I want to get a heap dump (suspected memory leak) of a certain Java process. However, when I start the jvisualvm tool, I cannot see any of the running Java processes.
I have Google'd around about this and have already found a couple of articles saying that you have to run the Java processes using the same JDK that you start the jvisualvm tool with in order for it to be able to see them. However, as far as I can see, this is already the case. I'm doing everything locally (I have remote access to the machine).
A couple of things to consider:
The processes are running on a firewalled Windows 2008 server
The processes are running using renamed versions of the JDK java.exe executable
As far as I can see the processes are running using the 1.6.0_18 JDK
One of the running processes starts an RMI registry
I'm waiting on a virtualized copy of the server so I can mess around with it (this is a production server). But in the meanwhile; any ideas as to why I cannot see any of the processes in jvisualvm (or jconsole for that matter)?
Well after I did a little research, it would appear that Peter's comment was correct. Because the JVM processes were launched by another user (the NETWORK SERVICE account because they were being started by a Windows service) they didn't show up in jvisualvm.
Workaround
Since I have access to the application configuration, I have found the following workaround, which involves explicitly enabling unsecured JMX for the target JVM:
Add the following JVM parameters:
-Dcom.sun.management.jmxremote.port=3333 -Dcom.sun.management.jmxremote.ssl=false -Dcom.sun.management.jmxremote.authenticate=false
Add the remote process to jvisualvm using JMX by click File -> Add JMX Connection. You can connect to the process using port 3333. Obviously you can change the port if you want.
Link to article explaining this in a little more detail: http://download.oracle.com/javase/6/docs/technotes/guides/visualvm/jmx_connections.html
Notes
It's probably not a good idea to keep the JVM settings permanently, as they would allow anyone to connect to the JVM via JMX.
You can also add authentication to the JMX JVM parameters if you want to.
The simplest way is to execute jvisualvm as administrator (win: "run as administrator"). Which is not ideal but works. All java processes are visible then.
Related
I am evaluating Jprofiler.
In this process, i tried to attach a profiling scheme to a java process on a remote machine.
it provided a profiling port number, using which could connect to remote process and proceed.
But, once a profiling port is attached, i did not find anyway to de-associate the profiling port from the java process.
I would like to know if there is anyway to remove the profiling port from the java process without killing the java process.
Would appreciate your response.
Thank you very much.
Dev
There is no way to do that because the JVM does not provide a way to unload an agent.
I have scheduled Java Agents. I would like to use a profiler to monitor the JVM to see how the server is performing.
When developing and testing, I run the agent from my Domino Designer from my workstation.
The workstation and server have a Java JRE installed.
Domino and Notes appears to have its own JVM directory.
Tools like VisualVM seem to connect to the computers JVM, how would I use something like VisualVM to monitor the JVM used to run xpages and agents?
Based on this QA and my attempts many years ago I think you can't do it your way.
Edited to reflect comments...
Anyway, I was able to profile XPages indirectly via heap monitoring or NSD dumps (that's the extreme - for freezing code).
For XPages, take a look at this project XPages Toolbox. For Java Agent, try native agent profiler:
http://searchdomino.techtarget.com/tutorial/How-the-Agent-Profiler-tool-improves-Notes-Domino-performance
http://www.ibm.com/support/knowledgecenter/SSVRGU_9.0.0/com.ibm.designer.domino.main.doc/H_PROFILING_AGENTS_AND_WEB_SERVICES_STEPS.html
In worst case, try to debug your agent to get a picture of collections it iterates or paths it goes in the code execution. Just be aware - remote debugger tends to attach to one of two JVMs - agent manager's or http's task. Be sure it attaches to the right one.
How can I get aheap dump from a remote JVM which runs on linux with WL application server?
When I run locally on a windows machine I know how to get a dump. But, how do I get a dump from the user acceptance test server? Thanks in advance.
You can use JMX to connect to the remote application server (it should be enabled in advance) and use the HotSpotDiagnostic MBean which allows taking a heap dump.
You can use JConsole or VisualVM for invoking the MBean operation.
This post by Mike Haller describes how to use this method with JVisualVM.
Since its a *-nix system, and if you have the necessary privieleges, then it would be easy to connect to using SSH protocol:
Connect to the remote machine:
ssh user#remote-machine-ip-address
Enter the user password once prompted for it (it should be the one for the user on the remote machine and not your current system user).
Generate your heap dump using the jmap utility (JDK binaries path should be availble into your system PATH variable or use a full path to it):
jmap -dump:format=b,file=cheap.bin <pid>
There are three steps:
ssh to your server
ssh <your_user_name>#<remote_ip>
jmap to trigger memory dump
jmap -dump:format=b,file=<your_file_name> <your_jvm_pid>
visualize the heap by jhat (here 512m is the size limit, you can set it depends on the leak's file size, like -J-Xmx2g)
jhat -J-Xmx512m <your_file_name>
jhat -port 7401 <your_file_name>
I write a blog to help analyze performance issue: Performance Optimization
I've used Visual VM successfully for thread dumps and heap dumps, however, you don't list your JAVA version?
JAVA Visual VM is no longer shipped with JAVA, but can still be downloaded here and it's still being maintained. They just did a new minor release: October 19, 2021: VisualVM 2.1.1 Released.
VisualVM has also been distributed in Oracle JDK 6~8 as Java VisualVM.
It has been discontinued in Oracle JDK 9.
Here are steps for connecting to the VM from Dzone, VisualVM: Monitoring Remote JVM Over SSH (JMX Or Not)
For other alternatives, the Baeldung JAVA site, which has great information and tutorials, has A Guide to Java Profilers.
Hi i am very new to Jprofiler & Linux.
I am trying to Monitor my Apache Tomcat server installed on a linux machine from Jprofiler remote profiling which is installed on windows machine. Kindly help me in the procedure in detail.
I tried all the Help i could get from google but still stuck..any help will is appreciated. Thanks in advance.
In any case, you should extract the JProfiler tar.gz file for Linux on the remote machine. No further configuration is required on the remote side. On the local side you need a full installation of JProfiler.
There are two ways to get remote profiling to work:
A. Attach to the running Tomcat process
Execute the command line utility bin/jpenable in the JProfiler distribution on the remote machine and select the Tomcat process. The JVM will then be ready for profiling. If the profiled JVM is not listed, execute jpenable as the same user that runs the Tomcat JVM. If that does help, use alternative B.
On the local machine, create a session of type "Attach to profiled JVM (local or remote)", specify the host name of the remote machine and the profiling port that was set with jpenable.
When you start session, the JProfiler GUI will connect to the remote machine and you will see profiling data.
B. Use the integration wizard
Execute the command line uutility bin/jpintegrate in the JProfiler distribution on the remote machine and select your application server and follow the subsequent steps.
Then, proceed as in alternative A. This option is actually preferable to alternative A and unless you have to profile an already running JVM, you should take this route.
I would like to attach to a WebSphere JVM and obtain useful data like garbage collectors' names and their collection counts, thread counts, heap/non-heap memory usage, JVM uptime etc. However, this link gives the list of MBeans available with the WebSphere JVM -
http://pic.dhe.ibm.com/infocenter/wasinfo/v6r1/index.jsp?topic=%2Fcom.ibm.websphere.javadoc.wsfep.doc%2Fweb%2FmbeanDocs%2Findex.html
These MBeans don't seem to offer any data that I require. Is there any other way to obtain the data? I shall be using JMX to gather it.
If you're a corporate with bucks to spend I would suggest a product like Wily Introscope which runs an agent along with your JVM to collect all the metrics that you are after. I have used it with Websphere servers. Searching for an Open Source alternative I came across GlassBox which may provide a low cost alternative for you.
I'm not aware of any default MBeans that will provide the coverage you're after. It's typically the big Java vendors that provide this type of functionality.
[Update]
Having done something recently using VisualVM with Websphere 7, for the purposes of real-time monitoring/troubleshooting, I thought I would share my knowledge. VisualVM comes with the standard Sun JDK and you will find it installed here: JAVA_HOME\bin\jvisualvm.exe
To enable the JRE in Websphere to allow VisualVM to connect you must add the following JVM parameters using the Websphere Admin Console
Go To: Application Servers > [server_name] > Java and Process Management > Process definition > Java Virtual Machine > Generic JVM arguments
-Djavax.management.builder.initial=
-Dcom.sun.management.jmxremote
-Dcom.sun.management.jmxremote.authenticate=false
-Dcom.sun.management.jmxremote.ssl=false
-Dcom.sun.management.jmxremote.port=1099
-Dcom.sun.management.jmxremote.local.only=false
Make sure that the port number you have chosen above is not already in use
netstat -ap | grep 1099
Restart the server and you will be able to connect using VisualVM to see Uptime, Threads, Heap and GC profiles.
I see that Sun have also documented how you can write your own Java JMX client to read these values.
You could go with the suggestions provided by Brad and Andreas.
I would like to give you some insights into some of the tools that should be explored
(1) Tivoli Performance Viewer. This should provide some information about the JVM.
(2) IBM Health Center -> http://www.ibm.com/developerworks/java/jdk/tools/healthcenter/
Both of these should provide you a lot of info that you require.
Try them out
The JVM statistics are provided by the platform MXBeans. If you need to collect this data over a short period of time, then you could use a tool such as VisualVM. It's a bit tricky to configure this to connect to a WebSphere instance, but it is possible. One way to do that (there are other options) is described here:
http://code.google.com/p/xm4was/wiki/VisualVMHowTo
If you want to collect the data over a longer period of time, then you need a monitoring system. At work, I wrote a plugin for the Open Source RHQ enterprise management system that adds support for WebSphere. I'm in the process of releasing this plugin as an Open Source project, but at the time of writing, I have not yet published the documentation and there is also no downloadable release yet. Only the source code is available right now. I will try to complete that in the next weeks. If you are interested in this project, please let me know.