https://community.cloudera.com/t5/Support-Questions/DATA-NODE-was-removed-from-Ambari-Due-to-Rackwareness/m-p/206917#M168878 <P>Good Morning Experts, </P><P>I am currently facing the following issue: </P><P>We have 200 nodes hadoop cluster and we configured rack awareness, suddenly we noticed one of the datanode was missing from Ambari, but we do have that datanode process on that particular node, when we looked at the logs, we have noticed the following error: </P><P><STRONG></STRONG></P><P>I<STRONG>nitialization failed for Block pool BP-3x84848-92929299 (Datanode Uuid 6048438486-d001-47af-a899-6493aca15c4c) service to hostname.com/&lt;data node ip&gt;:8020 Failed to add /default-rack/&lt;datanode ip&gt;:1019: You cannot have a rack and a non-rack node at the same level of the network topology.</STRONG></P><P>We have added the datanode again from ambari, but after starting the datanode, but it is still complaining with the above errors in the datanode logs. I didn't see any similar question in the community, so i am looking for your help. </P><P>Since this is currently an issue in our production cluster, can anyone please help me quickly? </P><P>I greatly appreciate your quick help.</P><P>thanks,</P><P>~hdpadmin </P> Fri, 21 Apr 2017 02:24:33 GMT ssanupindi 2017-04-21T02:24:33Z