ActiveMQ 5.8 network of broker with custom jmx port - activemq

Question

I am trying to run a network of broker with 2 brokers on the same network but on 2 different virtual machines.
Because of some internal constraints I have to use a custom jmx port.
I am using the Tanuki wrapper to launch ActiveMQ on an Ubuntu server.
Here is the relevant part of my activemq.xml
<broker xmlns="http://activemq.apache.org/schema/core" advisorySupport="false" useJmx="true" brokerName="test1" dataDirectory=".../data/activemq">
<networkConnectors>
<networkConnector uri="multicast://1.2.3.4:101234?group=test"
dynamicOnly="true"
networkTTL="3"
prefetchSize="1"
decreaseNetworkConsumerPriority="true"
userName="user"
password="password"/>
</networkConnectors>
<transportConnectors>
<transportConnector name="openwire" uri="tcp://0.0.0.0:61616" rebalanceClusterClients="true" updateClusterClients="true" />
<transportConnector name="nio" uri="nio://0.0.0.0:61617" rebalanceClusterClients="true" updateClusterClients="true" discoveryUri="multicast://1.2.3.4:101234?group=test" />
</transportConnectors>
...
<managementContext>
<managementContext createConnector="false"/>
</managementContext>
...
</broker>
Here is the relevant part of wrapper.conf:
# Uncomment to enable jmx
wrapper.java.additional.1=-Dcom.sun.management.jmxremote
wrapper.java.additional.2=-Dcom.sun.management.jmxremote.port=4321
wrapper.java.additional.3=-Dcom.sun.management.jmxremote.authenticate=false
wrapper.java.additional.4=-Dcom.sun.management.jmxremote.ssl=false
When running ActiveMQ on both broker, I see the process with the expected options:
activemq 30682 30680 3 13:27 ? 00:00:30 java -Dcom.sun.management.jmxremote -Dcom.sun.management.jmxremote.port=4321 -Dcom.sun.management.jmxremote.authenticate=false -Dcom.sun.management.jmxremote.ssl=false -Djavax.net.ssl.keyStore=../../conf/broker.ks -Djavax.net.ssl.trustStore=../../conf/broker.ts -Dcom.sun.management.jmxremote -Dorg.apache.activemq.UseDedicatedTaskRunner=true -Djava.util.logging.config.file=logging.properties -Dactivemq.conf=../../conf -Dactivemq.data=../../data -Xms2048m -Xmx2048m -Djava.library.path=../../bin/linux-x86-64/ -classpath ../../bin/wrapper.jar:../../bin/activemq.jar -Dwrapper.key=y4TuwO32Hj6kN7w8 -Dwrapper.port=32000 -Dwrapper.jvm.port.min=31000 -Dwrapper.jvm.port.max=31999 -Dwrapper.pid=30680 -Dwrapper.version=3.2.3 -Dwrapper.native_library=wrapper -Dwrapper.service=TRUE -Dwrapper.cpu.timeout=10 -Dwrapper.jvmid=1 org.tanukisoftware.wrapper.WrapperSimpleApp org.apache.activemq.console.Main start
The port is open on the running shorewall.
The network of broker is up but I cannot connect to the jmx using jvisualvm with server_dns:4321. It returns the error
"cannot connect to server_dns:4321 using service:jmx:rmi:///jndi/rmi://server_dns:4321/jmxrmi
I can see some traffic on the port via tcpdump.
Could anybody tell me what I am doing wrong or how I should use ActiveMQ as a Network Of Broker with a custom jmx port?

Answer 1

JMX needs 2 open ports. An extra one is necessary for rmi.
I figured it out thanks to this post: Apache ActiveMQ browser can't connect to JMX console
In my case the fix is to change the configuration of my wrapper to expose the rmi port and open the port on the firewall
# Uncomment to enable jmx
wrapper.java.additional.1=-Dcom.sun.management.jmxremote
wrapper.java.additional.2=-Dcom.sun.management.jmxremote.port=4321
wrapper.java.additional.3=-Dcom.sun.management.jmxremote.port=8765
wrapper.java.additional.4=-Dcom.sun.management.jmxremote.authenticate=false
wrapper.java.additional.5=-Dcom.sun.management.jmxremote.ssl=false