Primary rebalancing automatically occurs in cases where changes in the cluster status could potentially affect the distribution of primary buckets. A rolling restart completion causes nodes to restart sequentially and re-assume their roles, requiring rebalancing for optimal performance. When a master node rejoins the cluster, it can change the cluster configuration and thus trigger rebalancing to distribute primary buckets efficiently. Similarly, a peer node joining or rejoining the cluster affects the distribution of data across the nodes and prompts rebalancing to ensure even distribution of primary buckets.