We need to make sure below point in heart beat lost host. check firewall status. It should be stop. service iptables stop check /etc/ambari-agent/conf/ambari-agent.ini file. in ambari-agent file hostname entry should be hostname = ambariservernodehost ambariservernodehost should be present in /etc/hosts file openssl version should be upgraded. Stop ambari-server Stop ambari-agent service on all nodes Start ambari-agent service on all nodes Start ambari-server server check logs of ambari agent. If even there is problem then please reply me. ... View more