Hi, I would like to know the following. 1) Can there be multiple namespaces in a single namenode? is it recommended? (I'm having a multi-tenant environment in mind)
2) Let's say I have a federated namespace/namenodes. There are two namenodes A /namespace A1 and namenode B/namespace B1, and have 3 datanodes. Can someone from namespace A1, access the datanode's data in anyway (hacking) belonging to namespace B1. If not how is it handled? After going through a lot of reference, my understanding on HDFS multi-tenancy and federation is that for multi-tenancy what we could do is use file/folder permissions (u,g,o) and ACL's. Or we could dedicate a namespace per tenant. The issue here is that a namenode (active namenode, passive namenode and secondary namenode) has to be assigned per tenant. Is there any other way that multi tenancy can be achieved? On federation, let's say I have a namenode for /marketing and another for /finance. Lets say that marketing bears the most load. How can we load balance this? is it possible? Appreciate any help on this. Regards, Shani.
