There is an example here, near the bottom of the page; https://docs.hortonworks.com/HDPDocuments/Cloudbreak/Cloudbreak-2.4.2/content/security-kerberos/index.html If that doesn't help you, can you share what you've used that is giving you an error? ... View more

Did you pre-load the ambari database schema as described here at step 4; https://docs.hortonworks.com/HDPDocuments/Ambari-2.6.2.2/bk_ambari-administration/content/using_ambari_with_postgresql.html ... View more

Hi @Seongmin Park The "NiFi Flow" itself is also a process group, see on the left hand side when you log in, note the Process group ID that belongs to my NiFi Flow. I will also set a var on the NiFi Flow and retrieve it with REST: Setting a random var on it; And getting the variable data of the NiFi Flow over REST: [root@c3175-node4 ~]# curl -i -X GET http://172.25.35.14:9090/nifi-api/process-groups/dadadbcd-0164-1000-16c1-6c50ce94361e/variable-registry HTTP/1.1 200 OK Date: Thu, 02 Aug 2018 09:34:52 GMT Content-Type: application/json Content-Length: 362 {"processGroupRevision":{"clientId":"f9e30047-0164-1000-e3ba-51b6ec77ae6f","version":3},"variableRegistry":{"variables":[{"variable":{"name":"FlowVarExample","value":"This is a flow variable example : - )","processGroupId":"dadadbcd-0164-1000-16c1-6c50ce94361e","affectedComponents":[]},"canWrite":true}],"processGroupId":"dadadbcd-0164-1000-16c1-6c50ce94361e"}} ... View more

Hi @Seongmin Park Yes, this is possible with the REST API. For example, I made a process group with 1 variable "TestVariable" and content "Hello Seongmin" Now to get this using REST, I run; curl -i -X GET http://172.25.36.20:9090/nifi-api/process-groups/<your group id here>/variable-registry And the output from that rest query HTTP/1.1 200 OK Date: Wed, 01 Aug 2018 08:33:32 GMT Content-Type: application/json Content-Length: 337 {"processGroupRevision":{"clientId":"f49c73f5-0164-1000-48ef-ef1af0585eca","version":4},"variableRegistry":{"variables":[{"variable":{"name":"TestVariable","value":"Hello Seongmin","processGroupId":"f49c4d0a-0164-1000-ffff-ffffb54b15e2","affectedComponents":[]},"canWrite":true}],"processGroupId":"f49c4d0a-0164-1000-ffff-ffffb54b15e2"}} ... View more