JMeter server doesn't alert the user when the host is defined as a loopback address

[asfimport]

Rubén Laguna (Bug 41028):
Due to Sun Bug 4665037
(http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4665037) rmi in linux may
not work if the name resolution is not properly configured.

The problem is that under linux the jmeter server in rmi will be bound to ip
127.0.0.1 instead of the real (externally reachable) ip address of the machine.
So although the jmeter master will be able to locate the "JMeterEngine"
instances via the RMI registry. It will not be able to connect to the actual
instances.

Actually JMeter will not complain when this happens it doesn't tell you anything
when launching jmeter-server ( not even in logs) and it will silently fail when
trying to start the remote instances (no trace in the logs).

It's very easy to include a check in RemoteJMeterEngineImpl.java to check
InetAddress.getLocalHost().isLoopbackAddress() and raise an exception or at
least log it.

Also it would be very convenient to add log statements in the catch
java.rmi.xxxxException blocks in the ClientJMeterEngine.java.

} catch (java.rmi.ConnectException e) {
log.error("rmi exception", e);

because otherwise this kind of failures go unnoticed.

Severity: trivial
OS: Linux

[asfimport]

Rubén Laguna (migrated from Bugzilla):
This patch detects if the the address we are binding to the rmiregistry is a
loopback address and throws an exception if this is the case.

Created attachment RemoteJMeterEngineImpl.patch: Path to detect if the system is trying to register a loopback address to the rmi registry

RemoteJMeterEngineImpl.patch

Index: src/core/org/apache/jmeter/engine/RemoteJMeterEngineImpl.java
===================================================================
--- src/core/org/apache/jmeter/engine/RemoteJMeterEngineImpl.java	(revision 479800)
+++ src/core/org/apache/jmeter/engine/RemoteJMeterEngineImpl.java	(working copy)
@@ -51,13 +51,19 @@
 		log.debug("This = " + this);
 		try {
 			Registry reg = LocateRegistry.getRegistry(port);
-			backingEngine = new StandardJMeterEngine(InetAddress.getLocalHost().getHostName());
+			final InetAddress localHost = java.net.InetAddress.getLocalHost();
+			if (localHost.isLoopbackAddress()) {
+				throw new RuntimeException("java.net.InetAddress.getLocalHost() returned a loopback address, we can bind to the registry but the server will not be accessible. If you are running on linux check sun bug id (http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4665037) for solutions to this problem");
+			}
+			final String hostName = localHost.getHostName();
+			backingEngine = new StandardJMeterEngine(hostName);
+			log.info("this: " + this);
 			reg.rebind("JMeterEngine", this); // $NON-NLS-1$
-			log.info("Bound to registry on port " + port);
+			log.info("Bound to registry on port " + port + " with hostname " + hostName);
 		} catch (Exception ex) {
-			log.error("rmiregistry needs to be running to start JMeter in server " + "mode\n\t" + ex.toString());
+			log.error("rmiregistry needs to be running to start JMeter in server " + "mode\n\t", ex);
 			// Throw an Exception to ensure caller knows ...
-			throw new RemoteException("Cannot start. See server log file.");
+			throw new RemoteException("Cannot start. See server log file.",ex);
 		}
 	}
 

[asfimport]

Sebb (migrated from Bugzilla):
Thanks for the patch.

Implemented in SVN r604072.