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Troubleshooting Agent Issues - FAQs

Contents:

 

Q. Is there a way to delete an abandoned Machine Agent when it is not attached to any APM agents? 

 

A. Yes, there are two ways to delete the abandoned machine agent, either from controller UI by creating a dummy application or through a manual step to delete the agent from the database. The steps for both are located here: Delete abandoned machine agent.

 

 

 

Q. What is the best way to set up alerts for App Agent Status and Machine Agent Status? 

 

A. There are two solutions for this, found here: Agent Status on .NET 

 

 

 

Q. What does the error message "account key doesn't match with the current account for machine id" mean?

 

A. The message indicates that account key generated by AppDynamics controller during the registration may be changed at this point in time. This could happen if you migrate the Controller without shutting down the agents. Restart the agent to resolve this error.

 

 

 

Q. How to resolve Agent causing overhead or crash.

 

A. Follow these steps to troubleshoot:

  1. Check the agent logs for any communication errors between Agent and Controller.
  2. Make sure ALD has not been turned on for a long time.
  3. The Agent requires 30 MB of permgen space. Set this parameter (-XX:MaxPermSize=<value>) to a higher value (256m at least) and try again.
  4. Get the crash report and heap dump for analysis.
  5. Check the agent log level is set to INFO (default log level value if not changed to debug/trace) at agent_dir/conf/logging/log4j.xml.
  6. Make sure periodic sampling and occurrence request sampling is not set to a low value (default 100 requests and 10 min, update/disable as per requirement).
  7. Check the agent logs if any repetitive exceptions are logged.
  8. Disable the agent from the node dashboard and monitor the heap usage whether the overhead/crash is still happening to find whether agent/webapp instrumentation
    is raising the issue.

 

 

Q. When requesting agent logs in <Application> -> Servers -> App Servers -> <tier> -> <node> -> Agents, the log status times out. One possible cause is someone first requested the log and reset the agent before the log sends to the Controller.

 

A. Reset agent before requesting the agent log.

   

 

 

Q. Is it possible to assign a Machine Agent to multiple applications on the same server?

 

A. We need to run one machine agent process for each application on a machine.

  • Add the VM parameter (-Dappdynamics.agent.uniqueHostId=<<some unique value per application>>) to both Machine Agent and the App Agent. Provide the same value to the machine - app agent pair.
  • For example, if you have 2 nodes (n1 and n2 ) reporting to applications (a1 and a2). Let's say m1 and m2 are your machine agents for the corresponding nodes. You will need to pass -Dappdynamics.agent.uniqueHostId=a1 for n1 and m1. and -Dappdynamics.agent.uniqueHostId=a2 for n2 and m2.
  • The uniqueHostId value can be any unique value but should be different for each application.
  • After restarting the JVMs with the above options you should see machine agents associating with corresponding applications. 

 

 

Q. I want to get the list of AppD agents. I mean, we can see those list of agents in settings, but I want to get all of those agents to an Excel sheet. Is there any way that we can export the list of agents and details? 

 

A. It's not out of the box, but there is a workaround.

  1. Create small program which can read /controller/rest/applications - List of all applications and get list of nodes from /controller/rest/applications/<application-name|application-id>/nodes
  2. Go to AppDynamics Agents page. Take screenshot. Trim the picture. Copy it to One Note. Right-click and Copy to Text.

 

More Troubleshooting Guides:

 

Published 2/26/2018

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Revision #:
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Last update:
‎09-10-2018 11:46 AM
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