We have a cluster based on HDP 2.6.4. We added news nodes that are now systematically installed under centos 7.6 version. In that configuration, ambari-agent can not connect to the server and raises the following error in ambari-agent.log:
To solve this problem simply configure the Ambari Agent to use TLSv1.2 when communicating with the Ambari Server by editing each Ambari Agent’s /etc/ambari-agent/conf/ambari-agent.ini file and adding the following configuration property to the security section:
Once this configuration change has been made, the Ambari Agent needs to be restarted. After restarting you should no longer see the ERROR’s in the Ambari Agent logs, and in the Ambari Server UI you’ll notice that all Ambari Agents are once again heartbeating.