When attempting to restart the Agent, you may encounter this error:

Error: Another program is already listening on a port that one of our HTTP servers is configured to use. Shut this program down first before starting supervisord.

This indicates that the Agent did not shut down correctly.

To resolve this issue, take the following steps:

1. Stop the Agent:

   sudo /etc/init.d/datadog-agent stop
   

2. Confirm that there are no processes running for the user dd-agent after stopping:

   top -U dd-agent
   

   Kill any processes running under dd-agent, if you find any.

3. Start the Agent again.

   sudo /etc/init.d/datadog-agent start
   

If this doesn’t solve your issue, reach out to Datadog Support.

Additional helpful documentation, links, and articles:

Learn more about the Datadog AgentDOCUMENTATION