How to add or remove nodes in a Cassandra cluster?

6 months ago

2 minutes

Adding or removing nodes in a Cassandra cluster can be done by following these steps:

Add nodes.

Firstly, install the Cassandra software on the new node and configure the node’s IP address.
In the cassandra.yaml configuration file of the new node, the IP address, cluster name, and seed node (an existing node can be chosen as the seed node) need to be set.
Start the Cassandra service on the new node to add it to the cluster. You can use the nodetool status command to check the status of the node.

Remove node:

Firstly, stop the Cassandra service on the node that needs to be removed.
Execute the ‘nodetool decommission’ command on the other nodes in the Cassandra cluster to remove the node to be decommissioned from the cluster.
Execute the nodetool status command on other nodes to confirm that the node has been removed.

When adding or removing nodes, it is important to keep the following points in mind:

When adding a new node, make sure that the data center and replication strategy of the new node is consistent with the existing nodes to ensure data consistency and availability.
Before removing a node, make sure to migrate the data on the node first to avoid the risk of data loss or inconsistencies.
Adding or removing nodes may cause data redistribution and load balancing in a Cassandra cluster, so it is important to proceed with caution to avoid impacting the stability and performance of the cluster.