Why is the Machine Agent not reporting properly?

[#1]

Users who are troubleshooting scenarios where the AppDynamics Standalone Machine Agent is not reporting metrics as expected will find causes and solutions here. The following solutions apply to versions 4.4 and higher.

Contents:

• Installation issues

• Host ID for App Server Agent and Machine Agent do not match

• Difficulty with machine hostname resolution

• Machine Agent reporting all metrics as zero

Problem: Installation issues

If both an App Server Agent and the Machine Agent are unzipped into the same directory, important files will be overwritten, such as the log4j.xml file.

Solution:

When unzipping the App Agent or Machine Agent zip files, make sure to use different directories.

Problem: Host ID for App Server Agent and Machine Agent do not match 

Both the App Server Agent and the Machine Agent use the Java API to get the host ID. The results from the API can be inconsistent and the same JVM can sometimes return a different value for the same machine each time the Machine Agent is restarted. 

When the host ID is then registered with the Controller the app server agent and the machine agent can be assigned different host IDs even though they are running on the same machine.

Solution:

Reset the hostname for the Machine Agent by running the agent with the

-Dappdynamics.agent.uniqueHostId JVM parameter. Set the host ID to be the same as the one the App Server Agent is using. 

Problem: Difficulty with machine hostname resolution

If the following error is seen in the Machine Agent log file, the cause is hostname resolution, which affects Machine Agent startup and registration.

.ERROR XMLConfigManager - Error in Default Host Identifier Resolver resolving host name
java.net.UnknownHostException: log-aggregate01: log-aggregate01

Solution:

1. Verify a valid hostname in the /etc/hosts file.

• Example:

localhost    log-aggregate01
127.0.0.1         log-aggregate01

2. Save the changes.
3. Restart the Machine Agent.

Problem: Machine Agent reporting all metrics as zero

You have verified in the Machine Agent log that the Machine Agent is only collecting zero-values. 

Solution:

1. Change permissions on the Machine Agent installation folder for the user ID that the Machine Agent was started under chmod -R 777 <machine-agent-install>.

2. Restart the Machine Agent and verify that the zero values are no longer being reported.

3. If restarting does not help, disable Sigar Hardware monitoring located in the JavaHardwareMonitoring directory.

• In the monitor.xml file (located at: <machine-agent-install>/monitors/JavaHardwareMonitor/*), change the enabled property to false.

  Example:

  <monitor> <name>SigarHardwareMonitor</name> 
  <type>managed</type> 
  <enabled>true</enabled> ---> change this to false –> <enabled>false</enabled>

4. Enable OS-specific hardware monitoring found in the HardwareMonitoring directory. 

• In monitor.xml file (location: <machine-agent-install>/monitors/HardwareMonitor/*) 
  

  <monitor> 
  <name>HardwareMonitor</name> 
  <type>managed</type> 
  <enabled>false</enabled> ---> change this to true –> <enabled>true</enabled>

5. Restart the Machine Agent and verify that the zero values are no longer being reported.

Last Updated 3/28/19

[John.Aronson]

I'm seeing mixed messages about the default machine agent metric limit in newer versions. I think it's 450 in version 4.2.4 and latrer. Can this be clarified?

[Doug.Bothwell]

Hi john.aronson, I've updated this article to clarify that the default maximum limit for Standalone machine Agents in 4.2.4 and higher. Are there other areas where you're seeing mixed messages? I updated the product 4.2, 4.3, and 4.4 docs a few weeks ago to ensure this default max is correct. 

[Erin]

I have updated this article to remove the old outdated information and keep everything applicable to 4.4 and higher.