We have upgraded the Ambari Server and agent from 2.2.1.1 to 2.4.0.1-1 Ambari Server and Agent on the same server is running fine. We have additional 2 nodes and we are getting following error on both the nodes while starting Ambari agent. - we have updated ambari-agent.ini to point to Ambari Server - We do not see /var/log/ambari-agent/ambari-agent.log file created. - We have tried uninstall and re-install of the ambari-agent but still getting same following error. % ambari-agent restart --verbose Restarting ambari-agent Verifying Python version compatibility... Using python /usr/bin/python ambari-agent is not running. No PID found at /var/run/ambari-agent/ambari-agent.pid Verifying Python version compatibility... Using python /usr/bin/python Checking for previously running Ambari Agent... Starting ambari-agent Verifying ambari-agent process status... ERROR: ambari-agent start failed. For more details, see /var/log/ambari-agent/ambari-agent.out: ==================== from Controller import AGENT_AUTO_RESTART_EXIT_CODE File "/usr/lib/python2.6/site-packages/ambari_agent/Controller.py", line 37, in <module> import AmbariConfig File "/usr/lib/python2.6/site-packages/ambari_agent/AmbariConfig.py", line 26, in <module> from NetUtil import NetUtil File "/usr/lib/python2.6/site-packages/ambari_agent/NetUtil.py", line 22, in <module> from HeartbeatHandlers import HeartbeatStopHandlers File "/usr/lib/python2.6/site-packages/ambari_agent/HeartbeatHandlers.py", line 21, in <module> from ambari_commons.exceptions import FatalException ImportError: No module named ambari_commons.exceptions ==================== Agent out at: /var/log/ambari-agent/ambari-agent.out Agent log at: /var/log/ambari-agent/ambari-agent.log % yum info ambari-agent Loaded plugins: security Installed Packages Name : ambari-agent Arch : x86_64 Version : 2.4.0.1 Release : 1 Size : 38 M Repo : installed From repo : Updates-ambari-2.4.0.1 Summary : Ambari Agent URL : http://www.apache.org License : (c) Apache Software Foundation Description : Maven Recipe: RPM Package. ... View more