来自https://github.com/etcd-io/etcd/blob/master/Documentation/op-guide/configuration.md
--listen-client-urls
List of URLs to listen on for client traffic. This flag tells the etcd to accept incoming requests from the clients on the specified scheme://IP:port combinations.
--advertise-client-urls
List of this member's client URLs to advertise to the rest of the cluster. These URLs can contain domain names.
我从字面上理解它们的含义。
但是，如果我不想打开address：port到客户端，为什么要让etcd监听呢？