What is the Hostname when using Apache NiFi in Cloudera for ListenHTTP/HandleHTTPRequest processors?

@carlosst Welcome to the Cloudera Community!

To help you get the best possible solution, I have tagged our NiFi experts @SAMSAL @MattWho  who may be able to assist you further.

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Hi,

I dont think there is hostname property under ListenHttp and if there was at some point it probably got removed later on.  Regarding the hostname under HandleHttpRequest, its basically to specify which node you would like to receive the request on in case of cluster. If you specify certain node it will only allow connection to that node only however if you leave it empty  as the description says it will bind to all which mean you can send request using any node host name.

Hope that helps.

@carlosst 

With a NiFi cluster, each node runs its ow copy of the flow.json.gz into memory on startup.
As such processors like listeners will when started create a listener on each node.

http://{NiFi node hostname}:{port}/contentListener

There is no property to set  the hostname as NiFi uses the hostname unique to each NiFi node here.  All you configure is the port (must be an unused, non-privileged (>1024) ) and Base path (default set to "contentListener").

So any requests received by the listener on a specific node will be processed by that specific node unless you programmatically via your flow redistributed those requests to other nodes via load balanced configured connection.

What is commonly done here is to have an external load-balancer in front of your NiFi cluster that handles distributing requests across all your listeners running on the different cluster nodes. 

NOTE: when using an external load-balancer in front of NiFi's UI URL, you must configured session affinity (sticky sessions) in that load balancer.  This is not necessary if you are only using the external LB for endpoints like listener since those end points do not use token based authentication)

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Thank you,
Matt

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