Not able to Connect a Remote Host to the VisualVM - monitoring

I am new to Java and I'm facing a problem in connecting a Remote Host to the JVisualVM.
I've searched the Internet and followed all the steps mentioned there but still am not able to resolve the issue. The steps I followed are:
I started the jstatd on the remote server by first creating a jstatd.all.policy file in the $JAVA_HOME/bin. The file contained: grant codebase "file:${java.home}/../lib/tools.jar" { permission java.security.AllPermission;};
I started the Jstatd as jstatd -J-Djava.security.policy=jstatd.all.policy
I started the Java application on the remote host as :
java -Dcom.sun.management.jmxremote -Dcom.sun.management.jmxremote.port=9000 -Dcom.sun.management.jmxremote.ssl=false -Dcom.sun.management.jmxremote.authenticate=false application_name
I then started as instance of the JVisualVM on my local machine and as I added the remote host, it got connected but i wasn't able to see any of the Java processes.
Can anyone please help me with this.
Thanks.

I encountered similar problems when connecting to Glassfish application server. See solutions that worked for me as they can be same for You:
Try setting on your application:
-Djava.rmi.server.hostname=*Remote_Server_External_IP_Address*
The mentioned IP address should be server external IP (may sound silly but it worked for me). The main problem in my case was JMX pointing to the localhost and looping. In config files the exact IP address should be set to the remote host. I described it as 'Problem 2' In my blog: handling connection problems
If Firewall block is an issue then I recommend trying XMing with SSH tunnel (which is simple to set). Here is instruction, if You encounter problems setting it:
Remote use of VisualVM with Xming (my blog)
Biggest advantage of using XMing is that it will work almost always when SSH is enabled. You just have to place VisualVM files on the remote host and run it from command line. XWindow will show VisualVM Window on Your local computer.
There is a chance that it is VisualVM issue - try using some other tool just to verify what is wrong. I recommend JConsole. It works similar to VisualVM and I also described details on my blog

You need to start jstatd with the additional option that points to the server's external IP or hostname:
statd -J-Djava.security.policy=jstatd.all.policy -J-Djava.rmi.server.hostname=my_server_ip/hostname
Answer based on: https://java.net/projects/visualvm/lists/users/archive/2010-03/message/8

To connect to a remote VM you have to start that remote VM with specific options:
java
-Dcom.sun.management.jmxremote
-Dcom.sun.management.jmxremote.port=9000
-Dcom.sun.management.jmxremote.ssl=false
-Dcom.sun.management.jmxremote.authenticate=false
class
After the VM is started, go to your VisualVM and do the following:
File -> Add JMX Connection
Type: yourHostName:9000 and click OK
On the left you will have the added JMX connection, double click on it and that's it!
More details on the Java Monitoring and Management Platform can be found here.

Here are the steps to do this:
Launch an ejstatd in your remote host this way (in ejstatd folder): mvn exec:java -Djava.rmi.server.hostname=<remote_host_name> -Dexec.args="-pr 1099 -ph 1100 -pv 1101" (used for "jstatd" type connection) (only specify -Djava.rmi.server.hostname if the hostname of your remote host does not match with the one you are seeing from your local network)
Launch your Java application with those additional Java parameters: -Dcom.sun.management.jmxremote -Dcom.sun.management.jmxremote.ssl=false -Dcom.sun.management.jmxremote.authenticate=false -Dcom.sun.management.jmxremote.port=1102 -Dcom.sun.management.jmxremote.rmi.port=1102 -Djava.rmi.server.hostname=<remote_host_name> (used for "JMX" type connection) (same remark as the previous point for -Djava.rmi.server.hostname)
Open those 4 ports on your remote host and make them available to your local machine: 1099, 1100, 1101 and 1102
Launch JVisualVM
Right-click on "Remote" > "Add Remote Host..." and enter your remote host name in "Host name" (if you don't use the port 1099, you can change this in the "Advanced Settings")
Right-click on the remote host you've just created > "Add JMX Connection..." and enter "<remote_host_name>:1102" in "Connection" input, and check "Do not require SSL connection"
Your Java process will appear twice: one from the "jstatd" connection type, and one from the "JMX" connection type.
Disclaimer: I'm the author of the open source ejstatd tool.

Start jstatd in nohup on the server which needs to be monitored and connect VisualVM to the jstatd port, following below steps:
Step 1 : Create start-jstatd.sh and copy the below content:
nohup jstatd -p 1099 -J-Djava.security.policy=<(echo 'grant codebase "file:${java.home}/../lib/tools.jar" {permission java.security.AllPermission;};') &
Step 2: Give executable permission to the file:
$ chmod a+rwx start-jstatd.sh
Step 3: Start jstatd:
$ sh start-jstatd.sh
Step 4: Add Remote Host in VisualVM:
Step 5: Add JMX Connection to the Remote Host, as shown in the below image and Click OK button:

Related

Making Jenkins localhost publicly available within the same network

I am running my jenkins on localhost on my macmini which is my remote machine. All the tests are also running on that mac mini. However i want to share that localhost:8080 jenkins url to make it publickly so something like the eg.71.65.187.98:8080. so within the same network my coworkers can open the url and see the jenkins. How can i do that? without using any external service?
Run ifconfig in the terminal. it'll show all the network interfaces on your Mac. One of them is the network your machine is actively connected to.
If your Mac is on a wired connection that should be en0. Make a note of the address after inet, that should be the address your machine uses
It depends on how you start your jenkins server. If you use the generic war file then you can add the command flags --httpPort=yourPort --httpListenAddress=yourAdress.
A complete command could look like this:
java "${JAVA_OPTS}" -Xms256m -Xmx256m -jar jenkins.war --httpPort=8787 --httpListenAddress=192.168.0.171
Depending on your OS it may be possible that you need to tell your firewall to open the desired port.
I was able to solve the issue since i installed my jenkins using brew. first I needed to :
nano /usr/local/opt/jenkins-lts/homebrew.mxcl.jenkins-lts.plist
then change the httpListenAddress to 0.0.0.0
Then by using ifconfig on the terminal i was able to get my IP address and i was able the use IP address:8080 inside my network.

Why can't I set up a jenkins agent on the same machine as the master (WIndows 10), Jenkins on localhost?

Can't set up an agent on the same machine as the master node in Jenkins. The Jenkins instance is on localhost as is the agent. The main problem I'm getting is:
at
yah de yah.....
at java.lang.Thread.run(Unknown Source)
Caused by: java.net.UnknownHostException: http://192.168.0.1:8080/
Here's what I tried:
1 - Configure agent launched via ssh, Host is http://192.168.0.1:8080/ (also tried 127.0.0.1 and localhost here but the URL in Jenkins config is as shown) with Jenkins admin password. Used 'Known host file Verification Strategy' Advanced setting uses port 22. Tried Jenkins Global Security settings with fixed port 22, 50000 and random port setting.
Also toggled Windows OpenSSH for client and server with the above combinations.
Configure agent by Connecting it to the master; other options as default. Got 'Agent is offline because Jenkins failed to launch the agent process' and got the 'Launch' button for webstart. Clicked on that; nothing happened (that I saw) but the file did appear in my downloads folder.
Copied the file to another directory, opened a command window in that directory and entered the 'headless' command shown in the window with the webstart button. Got:
Error: Unable to access jarfile agent.jar
Seems no matter what I try I can't connect to http://192.168.0.1:8080/
Is this some sort of tunneling issue where I need to expose localhost even though I'm not going over the Internet? I needed to do that to get my localhost Jenkins install to talk to GitHub.
Been reading numerous articles,watched videos - seems most of the material out there is for a 'real' use of creating agents on separate machines.
Any advice would be MOST appreciated.

Jenkins not accessible with http://<hostname>:8080 in Windows server 2012

I have installed Jenkins in Windows server 2012 64-bit machine and want to make it available in internal network.
I have added --httpListenAddress to 0.0.0.0 and restarted Jenkins and tried to access it with http://hostname:8080 but no page shows up(though It showing Jenkins icon in URL bar). However http://localhost:8080 works fine.
Further I checked the firewall inbound rule for the Jenkins but seems it has no issues.
I tried to catch the listening ports with "netstat -aon | find /i "8080" and found <host ip address>:8080 FIN_WAIT_2 which sign towards that the request is stuck(May be I am wrong).
I am clueless what exactly is blocking to use hostname with jenkins. Please share your solution if you already fixed this issue.
You might try adding a Windows Firewall rule. Go to Windows Firewall, Advanced Configuration, Inbound Rules rule and create an Allow rule for the specific version of java.exe you have installed.
This worked for us with the drawback that every time you upgrade Java, you must also modify the firewall rule. This is because Java creates a new subfolder for every version. We've tried using %JAVA_HOME% in firewall rules but it doesn't seem to work. We were on Windows Server 2012R2 at the time.
Similar answer here: https://stackoverflow.com/a/17479566/7752
On the server open a new command prompt and type
ipconfig
You should get a list of ips. Open a browser and type each up followed by 8080 for e.g.
http://202.123.2.1:8080
If Jenkins opens up, from another computer ping the ip and see if you can get a ping reply
ping 202.123.2.1
If you get a ping reply, you can access jenkins from any pc on the network by typing in the ip and port number.
Now to get to the hostname,you need to edit your host file
c:\Windows\System32\Drivers\etc\hosts
Type in the ip followed by the hostname
202.123.2.1 jenkins
If you can't get through, you need to open port 8080. See https://www.vultr.com/docs/how-to-open-a-port-in-windows-firewall-on-windows-server-2012
You cannot access from outside the machine because Jenkins Service does not have credentials to use that machine, only from localhost is accessible.
This is how to enter the credentials in Jenkins service.
In the Windows search bar, type services then enter.
Then scroll down to Jenkins and double-click on it.
In Jenkins Properties, select the tab "Log On".
Select Check box "This account"
Update your username and password.
Voila! Now Jenkins web can connect to the Jenkins machine via Jenkins service.

Remote JMX Technology

anybody work on Remote Monitoring in java (JMX).
I have to monitor Remote Tomcat instance on Linux system and i need to monitor on local window machine.
i am accessing Remote Tomcat using Putty through VPN.
Please help..
I have tried by give jmx port in catalina.sh file of tomcat with variable JAVA_OPT and further tunneling in Putty ,but i m not able to access via localhost with port ,
also by using service jmx command.
please help !!!
Thanks for your time and support in advance ..
Remote JMX needs two ports to operate properly. And the second one (the RMI registry port) is by default picked randomly causing problems with firewalls etc.
Since JDK7u4 you can use
-Dcom.sun.management.jmxremote.rmi.port=<port>
to set the RMI port to be used.
See this blog for more detailed steps.

call jmx operation on a local running process

I have a java process on a linux server, which runs with this option: -Dcom.sun.management.jmxremote
So I cannot just connect to this process via jconsole running on my local pc (because neither port nor -Dcom.sun.management.jmxremote.ssl=false options are set up).
But still, how can I connect to the application and run some operations over some of its MBeans? It this possible? I have a ssh access to the server and would be able to run it "locally" on the server (but not changing the options unfortunately)
According to JMX documentation the -Dcom.sun.management.jmxremote option
Enables the JMX remote agent and local monitoring via JMX connector published on a private
interface used by jconsole. The jconsole tool can use this connector if it is executed by
the same user ID as the user ID that started the agent. No password or access files are
checked for requests coming via this connector.
The naming is a bit unfortunate because it in fact enables the local monitoring only.
Since you can not change the options but can access the server via SSH the only option is to use X server forwarding (ssh -X ...) and run jconsole (or better yet jvisualvm which has specific optimisations for running remotely).

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