Adding a node and then decommissioning the old node
You must prepare and start the replacement node, integrate it into the cluster, and then decommission the old node.
Be sure to use the same version of DataStax Enterprise (DSE) on all nodes in the cluster. See Installing DataStax Enterprise 5.1.x patch releases.
Prepare and start the replacement node, as described in Adding nodes to an existing cluster.
If not using vnodes, see Adding single-token nodes to a cluster.
Confirm that the replacement node is alive:
Host IDof the original node; it is used in the next step.
Host IDof the original node, decommission the original node from the cluster using the
nodetool cleanupon all the other nodes in the same datacenter.
Failure to run
nodetool cleanupafter adding a node may result in data inconsistencies including resurrection of previously deleted data.