code: public synchronized String lookupContainer(String lookup) {
          if (aliasToContainerMap.containsKey(lookup)) {
              return aliasToContainerMap.get(lookup);
          }
          return imageToContainerMap.get(lookup);
      }
docs: Lookup a container by name or alias from the tracked containers
  
  @param lookup name or alias of the container to lookup
  @return container id found or <code>null</code>