Imply includes a tested, stable version of open source Druid. We are committed to developing open source Druid. If you have an existing Druid cluster, it's easy to migrate to and from Imply.
If you are happy with how your Druid services are currently configured, you can deploy the Imply distribution in the same configuration with minimal changes.
If you additionally want to combine your existing Druid Coordinators and Druid Overlords into Master servers:
bin/supervise -c conf/supervise/master-without-zk.conf. These new Master servers will connect to your existing ZooKeeper and metadata store. We recommend running with two Master servers to support failover.