Issue: Once connected to application, the option for perform GC is enabled button. However the heap dump button is greyed out. Also in the "application" menu its greyed out. Does it work for apps connected via jmx locally?
Description: Connecting via jmx to a websphere application. Stats and data come back but I want to see what's in memory for objects to look at a class object size. Heap dump button is greyed out.
Version: VisualVM 2.0.4
It looks to me that you are running a websphere on OpenJ9/IBM JDK. This will explain why heap dump is not available - unfortunately OpenJDK and OpenJ9 are substantially different in
Related
My spark java application is running on remote machine in our internal lab. To analyse the memory consumption of remote application, attached the remote application pid to JProfiler by using the 'attach mode' (with help of jpenable) from my local machine.
After attaching the remote application to JProfiler in local machine, 'Allocation tree' is showing only non-array object allocations. I want to know array allocations also from my local machine.
Please help me to know about the array allocation with JProfiler.
Thanks,
Nagendra R
When you attach to a running JVM with the JProfiler GUI, the session startup dialog has an option "Record array allocations". It is not selected by default, because it requires a large amount of reinstrumentations which can be very slow.
If array allocation spots are important for your analysis, it's better not to use attach mode but to pass the VM parameter for profiling as given by
Session->Integration wizards->New remote integration
Then the instrumentation is done while the classes are loaded.
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.
I have got a storm cluster running and I want to monitor its performance. I followed this blog and was able to measure the number of tuples received by a bolt using codahale metrics and display it in graphite.
My goal is to deploy a storm cluster on a lightweight computer such as beaglebone and for that I need to be able to monitor JVM parameters such as CPU, thread and memory usage of each Worker Process.
I really like codahale metrics and would like to continue using it in my application. Can anyone direct me as to how I can measure JVM parameters separately for each worker using codahale metrics?
I would really appreciate it if someone posted an example of how to get jvm metrics using codahale metrics.
Thanks,
Palak
I found an excellent tutorial here. Works like a charm.
Using VisualVM and JMX we can get the CPU usage,GC activity, class loading information, Heap size & Used Heap statistics, All the Threads information with statistics,
CPU & Memory profiling, performance monitoring, Memory leaks of worker nodes. And also you can take heap dumps and thread dumps, profiler snapshots.
STEPS for setup
STEP 1: Staring VisualVM
Java VisualVM is bundled with JDK version 6 update 7 or greater. Navigate to your JDK software's bin directory and double-click the Java VisualVM executable.
Alternatively, navigate to your JDK software's bin directory and type the following command at the command (shell) prompt: jvisualvm.
STEP 2: Adding MBean plugin
For JMX monitoring you need to add MBean plugin explicitly.
1, Choose Tools > Plugins from the main menu.
2, In the downloaded Plugins tab, Click Add Plugins
3, Select the Mbean plugin
After successfully adding MBean plugin you can see MBean tab in VisualVM and you can monitor JMX.
STEP 3: Local Monitoring
By default VisualVM will monitor all the applications running on the local JVM. No need to do any changes if your using Java 1.6 and above.
STEP 4: Remote Monitoring
To retrieve and display information on applications running on the remote host, the jstatd utility needs to be running on the remote host.
Steps to run jstatd
The jstatd tool is an RMI server application that monitors for the creation and termination of instrumented HotSpot Java virtual machines (JVMs) and provides an
interface to allow remote monitoring tools to attach to JVMs.
1, create a file with "jstatd.all.policy" file name and copy the below content
grant codebase "file:${java.home}/../lib/tools.jar" { permission java.security.AllPermission ;};
2, copy "jstatd.all.policy" file in java bin (Java\jdk1.7.0_10\bin) directory
3, Navigate to your JDK software's bin directory and type the following command at the command prompt: jstatd -J-Djava.security.policy=jstatd.all.policy.txt
4, to run jstatd admin privileges required, then only all the other users can connect it remote host.
It’s one time activity. (Run with background process in CIT and SIT)
To add a remote host in VisualVM, right-click the Remote node in the Applications window,
choose Add Remote Host and type the host name or IP address in the Add Remote Host dialog box.
When Java VisualVM is connected to a remote host, a node for the remote host appears under the Remote node in the Applications window.
You can expand the remote host node to view the applications running on the remote host.
Use jvisualvm.exe jdk/bin and you can monitor storm workers.
Jvisualvm can also point to remote Storm topology.
Download and add mbean plugin into jvisualvm.
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.
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.