Configuring taskmanager with HA jobmanager

[John Sherwood]

I'm attempting to move to an HA configuration with a trio of JobManagers on
top of a ZK cluster. From the docs, it appears that I should have them in
my 'masters' file (as I do), but when I attempt to start the TaskManagers,
they die complaining there is no jobmanager.rpc.address config - which
seems counter to the purpose of having the masters. Is there some other
setting I'm missing to tell the taskmanagers to use the masters file?