We need to update the bin scripts to support SBNs. Two ideas:
Modify start-dfs.sh to start another copy of the NN if HA is configured. We could introduce a file similar to masters (2NN hosts) called standbys which lists the SBN hosts, and start-dfs.sh would automatically make the NN it starts active (and leave the NNs listed in standby as is).
Or simpler, we could just provide a start-namenode.sh script that a user can run to start the SBN on another host themselves. The user would manually tell the other NN to be active via HAAdmin (or start-dfs.sh could do that automatically, ie assume the NN it starts should be the primary).