I tried to add another host via cloudera manager .
I followed the below steps
1. Hosts - > Add hosts -> provided the ip address -> CM asked me to create a host template but i gave none and finised .
2. Found the host in good health .
3. Cluster -> HDFS -> Instances -> Add -> I added a Datanode with the new hosts.
(Now the Datanode i added was not starting , When i search for logs via UI i dont find any . I searched for logs in logs/datanode folder , but there was no Datanode folder in Var .)
4. Cluster -> Deploy client Configuration -> Completed -> Still the Datanode was not starting .
Please help .
Issue resolved . I added hosts by stopping the Datanodes agent first and then proceeded . After adding the hosts i started the agent . It worked :).
I too face the same issue. Can you please elaborate on "delete the local data dir(s)" in the below comments.
Data directory is local filesystem storage location for each datanode in your cluster. Search for "dfs.datanode.data.dir" property in hdfs-site.xml file to find out. You can also search in cloudera configuration search tab of your datanode.