I want to monitor JVM performance on my production environment. I have installed only JRE, not JDK, Hence i can't use jstat, jconsole etc. to monitor the JVM performance.
Can somebody please help to understand how can i monitor JVM performance in this scenario?
Is there any way to achieve this?
(please note that i don't want to monitor it remotely through JMX or something else. i would like to install local agent in each machine which will send the metrics to server at the interval of 1 minute.)
Thanks,
KS
If you manage to get JMX up and running on your VM (from the comment), you can then use jmxterm or jmxfetch to push these JMX metrics into a metrics system (like graphite or Datadog).
If you have enough patience and time to write, you can probably have a look at JVMTI. You can write your code in C/C++ and run it along your Java Process and you can gather information about the JVM without affecting it.
Another simple and naive way is to start your VM with a javaagent written in java but JVMTI is even better than that. The most crucial difference between the javaagent and JVMTI app is derived from the loading mechanics. While the agents are loaded inside the heap, they are governed by the same JVM. Whereas the JVMTI agents are not governed by the JVM rules and are thus not affected by the JVM internals such as the GC or runtime error handling.
You can even give Java Mission Control a try if you're using JDK7 or above :)
Jolokia is a java agent you can use to expose JMX as http. Run jmx2graphite and get those metrics into Graphite. The link includes instructions on Graphite installation (10 minutes)
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 am automating web-application tests that are driven by Selenium architecture in Windows VMs, connecting via Windows Remote Desktop. It became known to me that Flash/SWF and other in-browser elements behave differently if the VM window is opened/shown (all is cool) and when the window is closed (or maybe even minimized). Which means that browsers/plugins engage some optimization if no one watches the screen (I might be wrong with that - if so - please correct me).
As a (working) workaround, installing VNC (and logging into it at least once before running the tests) helps. From that moment noone needs to "watch" the monitor.
I think that the same functionality/system calls is used by (for example) movie players that cancel the screensaver during the film watching.
The question is if any special daemon was written for those purposes, so I won't need to connect to those machines by VNC, but only to run the daemon.
Update: http://www.jddesign.co.uk/products/freeware/freeware_programs.htm - meanwhile found this utility, checking if it will do the job. Advices are still welcomed.
Update N2: the utility above doesn't do the job.
What you experience is the standard render optimization: The OS will ignore all rendering commands if the window isn't visible.
My guess is that VM tools "minimize" the whole desktop to save memory as long as no one is connected.
On Unix, I'd write a small script which runs the VNC viewer when the tests are started.
[EDIT] What you're looking for is a kind of /dev/null device for VNC connections.
Here is a solution that might work: Download the sources for the TightVNC Java Viewer (license: GPL) and remove all the rendering code.
That should allow you to start a headless VNC client for your tests.
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.
What are the key use cases for the use of virtualization -- that is, running one or more "virtual PCs" using software such as VMWare and Microsoft Virtual PC -- for software development?
Also -- are there other instances/uses of virtualization that aren't covered by my definition above (use of a tool like MS Virtual PC or VMWare), and that are useful to developers?
My impetus for asking is this StackOverflow comment by Metro Smurf asserting "You'll wonder how you ever developed without it!", regarding use of virtualization.
(Please include just one use case per response. Thanks!)
Application testing in multiple environments is one obvious use of virtualization that I'm aware of. Testing your application on other operating systems (without requiring additional physical computers to do so), as well as testing that involves software that generally only allows you to install a single version on a given machine (such as the Internet Explorer browser; running both IE6 and IE7 on the same machine is not an officially supported configuration), are good candidates for virtual machine usage.
If your build-server is running in a VM, you can make a snapshots of it for every software release in order to be 100% sure that you can recreate the build environment (in case you want to make patches to old releases, for example).
If you set up snapshots of your development environment (and back them up) it can be very easy to resume productivity if your computer breaks down. When your machine breaks down right before your release - and you can resume immediately with all your tools installed and configured, it can be a lifesaver.
The simplest case which applies to my current situation is that we have a complex client-server environment and with virtualization every developer can very quickly get a baseline set of operating systems to deploy their local build to and verify end to end functionality.
Locally you have your dev box, and N client boxes which get re-initialized as fresh OSes each time you want to try a build. Essentially it's the test environment equivalent of a 'make clean' where even the client workstation gets replaced with a new OS.
Quickly distributing environments between team members is a very nice use case to for virtualization especially if you have a lot of various components, tools, etc.. This can save you a ton of time with new hires, contractors, or other individuals who need an environment quickly.
Many presenters use a VM for presentations - it allows them to revert immediately to reset the presentation for the next day, transfer all presentation materials quickly between computers, and not have to show your attendees your messy My Documents folder.
Using virtualization for sales activities is also a great use case. You can take a snapshot at a particular time that you can save as your demo baseline. Then once you run through the demonstration and change the data, etc. you can restore back to your previous baseline for future demonstrations. You can also capture multiple baselines and pick and choose which baseline best fits the upcoming demo.
Test environments. If you have more than one setup that a system needs to be targeted for (e.g. Windows & Linux, XP & Vista) then a machine with lots of RAM and VMWare (or on of the others) is a good way to manage the environments.
Another is developing on one system and targeting another. For example, at one point I did some J2EE work on a workstation running Linux where the client was I.E. 5.5. A VM with Windows 2000 and IE 5.5 would let me test the application.
Reasons I use virtual machines for development.
Isolate different development environments.
Testing environments.
Easy recovery due to computer hardware failure/upgrade.
Ability to "roll-back" changes to your development environment if something corrupts it.
Currently, I am using VirtualBox for my VM setup. I used to use VirtualPC, but I REALLY hated not having any type of "snapshot" feature (like VMware and VirtualBox have).
We develop software for use in our SaaS application, our production environment has a large number of servers and their software environment needs to be absolutely predictable; we can't have ANYTHING installed extra, or absent from our development machines.
Moreover, our application requires a number of different server types in order to function properly (at least 7 last time I counted); mostly they can't be installed on the same (virtual) machine - at least, not without violating the "same software as production" requirement.
In order to have a consistent environment, it's necessary to use VMs. I don't know how anyone ever manages without them.
Snapshots and rollbacks are nice too, but I use them only occasionally (really useful during installation / upgrade tests).
Suppose you're developing a new version of your software, and checking that the upgrade from the previous version works correctly... how long does it take to do a test cycle without being able to rollback the box? Do you have to reinstall the OS then the old version? Can you guarantee that the uninstall really uninstalls everything?
Being able to test/retest your deployment process is a huge savings.
Developing Add-Ins for different versions of Microsoft Office (using Visual Studio Tools for Office).
My main work machine has Office 2007. When I work with Add-Ins for Office 2003 I use a virtual machine with Visual Studio and Office 2003.
I'm suprised that nobody has mentioned the VMware record/replay feature (awesome video demo) which is great for debugging.
I have a headless server running ESXi which runs various machines for building installers (so I don't have to give up processing power on my desktop), automated testing (server is faster than any desktop) and various test environments (about 20 different configurations) so that the support team can easily jump onto a configuration that closely matches a customers system.
When you have one really beefy server running VMs that can be shared between support, test and dev teams, you introduce huge cost savings. In all, we're running ~25 VMs on ESXi (dual-quad core Xeon 2.5G + 8Gb RAM) shared between 5-10 people, some of the developers use Virtual PC and then I use VMware Workstation on my desktop. All of the Mac users here use VMware Fusion as well
I am surprised that no one has mentioned the benefit of increased security by isolating, for example, the database server and web server in different VM's.
Some server applications can use VMs too. When one vm is not used much, the server can locate the resources to other vms.
Some sort of test environment: if you are debugging malware (either writing or developing a pill against it) it is not clever to use the real OS. The only possible disadvantage is that the viruses can detect that they are being run in the virtualization. :( One of the possibilities to do it is because the VM engines can emulate a finite set of hardware.