https://community.cloudera.com/t5/Support-Questions/Datanode-denied-communication-with-namenode/m-p/84658#M38866 <P>How was it fixed?</P> Tue, 08 Jan 2019 19:34:47 GMT don_pauly 2019-01-08T19:34:47Z https://community.cloudera.com/t5/Support-Questions/Datanode-denied-communication-with-namenode/m-p/69051#M38863 <P>Datanode unable to communicate with NameNode and getting following error message.&nbsp; I am using cloudera 5.14.0 version and i do not have DNS</P><P>&nbsp;</P><P>NN Static IP : 192.168.0.12 but it is trying other ip address 192.168.0.121</P><P>&nbsp;</P><P>Did anyone face this issue earlier.. I am unable to proceed further.</P><P>&nbsp;</P><P>Thanks in advance.</P><P>&nbsp;</P><P>Error message.</P><P>18-06-13 19:02:29,352 INFO org.apache.hadoop.hdfs.server.datanode.DataNode: Block pool BP-405258512-192.168.0.12-1528825240439 (Datanode Uuid 2bba9d98-a00c-40f0-9a0c-a479d071ba9f) service to cn3.hadoop.com/192.168.0.14:8022 beginning handshake with NN<BR />2018-06-13 19:02:29,716 ERROR org.apache.hadoop.hdfs.server.datanode.DataNode: Initialization failed for Block pool BP-405258512-192.168.0.12-1528825240439 (Datanode Uuid 2bba9d98-a00c-40f0-9a0c-a479d071ba9f) service to cn3.hadoop.com/192.168.0.14:8022 Datanode denied communication with namenode because hostname cannot be resolved (ip=192.168.0.121, hostname=192.168.0.121): DatanodeRegistration(192.168.0.12, datanodeUuid=2bba9d98-a00c-40f0-9a0c-a479d071ba9f, infoPort=50075, infoSecurePort=0, ipcPort=50020, storageInfo=lv=-56;cid=cluster8;nsid=762896661;c=0)</P> Fri, 16 Sep 2022 13:20:33 GMT https://community.cloudera.com/t5/Support-Questions/Datanode-denied-communication-with-namenode/m-p/69051#M38863 samkrish 2022-09-16T13:20:33Z https://community.cloudera.com/t5/Support-Questions/Datanode-denied-communication-with-namenode/m-p/69055#M38864 <P>I found following fix for Hadoop but&nbsp; I am not sure how to fix cloudera</P><P><SPAN>hdfs-site.xml - Need to add following line.</SPAN></P><P><SPAN class="hljs-tag">&lt;<SPAN class="hljs-title">property</SPAN>&gt;</SPAN> <SPAN class="hljs-tag">&lt;<SPAN class="hljs-title">name</SPAN>&gt;</SPAN><SPAN>dfs.namenode.datanode.registration.ip-hostname-check</SPAN><SPAN class="hljs-tag">&lt;/<SPAN class="hljs-title">name</SPAN>&gt;</SPAN> <SPAN class="hljs-tag">&lt;<SPAN class="hljs-title">value</SPAN>&gt;</SPAN><SPAN>false</SPAN><SPAN class="hljs-tag">&lt;/<SPAN class="hljs-title">value</SPAN>&gt;</SPAN> <SPAN class="hljs-tag">&lt;/<SPAN class="hljs-title">property</SPAN>&gt;</SPAN></P> Wed, 13 Jun 2018 14:56:04 GMT https://community.cloudera.com/t5/Support-Questions/Datanode-denied-communication-with-namenode/m-p/69055#M38864 samkrish 2018-06-13T14:56:04Z https://community.cloudera.com/t5/Support-Questions/Datanode-denied-communication-with-namenode/m-p/69244#M38865 <P>It is a bug in 5.14.0 .. at last&nbsp; I fixed it.</P> Wed, 20 Jun 2018 12:36:30 GMT https://community.cloudera.com/t5/Support-Questions/Datanode-denied-communication-with-namenode/m-p/69244#M38865 samkrish 2018-06-20T12:36:30Z https://community.cloudera.com/t5/Support-Questions/Datanode-denied-communication-with-namenode/m-p/84658#M38866 <P>How was it fixed?</P> Tue, 08 Jan 2019 19:34:47 GMT https://community.cloudera.com/t5/Support-Questions/Datanode-denied-communication-with-namenode/m-p/84658#M38866 don_pauly 2019-01-08T19:34:47Z