This host-level alert is triggered if the individual DataNode processes cannot be
established to be up and listening on the network for the configured critical threshold,
given in seconds. It uses the Nagios check_tcp plugin.
DataNode process is down or not responding
DataNode are not down but is not listening to the correct network port/address
Nagios server cannot connect to the DataNodes
Check for dead DataNodes in Ambari Web.
Check for any errors in the DataNode logs (
/var/log/hadoop/hdfs) and restart the DataNode, if necessaryRun the
netstat-tuplpncommand to check if the DataNode process is bound to the correct network portUse
pingto check the network connection between the Nagios server and the DataNode
