When a data node starts up, the broker URLs were not set before
they were actually being used. The call to client.Open() in
turn triggers the raft streamer and heartbeat which try to connect
to the broker. If those started before the subsequent client.SetURLs()
call, you would see the following error in the logs at startup:
[messaging] 2015/04/01 11:59:22 reconnecting to broker: url={ <nil> /messaging/messages index=2&streaming=true&topicID=0 }, err=Get /messaging/messages?index=2&streaming=true&topicID=0: unsupported protocol scheme ""
Fixing this race uncovered another bug where the join urls would be
cleared the first time the broker was started. In this case, the
join urls should be left alone since they were set properly w/ SetURLs.
Fixes#2152
This sends data node urls via the broker heartbeat from each data
node. The urls are tracked on the broker to support simpler
cluster setup as well as distributed queries.
* Update the infludb broker to not need a server so that it'll work on non-data node servers
* Update messaging broker to keep track of connect urls for replicas