How to solve the issue of ambari-agent cannot register ambari-server with error NetUtil.py:85 – SSLError: Failed to connect…

1. On Ambari Server “/etc/amabri-server/conf/ambari.properties” file add the following protocols:

security.server.disabled.protocols=SSL|SSLv2|SSLv2Hello|SSLv3|TLSv1

then restart ambari-server by: systemctl restart ambari-server

2. Add the following option to security section in “/etc/amabri-agent/conf/ambari-agent.ini” in all the hosts in the cluster

[security]
force_https_protocol=PROTOCOL_TLSv1_2

and restart ambari-agent by: systemctl restart ambari-agent

(Reference: https://community.hortonworks.com/questions/114808/ambari-agents-cannot-reach-ambari-server-after-cha.html)