code: private void undeployInstances(List<InstanceContext> instances, final CountingCompletionHandler<Void> counter) {
      for (final InstanceContext instance : instances) {
        if (instance.component().isModule()) {
          undeployModule(instance, counter);
        } else if (instance.component().isVerticle()) {
          undeployVerticle(instance, counter);
        }
      }
    }
docs: Undeploys all component instances.