We're federating a secure HDFS cluster with an insecure cluster.
Using HDFS RPC, we can access the data managed by insecure Namenode and stored in secure Datanode.
However, it does not work for WebHDFS due to HadoopIllegalArgumentException.
This is because secure Datanode expects a delegation token, but insecure Namenode does not return it to a client.
The issue proposes to support the access also for WebHDFS.
The attached PDF file webhdfs-federation.pdf depicts our current architecture and proposal.