public List<KubernetesInstance> selectInstances(final String serviceId) {
        List<KubernetesInstance> response = Collections.emptyList();
        KubernetesInstance[] responseBody = this.rest.getForEntity(this.kubernetesConfig.getDiscoveryServerUrl() + "/apps/" + serviceId,
                KubernetesInstance[].class, new Object[0]).getBody();
        if (Objects.nonNull(responseBody) && responseBody.length > 0) {
            response = Arrays.stream(responseBody).filter(this::matchNamespaces).collect(Collectors.toList());
        }

        return response;
    }
get all serviceInstance.
@param serviceId service identifier
@return list of serviceInstance
shenyu-registry/shenyu-registry-kubernetes/src/main/java/org/apache/shenyu/registry/kubernetes/KubernetesClient.java