ES cross cluster search跨集群查询

ES 5.3以后出的新功能。测试demo如下：

下载ES 5.5版本，然后分别本机创建2个实例，配置如下：

cluster.name: xx1
network.host: 127.0.0.1
http.port: 9200
transport.tcp.port: 9300

cluster.name: xx2
network.host: 127.0.0.1
http.port: 9201
transport.tcp.port: 9301

再创建一个实例用于跨集群搜索，配置如下：

http.port: 9202
transport.tcp.port: 9302
 
search:
    remote:
        cluster_one:
            seeds: 127.0.0.1:9300
        cluster_two:
            seeds: 127.0.0.1:9301

然后写入测试数据 es_data.json：

{ "index" : { "_index" : "test2", "_type" : "xx"}}
{ "age" : 100, "name":"bone" }

插入一条数据到9200机器：

 curl -XPOST localhost:/_bulk --data-binary @es_data.json

然后写入测试数据 es_data2.json：

{ "index" : { "_index" : "test2", "_type" : "xx"}}
{ "age" : 99, "name":"jack" }

同理再插入一条数据到9201机器：

curl -XPOST localhost:/_bulk --data-binary @es_data2.json

执行搜索：

 curl -XPOST localhost:/cluster_*:test2/xx/_search?q=*
 
{"took":,"timed_out":false,"_shards":{"total":,"successful":,"failed":},"hits":{"total":,"max_score":1.0,"hits":[{"_index":"cluster_two:test2","_type":"xx","_id":"AV-jy_6M9ed_QHEOL8Zd","_score":1.0,"_source":{ "age" : , "name":"jack" }},{"_index":"cluster_one:test2","_type":"xx","_id":"AV-jy8ivwbfD6QGw1gPg","_score":1.0,"_source":{ "age" : , "name":"bone" }}]}}

可以看到获得了两个集群的搜索数据。

执行聚合：

curl -XPOST localhost:/cluster_*:test2/xx/_search? -d '
{
  "aggs": {
    "all_age": {
      "terms": { "field": "age" }
    }
  }
}
'

返回：

{"took":,"timed_out":false,"_shards":{"total":,"successful":,"failed":},"hits":{"total":,"max_score":1.0,"hits":[{"_index":"cluster_two:test2","_type":"xx","_id":"AV-jy_6M9ed_QHEOL8Zd","_score":1.0,"_source":{ "age" : , "name":"jack" }},{"_index":"cluster_one:test2","_type":"xx","_id":"AV-jy8ivwbfD6QGw1gPg","_score":1.0,"_source":{ "age" : , "name":"bone" }}]},"aggregations":{"all_age":{"doc_count_error_upper_bound":,"sum_other_doc_count":,
 
"buckets":[{"key":99,"doc_count":1},{"key":100,"doc_count":1}]}}}

可以看到聚合的返回包含了两个集群的合并结果。

参考：

https://www.elastic.co/guide/en/elasticsearch/reference/current/modules-cross-cluster-search.html

https://www.elastic.co/guide/en/kibana/current/management-cross-cluster-search.html  kibana是可以直接支持跨集群的哈！