By default, Elasticsearch will use the first seven characters of the randomly generated UUID as the node id. Note that the node id is persisted and does not change when a node restarts and therefore the default node name will also not change.

It is worth configuring a more meaningful name which will also have the advantage of persisting after restarting the node: prod-data-2

The can also be set to the server’s HOSTNAME as follows: ${HOSTNAME}