zh-trans: add etcd.md (#11250)

* zh-trans: add etcd.md

zh-trans: add etcd.md

* Update etcd.md

content/zh/docs/reference/glossary/etcd.md

@@ -0,0 +1,43 @@
+---
+title: etcd
+id: etcd
+date: 2018-04-12
+full_link: /docs/tasks/administer-cluster/configure-upgrade-etcd/
+short_description: >
+  etcd 是兼具一致性和高可用性的键值数据库，用作保存 Kubernetes 所有集群数据的后台数据库。
+
+aka: 
+tags:
+- architecture
+- storage
+---
+
+<!--
+---
+title: etcd
+id: etcd
+date: 2018-04-12
+full_link: /docs/tasks/administer-cluster/configure-upgrade-etcd/
+short_description: >
+  Consistent and highly-available key value store used as Kubernetes' backing store for all cluster data.
+
+aka: 
+tags:
+- architecture
+- storage
+---
+-->
+
+<!--
+ Consistent and highly-available key value store used as Kubernetes' backing store for all cluster data.
+-->
+
+etcd 是兼具一致性和高可用性的键值数据库，可以作为保存 Kubernetes 所有集群数据的后台数据库。
+
+<!--more--> 
+
+<!--
+Always have a backup plan for etcd's data for your Kubernetes cluster. For in-depth information on etcd, see [etcd documentation](https://github.com/coreos/etcd/blob/master/Documentation/docs.md).
+-->
+
+您的 Kubernetes 集群的 etcd 数据库通常需要有个备份计划。要了解 etcd 更深层次的信息，请参考 [etcd 文档](https://github.com/coreos/etcd/blob/master/Documentation/docs.md)。