This feature required a bit of refactoring to the plugin interface itself as
well as a restriction on the configuration so that either only one plugin could
be specified or an ulimited number of security-setting matches. This was done
to prevent messy situations where a plugin could update settings from the XML
or even another plugin if there were overlapping matches.
Its now possible to also add the broker name to jmx tree avoiding clashes when multiple brokers are in a single vm. This is now the default but the old way can be used with some configuration
https://issues.apache.org/jira/browse/ARTEMIS-311
The failback process needs to be deterministic rather than relying on various
incarnations of Thread.sleep() at crucial points. Important aspects of this
change include:
1) Make the initial replication synchronization process block at the very
last step and wait for a response from the replica to ensure the replica has
as the necessary data. This is a critical piece of knowledge during the
failback process because it allows the soon-to-become-backup server to know
for sure when it can shut itself down and allow the soon-to-become-live
server to take over. Also, introduce a new configuration element called
"initial-replication-sync-timeout" to conrol how long this blocking will occur.
2) Set the state of the server as 'LIVE' only after the server is fully
started. This is necessary because once the soon-to-be-backup server shuts
down it needs to know that the soon-to-be-live server has started fully before
it restarts itself as the new backup. If the soon-to-be-backup server restarts
before the soon-to-be-live is fully started then it won't actually become a
backup server but instead will become a live server which will break the
failback process.
3) Wait to receive the announcement of a backup server before failing-back.
