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JMX remote connection failure to Java application running on Ubuntu

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I have been trying to remote monitoring my application which was running on Ubuntu server using Jconsole and I kept on getting connection failure.
When I run the same application on my Ubuntu desktop I did managed to connect to it using Jconsole.

I wrote a small program to help me investigate the problem:


public class JmxTest {
public static void main(String[] args) {

try {
Thread.sleep(Integer.MAX_VALUE);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}

and I ran it with the following properties on my Ubuntu desktop:
-Dcom.sun.management.jmxremote -Dcom.sun.management.jmxremote.port=9004 -Dcom.sun.management.jmxremote.authenticate=false -Dcom.sun.management.jmxremote.ssl=false

I have tried to connect to it using JConsole from a different machine on my network and I got the same error. I have tried to connect to the application using MX4J and I got the following exception:
java.rmi.ConnectException: Connection refused to host: 127.0.1.1; nested exception is:
java.net.ConnectException: Connection refused: connect
at sun.rmi.transport.tcp.TCPEndpoint.newSocket(TCPEndpoint.java:574)
at sun.rmi.transport.tcp.TCPChannel.createConnection(TCPChannel.java:185)
at sun.rmi.transport.tcp.TCPChannel.newConnection(TCPChannel.java:171)
at sun.rmi.server.UnicastRef.invoke(UnicastRef.java:94)
at javax.management.remote.rmi.RMIServerImpl_Stub.newClient(Unknown Source)
at javax.management.remote.rmi.RMIConnector.getConnection(RMIConnector.java:2239)
at javax.management.remote.rmi.RMIConnector.connect(RMIConnector.java:271)
at javax.management.remote.JMXConnectorFactory.connect(JMXConnectorFactory.java:248)
at org.mc4j.console.connection.JSR160ConnectionNode.connect(JSR160ConnectionNode.java:132)
at org.mc4j.console.connection.ReconnectAction.performAction(ReconnectAction.java:47)
at org.openide.util.actions.NodeAction$3.run(NodeAction.java:440)
at org.openide.util.actions.CallableSystemAction$ActionRunnable.actionPerformed(CallableSystemAction.java:247)
at org.netbeans.core.ModuleActions.invokeAction(ModuleActions.java:74)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:585)
at org.openide.util.actions.CallableSystemAction.invokeAction(CallableSystemAction.java:179)
at org.openide.util.actions.CallableSystemAction.access$000(CallableSystemAction.java:31)
at org.openide.util.actions.CallableSystemAction$ActionRunnable.doRun(CallableSystemAction.java:241)
at org.openide.util.actions.CallableSystemAction$2.run(CallableSystemAction.java:111)
at org.openide.util.Task.run(Task.java:136)
at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:330)
at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:686)
Caused by: java.net.ConnectException: Connection refused: connect
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:333)
at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:195)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:182)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:366)
at java.net.Socket.connect(Socket.java:520)
at java.net.Socket.connect(Socket.java:470)
at java.net.Socket.<init>(Socket.java:367)
at java.net.Socket.<init>(Socket.java:180)
at sun.rmi.transport.proxy.RMIDirectSocketFactory.createSocket(RMIDirectSocketFactory.java:22)
at sun.rmi.transport.proxy.RMIMasterSocketFactory.createSocket(RMIMasterSocketFactory.java:128)
at sun.rmi.transport.tcp.TCPEndpoint.newSocket(TCPEndpoint.java:569)
[catch] ... 23 more

I have noticed the Connection refused to host: 127.0.1.1. My /etc/hosts file (where the application is running) contains a line with the entry 127.0.1.1:
127.0.0.1 localhost
127.0.1.1 ubuntu-desktop


I removed the 127.0.1.1 line and I moved the host name to the end of the first line:
127.0.0.1 localhost ubuntu-desktop

After that I tried again to connect to my application using MX4J. This time I got the same exception but instead of 127.0.1.1 I got 127.0.0.1
 java.rmi.ConnectException: Connection refused to host: 127.0.0.1; nested exception is: java.net.ConnectException: Connection refused: connect
at sun.rmi.transport.tcp.TCPEndpoint.newSocket(TCPEndpoint.java:574)
at sun.rmi.transport.tcp.TCPChannel.createConnection(TCPChannel.java:185)
at sun.rmi.transport.tcp.TCPChannel.newConnection(TCPChannel.java:171)
at sun.rmi.server.UnicastRef.invoke(UnicastRef.java:94)
at javax.management.remote.rmi.RMIServerImpl_Stub.newClient(Unknown Source)
at javax.management.remote.rmi.RMIConnector.getConnection(RMIConnector.java:2239)
at javax.management.remote.rmi.RMIConnector.connect(RMIConnector.java:271)
at javax.management.remote.JMXConnectorFactory.connect(JMXConnectorFactory.java:248)
at org.mc4j.console.connection.JSR160ConnectionNode.connect(JSR160ConnectionNode.java:132)
at org.mc4j.console.connection.ReconnectAction.performAction(ReconnectAction.java:47)
at org.openide.util.actions.NodeAction$3.run(NodeAction.java:440)
at org.openide.util.actions.CallableSystemAction$ActionRunnable.actionPerformed(CallableSystemAction.java:247)
at org.netbeans.core.ModuleActions.invokeAction(ModuleActions.java:74)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:585)
at org.openide.util.actions.CallableSystemAction.invokeAction(CallableSystemAction.java:179)
at org.openide.util.actions.CallableSystemAction.access$000(CallableSystemAction.java:31)
at org.openide.util.actions.CallableSystemAction$ActionRunnable.doRun(CallableSystemAction.java:241)
at org.openide.util.actions.CallableSystemAction$2.run(CallableSystemAction.java:111)
at org.openide.util.Task.run(Task.java:136)
at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:330)
at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:686)
Caused by: java.net.ConnectException: Connection refused: connect
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:333)
at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:195)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:182)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:366)
at java.net.Socket.connect(Socket.java:520)
at java.net.Socket.connect(Socket.java:470)
at java.net.Socket.<init>(Socket.java:367)
at java.net.Socket.<init>(Socket.java:180)
at sun.rmi.transport.proxy.RMIDirectSocketFactory.createSocket(RMIDirectSocketFactory.java:22)
at sun.rmi.transport.proxy.RMIMasterSocketFactory.createSocket(RMIMasterSocketFactory.java:128)
at sun.rmi.transport.tcp.TCPEndpoint.newSocket(TCPEndpoint.java:569)
[catch] ... 23 more


After that I removed the host name from the file and I tried again, this time everything worked.

I have found this Blog entry about troubleshooting connection problems in jconsole. In my case the problem was different but it might be helpful to others .

2 comments:
gravatar
jkr said...
November 20, 2009 at 8:09 PM  

Thanks for the post, had similar problem. Found out that the issues around rmi host resolutions:
Step to resolve my particular issues:

- find out hostname of ubuntu server.
- make sure that hostname can be resolved from jconsole machine

Thanks for the pointer.
JK.

gravatar
Where is Darran? said...
October 18, 2011 at 7:38 PM  

thank you! this was my problem!

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