On 7/22/16 8:45 AM, Kun Ren wrote:
(1). How to create/start multiple namenodes?
Just pretend like you have two separate HDFS clusters and set them up that way. (That is actually what you have.)
(2). Once I have multiple Namenodes running, do you think what is the best/simple way to change the HDFS client code to let the clients send the requests to a random Namenode?
The client code is already built to try multiple NNs to handle HA. You can look there for inspiration. If you want random, grab a random number and mod it by the number of NNs, then use that as an index into the list of NNs.
(3). I need to support the communication between the Namenodes, my current plan is to create one more protocol that supports the communication between the Namenodes, something like the clientProtocol and ClientDataNodeProtocol. Do you think is it easy to do so? Or do you have other suggestions to support the communication between the Namenodes?
You will indeed need to define a new protocol. Not the easiest thing in the world, but there are plenty of docs on protobuf. Good luck!
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