Kubernetes metrics-server： kubectl top nodes Error from server (ServiceUnavailable): 怎么解决？

部署metrics-server时，pod能正常启动，但是不能正常使用

 kubectl top pods
Error from server (ServiceUnavailable): the server is currently unable to handle the request (get pods.metrics.k8s.io)

查看日志如下：

# kubectl logs -f pod/metrics-server-7cccb5464-n8wwn  -n kube-system -c metrics-server                      
I0404 05:21:09.136867       1 serving.go:273] Generated self-signed cert (apiserver.local.config/certificates/apiserver.crt, apiserver.local.config/certificates/apiserver.key)
[restful] 2019/04/04 05:21:10 log.go:33: [restful/swagger] listing is available at https://:443/swaggerapi
[restful] 2019/04/04 05:21:10 log.go:33: [restful/swagger] https://:443/swaggerui/ is mapped to folder /swagger-ui/
I0404 05:21:10.729295       1 serve.go:96] Serving securely on [::]:443
----------------------------------------------------

kube-api中已经加了聚合层配置

  --requestheader-client-ca-file=/etc/kubernetes/ssl/ca.pem \
  --requestheader-allowed-names=aggregator \
  --requestheader-extra-headers-prefix=X-Remote-Extra- \
  --requestheader-group-headers=X-Remote-Group \
  --requestheader-username-headers=X-Remote-User \

试了好多种办法，也没有解决。