Can I move One or More Nodes from One Apache Cassandra Cluster to Another?

The short answer is it's a bad idea gone wrong; nodes should not be moved between clusters.  Data integrity issues, data loss, or other unexpected behavior are highly likely.

Technical Reasons Why Nodes Should Not be Moved Between Clusters

1. Different cluster configurations: Each Apache Cassandra cluster has its own configuration, including cluster name, seeds, replication factor, and other performance-related settings.  Moving a node between clusters with different configurations will lead to inconsistencies, data loss, or unexpected behavior.
2. Different token ranges: In an Apache Cassandra cluster, data is distributed across all nodes, where each node is responsible for a specific token range.  When a node is moved between clusters, the token ranges of the destination cluster will not align with the token ranges of the moved node, leading to data inconsistencies.
3. Different schema definitions: Cassandra clusters will probably have different schemas, including keyspaces, tables, and column types.  The schema dictates how data is structured.  Moving a node between clusters with different schemas will result in incompatibilities and data corruption.
4. Data replication and consistency: Cassandra uses a replication strategy to maintain data consistency across nodes.  When a node is moved between clusters, the new cluster's replication factor and replication strategy will probably not be compatible with the moved node, leading to data inconsistency and potential data loss.
5. Cluster membership and topology: Nodes in a Cassandra cluster maintain information about other nodes and the cluster topology using the Gossip protocol.  Moving a node between clusters can cause confusion in the cluster membership and disrupt the Gossip protocol's operation, causing data consistency and availability issues.
6. Datacenter and rack awareness: Cassandra clusters can span multiple data centers and racks to ensure high availability and fault tolerance.  Each node has information about its data center and rack.  Moving a node between clusters can lead to incorrect data center and rack assignments, affecting the performance and fault tolerance of the new cluster.