code: public void failover(int index, boolean rebalance) {
          configurationRwLock.writeLock().lock();
          try {
              Info.incrementConfigRevision();
              if (index >= 0 && index < servers.length) {
                  servers[index].shutdown();
              }
              if (rebalance) {
                  rebalance();
              }
          } finally {
              Info.incrementConfigRevision();
              configurationRwLock.writeLock().unlock();
          }
      }
docs: Fail over one of the bucket's nodes
  @param index The index of the node to fail over. This index
  is the index of the node within the {@link #servers}
  (or {@link #getServers()} array; not the logical index
  within the vBucket map!
  @param rebalance Should we rebalance after failover
  
  Note this will also automatically rebalance the cluster