Replacing a running node

Steps to replace a node with a new node, such as when updating to newer hardware or performing proactive maintenance.

You must prepare and start the replacement node, integrate it into the cluster, and then decommission the old node.

Note: To change the IP address of a node, simply change the IP of node and then restart Cassandra. If you change the IP address of a seed node, you must update the -seeds parameter in the seed_provider for each node in the file.

The location of the cassandra.yaml file depends on the type of installation:

Package installations	/etc/cassandra/cassandra.yaml
Tarball installations	`install_location`/resources/cassandra/conf/cassandra.yaml

Procedure

Be sure to install the same version of Cassandra as is installed on the other nodes in the cluster.

Prepare and start the replacement node, as described in Adding nodes to an existing cluster.

Note: If not using vnodes, see Adding or replacing single-token nodes.
Confirm that the replacement node is alive:
- Run nodetool ring if not using vnodes.
- Run nodetool status if using vnodes.
The status should show:
- nodetool ring: Up
- nodetool status: UN
Note the Host ID of the node; it is used in the next step.
Using the Host ID of the original node, decommission the original node from the cluster using the nodetool decommission command.