This command can be used to create or manage the ZooKeeper ensemble for Fuse Fabric.
There are four different usages:

* fabric:ensemble-list
The list of containers composing the current ensemble will be displayed.

* fabric:ensemble-create [list of containers]
This mode will create a new ensemble composed of the given containers and will switch all containers to this new ensemble.

* fabric:ensemble-add [list of containers]
This mode will add the given containers to the ensemble. All containers will be switched to this new ensemble.

* fabric:ensemble-remove [list of containers]
This mode will create a new ensemble composed of the existing containers excluding the containers specified on the command line. All containers will be switched to this new ensemble.

Note that given ZooKeeper is the key component of Fabric, changing the ZooKeeper ensemble is a critical operation.  All data will be preserved and copied to the new ensemble before switching.
