code: public boolean isHealthy() {
          return health()
                  .map(health -> !"red".equals(health.path("status").asText()) && indexSetRegistry.isUp())
                  .orElse(false);
      }
docs: Check if the cluster health status is not {@literal RED} and that the
  {@link IndexSetRegistry#isUp() deflector is up}.
  
  @return {@code true} if the the cluster is healthy and the deflector is up, {@code false} otherwise