protected boolean hasAllocatedResource(String host) {
    return peekAllocatedResource(host) != null;
  }
Returns true if there are resources allocated on a host.
@param host  the host for which a resource is needed.
@return      {@code true} if there is a resource allocated for the specified host, {@code false} otherwise.
samza-core/src/main/java/org/apache/samza/clustermanager/ContainerAllocator.java