Basically, adding nodes (hosts) requires no downtime and will not affect running jobs at all. Btw, you may try to do this by Ambari Add Hosts function. Scenario: 1. Go to Ambari Hosts page. 2. Click on Actions button located on the top left of this page. 3. Select "Add New Hosts " option. You will see a wizard which will guide you through the whole process, you can add hosts with any slaves (DataNode, NodeManager, clients .etc) installed on them. Hope this helps 🙂 ... View more