code: private static int getContainerPort(Service service, Annotation... qualifiers) {
          for (Annotation q : qualifiers) {
              if (q instanceof Port) {
                  Port port = (Port) q;
                  if (port.value() > 0) {
                      return port.value();
                  }
              }
          }
  
          ServicePort servicePort = findQualifiedServicePort(service, qualifiers);
          if (servicePort != null) {
              return servicePort.getTargetPort().getIntVal();
          }
          return 0;
      }
docs: Find the the qualfied container port of the target service
  Uses java annotations first or returns the container port.
  
  @param service
  The target service.
  @param qualifiers
  The set of qualifiers.
  
  @return Returns the resolved containerPort of '0' as a fallback.