01-Elasticsearch API - 集群操作

简单集群操作

查看节点信息

GET /?pretty

//result
{
  "name": "sqmcQNC", //节点名
  "cluster_name": "elasticsearch", //集群名
  "cluster_uuid": "Xar4EVm2QaW92vWL0tj5AA",
  "version": {
    "number": "5.5.0",
    "build_hash": "260387d",
    "build_date": "2017-06-30T23:16:05.735Z",
    "build_snapshot": false,
    "lucene_version": "6.6.0"
  },
  "tagline": "You Know, for Search"
}

检查集群健康状况

GET /_cluster/health

//result
{
  "cluster_name": "elasticsearch",
  "status": "yellow",
  "timed_out": false,
  "number_of_nodes": 1,
  "number_of_data_nodes": 1,
  "active_primary_shards": 6,
  "active_shards": 6,
  "relocating_shards": 0,
  "initializing_shards": 0,
  "unassigned_shards": 6,
  "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": 50
}

GET /_cat/health?v

//result
epoch      timestamp cluster       status node.total node.data shards pri relo init unassign pending_tasks max_task_wait_time active_shards_percent
1500427656 09:27:36  elasticsearch yellow          1         1      1   1    0    0        1             0                  -                 50.0%

status表示集群的健康状态：
green：每个索引的primary shard和replica shard都是active状态的
yellow：每个索引的primary shard都处于active状态，但是部分replica shard不是active状态，处于不可用状态
red：不是所有索引的primary shard都处于active状态，部分索引有数据丢失

目前处于yellow状态是因为我们现在就启动了一个es进程，相当于就只有一个node。现在es中有一个index，就是kibana自己内置建立的index。由于默认的配置是给每个index分配5个primary shard和5个replica shard，而且primary shard和replica shard不能在同一台机器上（为了容错）。现在kibana自己建立的index是1个primary shard和1个replica shard。当前就一个node，所以只有1个primary shard被分配了和启动了，但是一个replica shard没有第二台机器去启动。

快速获取集群中有那些索引

GET /_cat/indices?v

//result
health status index   uuid                   pri rep docs.count docs.deleted store.size pri.store.size
yellow open   .kibana 1YPy2F8hQ9ymtYh3XbEhQQ   1   1          1            0      3.2kb          3.2kb