fix: prefer EMQX 6.x to load DS cluster view

This commit ensures that DS reconcilers prefer to work with the same
cluster view, preferably sourced from 6.x, primarily because EMQX
clusters running 6.1.0 and newer can have separate cluster views
different from 6.0.x and earlier.

Author: keynslug

internal/controller/ds_load_cluster_state.go

@@ -14,7 +14,12 @@ type dsLoadClusterState struct {
 
 func (c *dsLoadClusterState) reconcile(r *reconcileRound, instance *crd.EMQX) subResult {
 	// Instantiate API requester for a node that is part of the core StatefulSet.
-	req := r.oldestCoreRequester()
+	// Prefer EMQX 6.x requester first: EMQX starting from 6.1.0 has separate cluster view.
+	req := r.requester.forOldestCore(r.state, &emqxVersionFilter{instance: instance, prefix: "6."})
+	if req == nil {
+		req = r.oldestCoreRequester()
+	}
+
 	// If there's no suitable EMQX API to query, skip the reconciliation.
 	if req == nil {
 		return reconcilePostpone()

internal/controller/ds_update_replica_sets.go

@@ -28,7 +28,11 @@ func (u *dsUpdateReplicaSets) reconcile(r *reconcileRound, instance *crd.EMQX) s
 	}
 
 	// Instantiate API requester for a node that is part of the core StatefulSet.
-	req := r.requester.forOldestCore(r.state)
+	// Prefer EMQX 6.x requester first: EMQX starting from 6.1.0 has separate cluster view.
+	req := r.requester.forOldestCore(r.state, &emqxVersionFilter{instance: instance, prefix: "6."})
+	if req == nil {
+		req = r.oldestCoreRequester()
+	}
 
 	// If there's no EMQX API to query, skip the reconciliation.
 	if req == nil {