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AppDynamics Team



A legacy Machine Agent and Java Application Agent are installed on a machine. Despite correct installation and configuration, one or both of the Agents do not report. The first step in troubleshooting this issue is to validate the Unique Host ID, which is a problem more common with Machine Agents.


Machine Agents use the Java API to get the Unique Host ID. Sometimes the same JVM can return different values for the same machine each time the Machine Agent is restarted. One possible cause is the Unique Host ID of the App Agent and the Machine Agent are not in sync. In this case, the Machine Agent does not know which application to register.





  1. Search for the application or the Unique Host ID on both the Application and Machine Agents, and make sure that the values are the same.
    • Examples: 
  2. To confirm the issue, go to the Agent settings page located at either of the following URLs: 
    •  http://<host:Port>/controller/#/location=SETTINGS_AGENTS
    • http://<host:Port>/#/location=SETTINGS_MACHINE_AGENTS
    • Screen Shot 2017-06-28 at 4.58.26 PM.pngScreen Shot 2017-06-28 at 4.58.38 PM.png
  3.  Also, verify that the Machine Agent is associated with the application. 





If there is any discrepancy between the two Agents, resolve the issue by providing the same Unique Host ID value for the App Agent and the Machine Agent using the following steps.


Note: If it is not feasible to stop the App agent, it is possible to sync the Unique Host ID value of the Machine Agent with the App Agent, and then apply the property to the App Agent on the next restart.


  1. Stop both Agents.
  2. Start the App Agent with the following property:
    • -Dappdynamics.agent.uniqueHostId=<your-host-id> system property
  3. Confirm that there are no new errors or issues with the App Agent.
  4. Start the Machine Agent with the same property:
    • -Dappdynamics.agent.uniqueHostId=<your-host-id> system property
    • Another option is to add a <unique-host-id>your-host-id</unique-host-id> element within the <machine_agent_install>/conf/controller-info.xml file.

ok i wound up deleting the app in appd controller and re-creating it with the settings and then that worked - thanks

AppDynamics Team (Retired)

@James.Pace , thank you for sharing what worked for you.

Claudia Landivar
Community Manager & Editor

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Last update:
‎06-28-2017 10:20 AM
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