Yes, Presently there is no config option for enabling or disabling r/o and turned on by default. I also feel it can be turned off by default and can give config options (IMO we can follow the similar pattern of 'Observer' ZooKeeper server startup.)
For ex: In zoo.cfg,
If you agree I can work on the approach. Suggest me if any better solution.
Cause of exception:-
After spawing the rozk, quorumpeer is going ahead with lookForLeader().
Since this has completed within 'sleep(Math.max(2000, tickTime));' and interrupting rozk thread inorder to avoid the startup of rozk('fastfail' approach).