code: @Override
      public synchronized boolean removeHost(Host host, boolean refresh) {
          HostConnectionPool<CL> pool = hosts.remove(host);
          if (pool != null) {
              topology.removePool(pool);
              rebuildPartitions();
              monitor.onHostRemoved(host);
              pool.shutdown();
              return true;
          }
          else {
              return false;
          }
      }
docs: Remove host from the system. Shuts down pool associated with the host and rebuilds partition map
  @param host
  @param refresh