The open and close index APIs allow to close an index, and later on opening it. A closed index has almost no overhead on the cluster (except for maintaining its metadata), and is blocked for read/write operations. A closed index can be opened which will then go through the normal recovery process.
打开／关闭索引API允许关闭一个索引，可以在后来再打开它。一个已经关闭的索引几乎不会在集群中更新（除非修改了索引的元数据信息），并且不能被读写。一个已经关闭的索引可以被打开然后进入正常的索引恢复流程。
REST的端点格式为 /{index}/_close 和 /{index}/_open 。举例如下：
curl -XPOST 'localhost:9200/my_index/_close' curl -XPOST 'localhost:9200/my_index/_open'
