Major Description
In master branch master acts also as regionserver hosting 'hbase:meta' table and it has ephemeral znode created in '/hbase/rs'. Because of this rolling-restart.sh --graceful will pick up master server from zk at this line:
online_regionservers=`$bin/hbase zkcli ls $zkrs 2>&1 | tail -1 | sed "s/\[//" | sed "s/\]//"`
and will restart it a long with rest of regionservers.
I'm planing to add some code to rolling-restart.sh script to filter master server from above list.