Adding a ZooKeeper Role

Describes how to add a ZooKeeper role to a data-fabric node using the CLI.

If you are increasing the number of ZooKeeper roles in the cluster, for example from one to three, shut down the cluster before you add the role to the nodes to prevent any problems and then start the cluster upon completion.

Complete the following steps to add the ZooKeeper role to a node:

Install the ZooKeeper package corresponding to the new role.
Run configure.sh -Z on the node where you added the new ZooKeeper role.
Using the -Z option provides the list of ZooKeeper nodes that includes the new node.
Run configure.sh -Z on all other nodes in the cluster.
Using the -Z option to provide the list of ZooKeeper nodes that includes the new node.
Issue the following command to start or restart ZooKeeper on the node where you added the ZooKeeper role:
```
% service mapr-zookeeper restart
```
Perform a rolling restart of ZooKeeper on all other ZooKeeper nodes.
A rolling restart of ZooKeeper means restart ZooKeeper on each node, one at a time, pausing until the last restart finishes before beginning the next. Restart the ZooKeeper leader last.
Issue the following command to verify that the new node joined the ZooKeeper quorum:
```
% service mapr-zookeeper qstatus
```
Perform a rolling restart of Warden on all other nodes.
Warden picks up the new ZooKeeper node. Issue the following command to restart Warden on the node where you installed the role:
```
% service mapr-warden restart
```