Newbie Questions about Cluster Node Identification

[ni...@gmail.com]

Hello all and apologies for the long first couple of questions.

I'm working on some infrastructure automation spinning up unsecured NiFi
Clusters on EC2. I see from the Administrators Guide
<https://nifi.apache.org/docs/nifi-docs/html/administration-guide.html#cluster-node-identities>.
that there should be a property set in authorizers.xml for each node in a
cluster for the Cluster Node Identity what value should be set here? The
example seems to be a person record in an LDAP Directory. I'm picking up
some work that a colleague did some years ago and they have not set any
such value in our existing clusters :(

 The background to this question is that we would like to periodically
replace the node with one based on a newer AMI (my automation installs and
configures NiFi) and have the new host rejoin the cluster at the same node
address so that cluster membership appears constant. At the moment this
succeeds but leaves *two* hosts - the old one in a disconnected state and
the new one connected. My hypothesis is that this occurs because we are not
setting node identities.

O/S is RedHat Linux
The NiFi version (currently) is 1.8!!!
ZooKeeper is external

thanks in advance and apologies for the no doubt many misconceptions I have
shown above
-- 
Niall Litchfield