Clarify when changing number of cores is supported (#850)

Co-authored-by: Jake Cahill <[email protected]>

Author: kbatuigas

modules/manage/pages/cluster-maintenance/cluster-balancing.adoc

@@ -125,13 +125,15 @@ This is a beta feature for v24.2 and is not recommended for use for production c
 ```bash
 curl -X PUT -d '{"state": "active"}' http://127.0.0.1:9644/v1/features/node_local_core_assignment
 ```
+
+xref:24.3@ROOT:upgrade:index.adoc[Upgrade to 24.3 or later] to use this feature for production clusters.
 ====
 
 In Redpanda, every partition replica is assigned to a CPU core on a broker. While Redpanda's default <<partition-replica-balancing,partition balancing>> monitors cluster-level events, such as the addition of new brokers or broker failure to balance partition assignments, it does not account for the distribution of partitions _within_ an individual broker. 
 
-Prior to Redpanda version 24.2, this meant that some cores on a broker could inadvertently host many partitions of heavily-used topics and cause the CPU to be xref:manage:monitoring.adoc#cpu-usage[overburdened]. Additionally, when the partition rebalance moved some partitions away from a broker, the remaining partitions did not necessarily rebalance across the broker's cores. Or, if a broker's core count was increased, Redpanda did not assign any partitions to the new cores until new partitions were created or old partitions were moved out.
+Starting in this version of Redpanda, topic-aware intra-broker partition balancing allows for dynamically reassigning partitions within a broker.  Redpanda prioritizes an even distribution of a topic's partition replicas across all cores in a broker. If a broker's core count changes, when the broker starts back up, Redpanda can check partition assignments across the broker's cores and reassign partitions, so that a balanced assignment is maintained across all cores. Redpanda can also check partition assignments when partitions are added to or removed from a broker, and rebalance the remaining partitions between cores.
 
-Starting in v24.2, topic-aware intra-broker partition balancing allows for dynamically reassigning partitions within a broker.  Redpanda prioritizes an even distribution of a topic's partition replicas across all cores in a broker. If a broker's core count changes, when the broker starts back up, Redpanda can check partition assignments across the broker's cores and reassign partitions, so that a balanced assignment is maintained across all cores. Redpanda can also check partition assignments when partitions are added to or removed from a broker, and rebalance the remaining partitions between cores.
+NOTE: Decreasing the number of CPU cores in a running cluster requires that you enable the `node_local_core_assignment` feature flag.
 
 To determine when to use intra-broker partition balancing, use the public metrics for CPU usage described in the xref:manage:monitoring.adoc#cpu-usage[Monitoring] guide.
 

modules/manage/pages/kubernetes/k-manage-resources.adoc

@@ -26,7 +26,9 @@ kubectl describe nodes
 
 == Limitations
 
-Redpanda does not support decreasing the CPU cores for brokers in an existing cluster.
+Decreasing the number of CPU cores in a production cluster is not supported in this version of Redpanda. However, you can enable xref:manage:cluster-maintenance/cluster-balancing.adoc#intra-broker-partition-balancing[intra-broker partition balancing] to reduce CPU cores in a development cluster.
+
+Starting from version 24.3, decreasing the number of CPU cores in a production cluster is supported. xref:24.3@ROOT:upgrade:index.adoc[Upgrade to version 24.3] or later to access this feature.
 
 [[memory]]
 == Configure memory resources