private boolean movePrimaries() {
    Move bestMove = model.findBestPrimaryMove();

    if (bestMove == null) {
      return false;
    }

    model.movePrimary(bestMove);

    return true;
  }
Move a single primary from one member to another

@return if we are able to move a primary.
geode-core/src/main/java/org/apache/geode/internal/cache/partitioned/rebalance/MovePrimaries.java