code: private Observable<ProposedBucketConfigContext> refreshAgainstNode(final String bucketName,
          final NetworkAddress hostname) {
          final Credential credential = registrations().get(bucketName);
          if (credential == null) {
              LOGGER.debug("Ignoring refresh attempt since it seems the bucket registration is gone (closed).");
              return Observable.empty();
          }
  
          return Observable.defer(new Func0<Observable<BucketConfigResponse>>() {
              @Override
              public Observable<BucketConfigResponse> call() {
                  return cluster()
                      .<BucketConfigResponse>send(new BucketConfigRequest(HttpLoader.TERSE_PATH, hostname, bucketName,
                          credential.username(), credential.password()))
                      .flatMap(new Func1<BucketConfigResponse, Observable<BucketConfigResponse>>() {
                          @Override
                          public Observable<BucketConfigResponse> call(BucketConfigResponse response) {
                              if (response.status().isSuccess()) {
                                  LOGGER.debug("Successfully got config refresh from terse bucket remote.");
                                  return Observable.just(response);
                              }
  
                              LOGGER.debug("Terse bucket config refresh failed, falling back to verbose.");
                              return cluster().send(
                                  new BucketConfigRequest(HttpLoader.VERBOSE_PATH, hostname, bucketName,
                                      credential.username(), credential.password()));
                          }
                      });
              }
          }).map(new Func1<BucketConfigResponse, ProposedBucketConfigContext>() {
              @Override
              public ProposedBucketConfigContext call(final BucketConfigResponse response) {
                  String config = response.config().replace("$HOST", hostname.address());
                  return new ProposedBucketConfigContext(bucketName, config, hostname);
              }
          }).doOnError(new Action1<Throwable>() {
              @Override
              public void call(Throwable ex) {
                  LOGGER.debug("Could not fetch config from bucket \"" + bucketName + "\" against \""
                      + hostname + "\".", ex);
              }
          });
      }
docs: Helper method to fetch a config from a specific node of the cluster.
  
  @param bucketName the name of the bucket.
  @param hostname the hostname of the node to fetch from.
  @return a raw configuration or an error.