(Tested with NiFi 2.0.0-M1 and MiNiFi c++ 0.15.0.)

  1. Install NiFi.  When you a access https://<hostname>:8443/nifi/ the first time in your browser, you will get a "Potential Security Risk Ahead" warning about NiFi's self-signed certificate, but you can click Advanced → Accept the Risk and Continue.


  2. Create a NiFi flow with an Input Port.  Double-click the Input Port, and note its ID (1342ea64-018d-1000-a5cf-7bda6830909b in the screenshot.)


     


  3. Create a MiNiFi flow with a Remote Processing Group and an Input Port as shown in this example: https://github.com/apache/nifi-minifi-cpp/blob/main/examples/site_to_site_config.yml.  Update


  4. Create a self-signed certificate; there are many how-tos on the internet.  Below, we'll assume that your generated files are /opt/certs/agent-cert.pem and /opt/certs/agent-key.pem; the CN of the certificate is "my-agent-ID".


  5. Add the following settings to your NiFi installation's nifi.properties file:

    # Site to Site properties
nifi.remote.input.host=localhost
nifi.remote.input.secure=true
nifi.remote.input.socket.port=7777
nifi.remote.input.http.enabled=true

    Note that the port you configure here, 7777 in this example, will be used internally by the site-to-site communication, but in the MiNiFi config.yml file, you should use the same NiFi address you use in your browser, NOT this site-to-site port.


  6. Export the NiFi certificate from the NiFi trust store, and import the MiNiFi agent certificate into the NiFi trust store: 

    keytool -exportcert -alias nifi-cert -rfc -keystore truststore.p12 > /opt/certs/nifi-cert.pem
keytool -importcert -alias agent-cert -file /opt/certs/agent-cert.pem -keystore truststore.p12

    keytool will prompt you for the truststore password; you can get this from the nifi.properties file.


  7. Add the agent ID (which is the CN of the agent certificate) as the "Initial User Identity 1" value in the "userGroupProvider" section of authorizers.xml in your NiFi installation:

        <userGroupProvider>
        <identifier>file-user-group-provider</identifier>
        <class>org.apache.nifi.authorization.FileUserGroupProvider</class>
        <property name="Users File">./conf/users.xml</property>
        <property name="Initial User Identity 1">my-agent-ID</property>
    </userGroupProvider>

    and restart NiFi; it will create a new user in users.xml which looks like this:

    <tenants>
    <groups/>
    <users>
        <user identifier="9a889e09-6e86-360a-a324-8f3ee341842a" identity="my-agent-ID"/>
    </users>
</tenants>


  8. Add authorizations for your user in authorizations.xml in your NiFi installation, copying the user identifier from users.xml:

    <authorizations>
    <policies>
        <policy identifier="1f6ae57a-08bc-11eb-9242-bf69163fde10" resource="/site-to-site" action="R">
          <!-- copy the user identifier from users.xml -->
          <user identifier="9a889e09-6e86-360a-a324-8f3ee341842a"/>
        </policy>
        <policy identifier="282818e0-08bc-11eb-8508-2b51c9d70d42" resource="/site-to-site" action="W">
          <user identifier="9a889e09-6e86-360a-a324-8f3ee341842a"/>
        </policy>
         
        <!-- copy the port identifier from the Input Port in NiFi into the resource string -->
        <policy identifier="f512f796-7afb-4c9f-ab68-b5eaf6d5d0cf" resource="/data-transfer/input-ports/c171f9da-689f-41e2-98c4-9d785c59c306" action="R">
          <user identifier="9a889e09-6e86-360a-a324-8f3ee341842a"/>
        </policy>
        <policy identifier="b4e836ee-d526-4e16-8bf3-ee1d8fa3d5e6" resource="/data-transfer/input-ports/c171f9da-689f-41e2-98c4-9d785c59c306" action="W">
          <user identifier="9a889e09-6e86-360a-a324-8f3ee341842a"/>
        </policy>
  
        <!-- you will also need a pair of policies for resource="/data-transfer/output-ports/..." if you want S2S data transfer from NiFi to MiNiFi -->
   </policies>
</authorizations>


  9. Restart NiFi again, and test that you can connect to it using https:

    # This should give a large HTML response
curl -k --key /opt/certs/agent-key.pem --cert /opt/certs/agent-cert.pem https://<hostname>:8443/nifi/

# This should give a JSON response
curl -k --key /opt/certs/agent-key.pem --cert /opt/certs/agent-cert.pem https://<hostname>:8443/nifi-api/site-to-site/


  10. Finally, configure MiNiFi to use secure site-to-site:

    nifi.remote.input.secure=true
nifi.security.need.ClientAuth=true
nifi.security.client.certificate=/opt/certs/agent-cert.pem
nifi.security.client.private.key=/opt/certs/agent-key.pem
nifi.security.client.pass.phrase=<key passphrase if any>
nifi.security.client.ca.certificate=/opt/certs/nifi-cert.pem

# These are not needed
#nifi.rest.api.user.name=
#nifi.rest.api.password=


  11. Restart MiNiFi.  It should be sending data to NiFi now.  Congratulations!