title: ambari-agent no longer able to contact server at http://<dom>:8440?
body: <p>We're currently running Hortonworks 2.6.5.0:</p>
  
  <pre><code>$ hadoop version
  Hadoop 2.7.3.2.6.5.0-292
  Subversion git@github.com:hortonworks/hadoop.git -r 3091053c59a62c82d82c9f778c48bde5ef0a89a1
  Compiled by jenkins on 2018-05-11T07:53Z
  Compiled with protoc 2.5.0
  From source with checksum abed71da5bc89062f6f6711179f2058
  This command was run using /usr/hdp/2.6.5.0-292/hadoop/hadoop-common-2.7.3.2.6.5.0-292.jar
  </code></pre>
  
  <p>The OS is CentOS 7:</p>
  
  <pre><code>$ cat /etc/redhat-release
  CentOS Linux release 7.5.1804 (Core)
  </code></pre>
  
  <p>We recently started noticing these issues in the <code>ambari-agent</code>'s log file:</p>
  
  <pre><code>$ grep -i "error|warn" /var/log/ambari-agent/*
  /var/log/ambari-agent/ambari-agent.log:WARNING 2018-07-30 14:03:50,982 NetUtil.py:124 - Server at https://hbase26-2.mydom.com:8440 is not reachable, sleeping for 10 seconds...
  /var/log/ambari-agent/ambari-agent.log:ERROR 2018-07-30 14:04:00,986 NetUtil.py:96 - EOF occurred in violation of protocol (_ssl.c:579)
  /var/log/ambari-agent/ambari-agent.log:ERROR 2018-07-30 14:04:00,990 NetUtil.py:97 - SSLError: Failed to connect. Please check openssl library versions.
  /var/log/ambari-agent/ambari-agent.log:WARNING 2018-07-30 14:04:00,990 NetUtil.py:124 - Server at https://hbase26-2.aa.mydom.com:8440 is not reachable, sleeping for 10 seconds...
  /var/log/ambari-agent/ambari-agent.log:ERROR 2018-07-30 14:04:10,993 NetUtil.py:96 - EOF occurred in violation of protocol (_ssl.c:579)
  /var/log/ambari-agent/ambari-agent.log:ERROR 2018-07-30 14:04:10,994 NetUtil.py:97 - SSLError: Failed to connect. Please check openssl library versions.
  /var/log/ambari-agent/ambari-agent.log:WARNING 2018-07-30 14:04:10,994 NetUtil.py:124 - Server at https://hbase26-2.aa.mydom.com:8440 is not reachable, sleeping for 10 seconds...
  /var/log/ambari-agent/ambari-agent.log:ERROR 2018-07-30 14:04:20,996 NetUtil.py:96 - EOF occurred in violation of protocol (_ssl.c:579)
  /var/log/ambari-agent/ambari-agent.log:ERROR 2018-07-30 14:04:20,997 NetUtil.py:97 - SSLError: Failed to connect. Please check openssl library versions.
  </code></pre>
  
  <p>When these started occurring we could no longer manage any aspects of the Hadoop cluster through Ambari. All the services showed little yellow question marks and said "heartbeat lost".</p>
  
  <p>Multiple restarts would not allow us to resume Ambari, and ultimately regain control our cluster.</p>