this thread is blocked waiting |
| waitedCount | the total number of times that this thread waited for notification |
| waitedTime | the approximate accumulated elapsed time (in milliseconds) that this thread has waited for notification since thread contention monitoring is enabled |
| inNative | Tests if this thread is executing native code via the Java Native Interface (JNI). |
| threadCpuTime | the total CPU time for this thread in nanoseconds |
| threadUserTime | the CPU time that this thread has executed in user mode in nanoseconds |
Mandatory: No
jproperties Copied
Allows the user to specify additional flags with which to configure the JVM which the probe creates.
Caution: Java flags that are configured on this setting are inherited by all Java-based samplers running on the same Netprobe. For a full list of Java-based plugins, see Overview in Configure the Java environment.
For example, consider the following scenario:
- Netprobe
Ais running the JMX and REST API samplers. - The JMX sampler uses the
jpropertiessetting to enable TSL. - A REST API sampler on Netprobe
Ainherits the values configured in thejpropertiessetting. It is possible that the REST API sampler may encounter errors if thejpropertiesflags require data that is not present in the REST API sampler. To address this the JMX and REST API samplers must be run on separate Netprobes. Mandatory: No
jproperties > jproperty Copied
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 Copied
Whether java heap usage should be logged every 10 minutes to the netprobe log file or not.
Possible values:
| Setting | Description |
|---|---|
| true | java heap usage should be logged every 10 minutes |
| false | java heap usage should not be logged every 10 minutes |
Mandatory: No
Default: false
Additional Files Copied
The plug-in requires the following files to be present in the net probe directory:
ITRS provided files:
- launchpad.jar
- jmx-plugins.jar
- jep-2.3.0.jar
- launchPad.dll (Windows) or liblaunchpad.so (UNIX/LINUX)
In addition, Microsoft.VC80.CRT redistributables are required when using AES-256 passwords in Windows machines.
Current Limitations Copied
Attribute Types Copied
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 Copied
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.
Connecting to applications using password and access files Copied
Java supports the use of password files and access files to restrict access to a jmx-enabled application. In this case the plugin also needs to provide a username and password before being allowed to connect to and retrieve information from the application.
We explain how to configure a sample Java application for authenticated access and then show how to configure the plugin to connect to that application. The instructions given are suitable for UNIX and LINUX.
Please see http://java.sun.com/j2se/1.5.0/docs/guide/management/security-windows.html for instructions on how to secure an application for windows.
Securing the application Copied
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