⽔平扩展的痛点

单集群 – 当⽔平扩展时，节点数不能⽆限增加
- 当集群的 meta 信息（节点，索引，集群状态）过多，会导致更新压⼒变⼤，单个 Active Master 会成为性能瓶颈，导致整个集群⽆法正常⼯作
早期版本，通过 Tribe Node 可以实现多集群访问的需求，但是还存在⼀定的问题
- Tribe Node 会以 Client Node 的⽅式加⼊每个集群。集群中 Master 节点的任务变更需要 Tribe Node 的回应才能继续
- Tribe Node 不保存 Cluster State 信息，⼀旦重启，初始化很慢
- 当多个集群存在索引重名的情况时，只能设置⼀种 Prefer 规则

跨集群搜索 - Cross Cluster Search

早期 Tribe Node 的⽅案存在⼀定的问题，现已被 Deprecated
Elasticsearch 5.3 引⼊了跨集群搜索的功能(Cross Cluster Search)，推荐使⽤
- 允许任何节点扮演 federated 节点，以轻量的⽅式，将搜索请求进⾏代理
- 不需要以 Client Node 的形式加⼊其他集群

配置及查询

PUT _cluster/settings
{
  "persistent": {
    "cluster": {
      "remote": {
        "cluster0": {
          "seeds": [
            "127.0.0.1:9300"
          ],
          "transport.ping_schedule": "30s"
        },
        "cluster1": {
          "seeds": [
            "127.0.0.1:9301"
          ],
          "transport.compress": true,
          "skip_unavailable": true
        },
        "cluster2": {
          "seeds": [
            "127.0.0.1:9302"
          ]
        }
      }
    }
  }
}

GET /cluster_one:tmdb,movies/_search
{
  "query": {
    "match": {
      "title": "matrix"
    }
  }
}

PUT _cluster/settings
{
  "persistent": {
    "cluster.remote.cluster_two.skip_unavailable": true
  }
}

Demo

配置跨集群搜索
每个集群创建相同的索引名，并写⼊数据
跨集群搜索
在 Kibana 的 Index Pattern 中配置跨集群搜索 *:users

Index Pattern

本节知识点回顾

当集群⽆法⽔平扩展，或者需要将不同的集群数据实现数据的 Federation，可以采⽤跨集群搜索（CCS）
Tribe Node 和 Cross Cluster Search 的⽐较，推荐在新版本中使⽤ CCS
如何配置并使⽤ Cross Cluster Search 查询数据

课程demo

//启动3个集群

bin/elasticsearch -E node.name=cluster0node -E cluster.name=cluster0 -E path.data=cluster0_data -E discovery.type=single-node -E http.port=9200 -E transport.port=9300
bin/elasticsearch -E node.name=cluster1node -E cluster.name=cluster1 -E path.data=cluster1_data -E discovery.type=single-node -E http.port=9201 -E transport.port=9301
bin/elasticsearch -E node.name=cluster2node -E cluster.name=cluster2 -E path.data=cluster2_data -E discovery.type=single-node -E http.port=9202 -E transport.port=9302


//在每个集群上设置动态的设置
PUT _cluster/settings
{
  "persistent": {
    "cluster": {
      "remote": {
        "cluster0": {
          "seeds": [
            "127.0.0.1:9300"
          ],
          "transport.ping_schedule": "30s"
        },
        "cluster1": {
          "seeds": [
            "127.0.0.1:9301"
          ],
          "transport.compress": true,
          "skip_unavailable": true
        },
        "cluster2": {
          "seeds": [
            "127.0.0.1:9302"
          ]
        }
      }
    }
  }
}

#cURL
curl -XPUT "http://localhost:9200/_cluster/settings" -H 'Content-Type: application/json' -d'
{"persistent":{"cluster":{"remote":{"cluster0":{"seeds":["127.0.0.1:9300"],"transport.ping_schedule":"30s"},"cluster1":{"seeds":["127.0.0.1:9301"],"transport.compress":true,"skip_unavailable":true},"cluster2":{"seeds":["127.0.0.1:9302"]}}}}}'

curl -XPUT "http://localhost:9201/_cluster/settings" -H 'Content-Type: application/json' -d'
{"persistent":{"cluster":{"remote":{"cluster0":{"seeds":["127.0.0.1:9300"],"transport.ping_schedule":"30s"},"cluster1":{"seeds":["127.0.0.1:9301"],"transport.compress":true,"skip_unavailable":true},"cluster2":{"seeds":["127.0.0.1:9302"]}}}}}'

curl -XPUT "http://localhost:9202/_cluster/settings" -H 'Content-Type: application/json' -d'
{"persistent":{"cluster":{"remote":{"cluster0":{"seeds":["127.0.0.1:9300"],"transport.ping_schedule":"30s"},"cluster1":{"seeds":["127.0.0.1:9301"],"transport.compress":true,"skip_unavailable":true},"cluster2":{"seeds":["127.0.0.1:9302"]}}}}}'


#创建测试数据
curl -XPOST "http://localhost:9200/users/_doc" -H 'Content-Type: application/json' -d'
{"name":"user1","age":10}'

curl -XPOST "http://localhost:9201/users/_doc" -H 'Content-Type: application/json' -d'
{"name":"user2","age":20}'

curl -XPOST "http://localhost:9202/users/_doc" -H 'Content-Type: application/json' -d'
{"name":"user3","age":30}'


#查询
curl -XPOST "http://localhost:9200/users,cluster1:users,cluster2:users/_search" -H 'Content-Type: application/json' -d'{"query":{"range":{"age":{"gte":20,"lte":40}}}}'

POST /users,cluster1:users,cluster2:users/_search
{
  "query": {
    "range": {
      "age": {
        "gte": 20,
        "lte": 40
      }
    }
  }
}