public final void addComponent(Component<?, ?> component) {
        componentGroup.addComponent(component);
        if (component instanceof Handler handler) {
            ensureHandlerHasThreadpool(handler);
        }
    }
The zone this is deployed in, or the default zone if not on hosted Vespa
config-model/src/main/java/com/yahoo/vespa/model/container/ContainerCluster.java