Dear all,   Version: Cloudera Express 5.14.2 1 master nodes 7 workers   Problem: "The health test result for DATA_NODE_WEB_METRIC_COLLECTION has become bad: The Cloudera Manager Agent is not able to communicate with this role's web server." When above alert pops up such record were noticed in datanode logs: ERROR DataNode BlockSender.sendChunks() exception: java.io.IOException: Broken pipe at sun.nio.ch.FileChannelImpl.transferTo0(Native Method) at sun.nio.ch.FileChannelImpl.transferToDirectlyInternal(FileChannelImpl.java:428) at sun.nio.ch.FileChannelImpl.transferToDirectly(FileChannelImpl.java:493) at sun.nio.ch.FileChannelImpl.transferTo(FileChannelImpl.java:608) at org.apache.hadoop.net.SocketOutputStream.transferToFully(SocketOutputStream.java:223) at org.apache.hadoop.hdfs.server.datanode.BlockSender.sendPacket(BlockSender.java:605) at org.apache.hadoop.hdfs.server.datanode.BlockSender.doSendBlock(BlockSender.java:789) at org.apache.hadoop.hdfs.server.datanode.BlockSender.sendBlock(BlockSender.java:736) at org.apache.hadoop.hdfs.server.datanode.DataXceiver.readBlock(DataXceiver.java:551) at org.apache.hadoop.hdfs.protocol.datatransfer.Receiver.opReadBlock(Receiver.java:148) at org.apache.hadoop.hdfs.protocol.datatransfer.Receiver.processOp(Receiver.java:103) at org.apache.hadoop.hdfs.server.datanode.DataXceiver.run(DataXceiver.java:246) at java.lang.Thread.run(Thread.java:748) cloudera-scm-agent logs: 2158 Monitor-GenericMonitor throttling_logger ERROR (8 skipped) Error fetching metrics at 'http://datanode02.hadoop:1006/jmx' Traceback (most recent call last): File "/usr/lib64/cmf/agent/build/env/lib/python2.7/site-packages/cmf-5.14.2-py2.7.egg/cmf/monitor/generic/metric_collectors.py", line 203, in _collect_and_parse_and_return simplejson.load(opened_url)) File "/usr/lib64/cmf/agent/build/env/lib/python2.7/site-packages/simplejson-2.1.2-py2.7-linux-x86_64.egg/simplejson/__init__.py", line 324, in load return loads(fp.read(), File "/usr/lib64/python2.7/socket.py", line 351, in read data = self._sock.recv(rbufsize) File "/usr/lib64/python2.7/httplib.py", line 602, in read s = self.fp.read(amt) File "/usr/lib64/python2.7/socket.py", line 380, in read data = self._sock.recv(left) timeout: timed out Alerts are throwing from specific datanodes, not from all.   What can be the problem here?   Thanks in advance Panjl ... View more