Connection failed to http://sandbox-hdp.hortonworks.com:8042/ws/v1/node/info (Traceback (most recent call last): File "/var/lib/ambari-agent/cache/common-services/YARN/2.1.0.2.0/package/alerts/alert_nodemanager_health.py", line 171, in execute url_response = urllib2.urlopen(query, timeout=connection_timeout) File "/usr/lib64/python2.7/urllib2.py", line 154, in urlopen return opener.open(url, data, timeout) File "/usr/lib64/python2.7/urllib2.py", line 431, in open response = self._open(req, data) File "/usr/lib64/python2.7/urllib2.py", line 449, in _open '_open', req) File "/usr/lib64/python2.7/urllib2.py", line 409, in _call_chain result = func(*args) File "/usr/lib64/python2.7/urllib2.py", line 1244, in http_open return self.do_open(httplib.HTTPConnection, req) File "/usr/lib64/python2.7/urllib2.py", line 1214, in do_open raise URLError(err) URLError: <urlopen error [Errno 111] Connection refused> ) Nodemanager has above error Also there's another error: Percent NodeManager Available This alert is triggered if the number of down NodeManagers in the cluster is greater than the configured critical threshold. It aggregates the results of NodeManager process checks. I use Ambari 2.6.2.0. By the way, I'm using HDP sandbox via docker on my CentOS 7 Server. It's the first startup of the container but already giving those errors Thank you for your response, hkumar ... View more