Elasticsearch 简明教程

Elasticsearch - Cluster APIs

群集 API 用于获取关于群集及其节点的信息并在其中进行更改。要调用此 API，我们需要指定节点名称、地址或 _local。

The cluster API is used for getting information about cluster and its nodes and to make changes in them. To call this API, we need to specify the node name, address or _local.

GET /_nodes/_local

在运行以上代码时，我们得到响应，如下所示：-

On running the above code, we get the response as shown below −

………………………………………………
cluster_name" : "elasticsearch",
   "nodes" : {
      "FKH-5blYTJmff2rJ_lQOCg" : {
         "name" : "ubuntu",
         "transport_address" : "127.0.0.1:9300",
         "host" : "127.0.0.1",
         "ip" : "127.0.0.1",
         "version" : "7.0.0",
         "build_flavor" : "default",
         "build_type" : "tar",
         "build_hash" : "b7e28a7",
         "total_indexing_buffer" : 106502553,
         "roles" : [
            "master",
            "data",
            "ingest"
         ],
         "attributes" : {
………………………………………………

Cluster Health

此 API 用于通过附加“health”关键字来获取有关群集运行状况的状态。

This API is used to get the status on the health of the cluster by appending the ‘health’ keyword.

GET /_cluster/health

在运行以上代码时，我们得到响应，如下所示：-

On running the above code, we get the response as shown below −

{
   "cluster_name" : "elasticsearch",
   "status" : "yellow",
   "timed_out" : false,
   "number_of_nodes" : 1,
   "number_of_data_nodes" : 1,
   "active_primary_shards" : 7,
   "active_shards" : 7,
   "relocating_shards" : 0,
   "initializing_shards" : 0,
   "unassigned_shards" : 4,
   "delayed_unassigned_shards" : 0,
   "number_of_pending_tasks" : 0,
   "number_of_in_flight_fetch" : 0,
   "task_max_waiting_in_queue_millis" : 0,
   "active_shards_percent_as_number" : 63.63636363636363
}

Cluster State

此 API 用于通过附加“state”关键字 URL 来获取有关群集的状态信息。状态信息包含版本、主节点、其他节点、路由表、元数据和块。

This API is used to get state information about a cluster by appending the ‘state’ keyword URL. The state information contains version, master node, other nodes, routing table, metadata and blocks.

GET /_cluster/state

在运行以上代码时，我们得到响应，如下所示：-

On running the above code, we get the response as shown below −

………………………………………………
{
   "cluster_name" : "elasticsearch",
   "cluster_uuid" : "IzKu0OoVTQ6LxqONJnN2eQ",
   "version" : 89,
   "state_uuid" : "y3BlwvspR1eUQBTo0aBjig",
   "master_node" : "FKH-5blYTJmff2rJ_lQOCg",
   "blocks" : { },
   "nodes" : {
      "FKH-5blYTJmff2rJ_lQOCg" : {
      "name" : "ubuntu",
      "ephemeral_id" : "426kTGpITGixhEzaM-5Qyg",
      "transport
   }
………………………………………………

Cluster Stats

此 API 有助于通过使用“stats”关键字检索有关群集的统计信息。此 API 返回分片数、存储大小、内存使用情况、节点数、角色、操作系统和文件系统。

This API helps to retrieve statistics about cluster by using the ‘stats’ keyword. This API returns shard number, store size, memory usage, number of nodes, roles, OS, and file system.

GET /_cluster/stats

在运行以上代码时，我们得到响应，如下所示：-

On running the above code, we get the response as shown below −

………………………………………….
"cluster_name" : "elasticsearch",
"cluster_uuid" : "IzKu0OoVTQ6LxqONJnN2eQ",
"timestamp" : 1556435464704,
"status" : "yellow",
"indices" : {
   "count" : 7,
   "shards" : {
      "total" : 7,
      "primaries" : 7,
      "replication" : 0.0,
      "index" : {
         "shards" : {
         "min" : 1,
         "max" : 1,
         "avg" : 1.0
      },
      "primaries" : {
         "min" : 1,
         "max" : 1,
         "avg" : 1.0
      },
      "replication" : {
         "min" : 0.0,
         "max" : 0.0,
         "avg" : 0.0
      }
………………………………………….

Cluster Update Settings

此 API 允许您通过使用“settings”关键字更新群集的设置。有两种类型的设置 - 持久性（在重启后应用）和瞬态（无法在完全群集重启后依然存在）。

This API allows you to update the settings of a cluster by using the ‘settings’ keyword. There are two types of settings − persistent (applied across restarts) and transient (do not survive a full cluster restart).

Node Stats

此 API 用于检索集群的一个或多个节点的统计信息。节点统计信息几乎与集群相同。

This API is used to retrieve the statistics of one more nodes of the cluster. Node stats are almost the same as cluster.

GET /_nodes/stats

在运行以上代码时，我们得到响应，如下所示：-

On running the above code, we get the response as shown below −

{
   "_nodes" : {
      "total" : 1,
      "successful" : 1,
      "failed" : 0
   },
   "cluster_name" : "elasticsearch",
   "nodes" : {
      "FKH-5blYTJmff2rJ_lQOCg" : {
         "timestamp" : 1556437348653,
         "name" : "ubuntu",
         "transport_address" : "127.0.0.1:9300",
         "host" : "127.0.0.1",
         "ip" : "127.0.0.1:9300",
         "roles" : [
            "master",
            "data",
            "ingest"
         ],
         "attributes" : {
            "ml.machine_memory" : "4112797696",
            "xpack.installed" : "true",
            "ml.max_open_jobs" : "20"
         },
………………………………………………………….

Nodes hot_threads

此 API 可帮助您检索集群中每个节点上当前热门线程的相关信息。

This API helps you to retrieve information about the current hot threads on each node in cluster.

GET /_nodes/hot_threads

在运行以上代码时，我们得到响应，如下所示：-

On running the above code, we get the response as shown below −

:::{ubuntu}{FKH-5blYTJmff2rJ_lQOCg}{426kTGpITGixhEzaM5Qyg}{127.0.0.1}{127.0.0.1:9300}{ml.machine_memory=4112797696,
xpack.installed=true, ml.max_open_jobs=20}
 Hot threads at 2019-04-28T07:43:58.265Z, interval=500ms, busiestThreads=3,
ignoreIdleThreads=true: