JMX error fetching data

[rokcarl (Rok)]

I'm trying to send JMX data using a Dockerized Metricbeat to the cloud, but I get the following error:

2019-08-30T09:30:45.033Z	INFO	module/wrapper.go:247	Error fetching data for metricset jolokia.jmx: error making http request: Post http://localhost:9998/jolokia: EOF

Here's some of my config:

- module: jolokia
  metricsets: ["jmx"]
  period: 1s
  hosts: ["localhost:9998"]
  namespace: "metrics"
  jmx.mappings:
    - mbean: 'java.lang:type=Runtime'
      attributes:
        - attr: Uptime
          field: uptime
          event: uptime
    - mbean: 'java.lang:type=GarbageCollector,name=ConcurrentMarkSweep'
      attributes:
        - attr: CollectionTime
          field: gc.cms_collection_time
        - attr: CollectionCount
          field: gc.cms_collection_count
    - mbean: 'java.lang:type=Memory'
      attributes:
        - attr: HeapMemoryUsage
          field: memory.heap_usage
        - attr: NonHeapMemoryUsage
          field: memory.non_heap_usage

I'm running my Java application with the following options:

-Dcom.sun.management.jmxremote -Dcom.sun.management.jmxremote.local.only=true -Dcom.sun.management.jmxremote.authenticate=false -Dcom.sun.management.jmxremote.ssl=false -Dcom.sun.management.jmxremote.rmi.port=9998 -Dcom.sun.management.jmxremote.port=9998

I hope the above satisfies the requirement from the Elastic JMX docs for the JMX agent through JVM.

I've verified that I can connect and see metrics by running the jmxterm tool:

java -jar jmxterm-1.0.1-uber.jar -l localhost:9998
Welcome to JMX terminal. Type "help" for available commands.
$>beans
#domain = JMImplementation:
JMImplementation:type=MBeanServerDelegate
#domain = com.sun.management:
com.sun.management:type=DiagnosticCommand
com.sun.management:type=HotSpotDiagnostic
#domain = io.dropwizard:
io.dropwizard:type=Logging
#domain = java.lang:
java.lang:name=CodeCacheManager,type=MemoryManager
java.lang:name=CodeHeap 'non-nmethods',type=MemoryPool
java.lang:name=CodeHeap 'non-profiled nmethods',type=MemoryPool
...

Any ideas why this is happening?

[rokcarl (Rok)]

I was using the JVM flags, but apparently that's not a Jolokia agent.
Installing that as a separate JAR file fixed things.