In the event that the analytics.sh script fails to run with "java.io.IOException: Can't get master address from ZooKeeper; znode data == null", it is likely that the HBase instance being utilized is either not running, or the HMaster instance specifically is not running.
To confirm this, access the HBase web interface (e.g. http://<ANALYTICS>:60010) and check whether the environment is fully available. In the event that the web interface does not load, it is possible that the HMaster instance is down. Start whatever HBase instances are required to bring the environment back to an operational status.