Trying to implement above on existing cluster unsuccessfully. Took down all mongod and see following:

-bash-4.1$ chmod 700 ./mongodb-linux-x86_64-2.0.2/sec/key1
-bash-4.1$ ./mongodb-linux-x86_64-2.0.2/bin/mongod --dbpath /app/data/db/ --fork --logpath /app/mongolog/mongodb.log --shardsvr --keyFile ./mongodb-linux-x86_64-2.0.2/sec/key1
-bash-4.1$ forked process: 11235
all output going to: /app/mongolog/mongodb.log

-bash-4.1$ tail -f /app/mongolog/mongodb.log
Tue Jan 31 08:20:30 dbexit:
Tue Jan 31 08:20:30 shutdown: going to close listening sockets...
Tue Jan 31 08:20:30 shutdown: going to flush diaglog...
Tue Jan 31 08:20:30 shutdown: going to close sockets...
Tue Jan 31 08:20:30 shutdown: waiting for fs preallocator...
Tue Jan 31 08:20:30 shutdown: lock for final commit...
Tue Jan 31 08:20:30 shutdown: final commit...
Tue Jan 31 08:20:30 shutdown: closing all files...
Tue Jan 31 08:20:30 closeAllFiles() finished
Tue Jan 31 08:20:30 dbexit: really exiting now