putting cassandra nodes into readonly mode before we kill it, to avoid data loss
politely stopping zookeeper before we kill -9 it, to avoid data loss
added missing docstring
Merge remote-tracking branch 'org/testing' into safely-preserve-persisted-data
Merge remote-tracking branch 'org/testing' into safely-preserve-persisted-data
removed references to hypertable
Merge pull request #666 from shatterednirvana/safely-preserve-persisted-data

Safely preserve persisted data