app.conf配置外置etcd三节点集群地址，当外置etcd一个节点故障时，无法连接etcd

[jacthy]

Describe the bug app.conf配置外置etcd三节点集群地址，当外置etcd一个节点故障时，无法连接etcd

To Reproduce Steps to reproduce the behavior:

1. app.conf配置外置etcd三节点集群地址
2. 启动外置etcd后，让etcd出现单节点故障，但集群是可服务的
3. 启动servicecomb-service-center服务
4. 发现servicecomb无法连接etcd

Expected behavior etcd集群正常，servicecomb应该要可以连上集群正常工作

Platform And Runtime (please complete the following information):

Platform

• OS: linux
• Browser [e.g. chrome, safari]
• Version 0.0

Runtime

• Version [e.g. Go 1.11]

Additional context Add any other context about the problem here.

[tianxiaoliang]

请问下使用的sc版本是什么，请将配置文件脱敏后发出来

[little-cui]

建议你使用分支v1.x 运行代码，看是否问题依然存在