code: private void validateClusterForRebalance(RebalancePlan rebalancePlan) {
          logger.info("Validating state of deployed cluster to confirm its ready for rebalance.");
          Cluster finalCluster = rebalancePlan.getFinalCluster();
          List<StoreDefinition> finalStoreDefs = rebalancePlan.getFinalStores();
  
          // Reset the cluster that the admin client points at
          adminClient.setAdminClientCluster(finalCluster);
          // Validate that all the nodes ( new + old ) are in normal state
          adminClient.rebalanceOps.checkEachServerInNormalState(finalCluster);
          // Verify all old RO stores exist at version 2
          adminClient.rebalanceOps.validateReadOnlyStores(finalCluster,
                                                          finalStoreDefs);
      }
docs: Validates deployed cluster:
  <ul>
  <li>sets local admin client to finalCluster
  <li>checks that all servers are currently in normal state
  <li>confirms read-only stores can be rebalanced.
  </ul>
  
  @param rebalancePlan