K8SSAND-1820 ⁃ Removing Stargate triggers a DC restart

[adutra]

What happened?

When Stargate is removed from a K8ssandraCluster object suing Cassandra 4.0, this triggers a DC restart.

Did you expect to see something different?

I expect no DC restart.

How to reproduce it (as minimally and precisely as possible):

1. Create a cluster with 1 DC and Stargate
2. Delete Stargate from the CRD
3. Observe the DC being restarted

Environment

• K8ssandra Operator version:

1.2

Anything else we need to know?:

Due to this code in the k8ssandra controller:

if dcConfig.ServerVersion.Major() != 3 && kc.HasStargates() {
	// if we're not running Cassandra 3.11 and have Stargate pods, we need to allow alter RF during range movements
	cassandra.AllowAlterRfDuringRangeMovement(dcConfig)
}

I suggest that we always call cassandra.AllowAlterRfDuringRangeMovement(dcConfig) for Cassandra 4.0, regardless of whether we have Stargate nodes.

See also stargate/stargate#1274.

┆Issue is synchronized with this Jira Task by Unito
┆friendlyId: K8SSAND-1820
┆priority: Medium

[adejanovski]

I suggest that we always call cassandra.AllowAlterRfDuringRangeMovement(dcConfig) for Cassandra 4.0, regardless of whether we have Stargate nodes.

I agree 👍