Each node in a cluster can have slightly different configurations (I think in some respects?) but there are some parameters that must be identical on all nodes in a cluster. One of them is cluster password. This needs to be called out especially in the section previously known as:

https://access.redhat.com/documentation/en-us/red_hat_amq/7.2/html-single/using_amq_broker/#changing_the_default_cluster_user_and_password

Taking this issue further, it would be nice to have a big table of what things must be the same across nodes and what things can/must be configured per-node. (arrghhh)