[Hadoop] How to troubleshoot Ambari Server error that is related to SSL that occurred on the server while adding new Ambari hosts.

[Hadoop]

While adding new Ambari host using automated Install, the following error occurred on the Ambari Server:

	INFO 2020-02-11 13:35:08,456 NetUtil.py:60 - Connecting to https://SERVERHOSTNMAE.MYDOMAIN:8440/ca
	ERROR 2020-02-11 13:35:08,653 NetUtil.py:84 - [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:618)
	ERROR 2020-02-11 13:35:08,653 NetUtil.py:85 - SSLError: Failed to connect. Please check openssl library versions.
	Refer to: https://bugzilla.redhat.com/show_bug.cgi?id=1022468 for more details.
	WARNING 2020-02-11 13:35:08,655 NetUtil.py:112 - Server at https://SERVERHOSTNMAE.MYDOMAIN:8440 is not reachable, sleeping for 10 seconds...

	Registration with the server failed. 

I tried to solve the error through several sites, but failed repeatedly.
But finally, I solved the problem through the following site: 

https://stackoverflow.com/questions/51601391/ambari-agent-no-longer-able-to-contact-server-at-http-dom8440

 

Resolution process:

First, make sure that the service that can install the Ambari Agent is running.

[Ambari Server]
# netstat -tapn | grep 8440

tcp6       0      0 :::8440                 :::*                    LISTEN      2159/java 

If the service is running, check or modify the following:

[Ambari Agent]
　/etc/ambari-agent/conf/ambari-agent.ini

     [security]
     ssl_verify_cert = 0 

 

　/etc/python/cert-verification.cfg

     [https]
     #verify=platform_default
     verify=disable 

After that, the agent service restart.

# ambari-agent restart