There are 1 datanode(s) running and 1 node(s) are excluded in this operation.

[#1]

FileSystem Operation Failed: File /tmp/xxx.txt could only be written to 0 of the 1 minReplication nodes. There are 1 datanode(s) running and 1 node(s) are excluded in this operation.

I'm using Cloudera Trial version installed in single node. Does anyone have this problem too?

[#2]

Particular datanode has been excluded from write operation. Why excluded ? Need to check the namenode log and datanode log. You can share the logs to debug further. Also check then namenode UI and Datanodes link for errors.