开篇
作为一个elasticsearch的新手，我觉得elasticsearch的官网的文档归类清楚，作为新手很有必要多阅读几次，每次都能加深印象。这里作为个人理解进行一些简单的归类便于查阅。
对于新手而言，熟悉各类能够掌握简单的操作包括：索引的创建删除查询，文档的增删改查、集群信息查询等。
- Indices APIs：负责索引Index的创建（create）、删除（delete）、获取（get）、索引存在（exist）等操作。
- Document APIs：负责索引文档的创建（index）、删除（delete）、获取（get）等操作。
- Search APIs：负责索引文档的search（查询），Document APIS根据doc_id进行查询，Search APIs]根据条件查询。
- Aggregations：负责针对索引的文档各维度的聚合（Aggregation）。
- cat APIs：负责查询索引相关的各类信息查询。
- Cluster APIs：负责集群相关的各类信息查询。
提供一个操作的方法，就是本机搭建个es集群然后部署一个kibana，通过kibana熟悉http api就可以了，这篇文章就专注下cat和cluster相关的api。
cat APIs介绍
说明：
aliases 负责展示当前es集群配置别名包括filter和routing信息。
命令：
GET /_cat/aliases?v
GET /_cat/aliases/alias1,alias2
返回：
alias index filter routing.index routing.search
alias1 test1 - - -
alias2 test1 * - -
alias3 test1 - 1 1
alias4 test1 - 2 1,2说明：
allocation负责展示es的每个数据节点分配的索引分片以及使用的磁盘空间。
命令：
GET /_cat/allocation?v
返回值：
shards disk.indices disk.used disk.avail disk.total disk.percent host ip node
5 260b 47.3gb 43.4gb 100.7gb 46 127.0.0.1 127.0.0.1 CSUXak2说明：
count负责展示整个ES集群或者单个索引的文档数。
命令：
GET /_cat/count?v
GET /_cat/count/twitter?v
返回值：
epoch timestamp count
1475868259 15:24:20 120说明：
fielddata负责展示ES集群每个数据节点中fileddata占用的堆内存。
命令：
GET /_cat/fielddata?v
GET /_cat/fielddata?v&fields=body
GET /_cat/fielddata/body,soul?v
返回值：
id host ip node field size
Nqk-6inXQq-OxUfOUI8jNQ 127.0.0.1 127.0.0.1 Nqk-6in body 544b
Nqk-6inXQq-OxUfOUI8jNQ 127.0.0.1 127.0.0.1 Nqk-6in soul 480b说明：
health负责展示集群的健康状态
命令：
GET /_cat/health?v
GET /_cat/health?v&ts=false
返回值：
epoch timestamp cluster status node.total node.data shards pri relo init unassign pending_tasks max_task_wait_time active_shards_percent
1475871424 16:17:04 elasticsearch green 1 1 5 5 0 0 0 0 - 100.0%说明：
indices负责提供索引的相关信息，包括组成一个索引（index）的shard、document的数量，删除的doc数量，主存大小和所有索引的总存储大小。
命令：
GET /_cat/indices/twi*?v&s=index
返回值：
health status index uuid pri rep docs.count docs.deleted store.size pri.store.size
yellow open twitter u8FNjxh8Rfy_awN11oDKYQ 1 1 1200 0 88.1kb 88.1kb
green open twitter2 nYFWZEO7TUiOjLQXBaYJpA 5 0 0 0 260b 260b
说明：
master负责展示es集群的master节点信息包括节点id、节点名、ip地址等。
命令：
GET /_cat/master?v
返回值：
id host ip node
YzWoH_2BT-6UjVGDyPdqYg 127.0.0.1 127.0.0.1 YzWoH_2说明：
nodeattrs负责展示通用的节点信息。
命令：
GET /_cat/nodeattrs?v
返回值：
node host ip attr value
node-0 127.0.0.1 127.0.0.1 testattr test说明：
nodes负责展示es集群的拓扑信息。
命令：
GET /_cat/nodes?v
返回值：
ip heap.percent ram.percent cpu load_1m load_5m load_15m node.role master name
127.0.0.1 65 99 42 3.07 mdi * mJw06l1
说明：
pending_tasks返回集群层面的未执行的任务列表包括创建索引，更新mapping，allocate分片信息。
命令：
GET /_cat/pending_tasks?v
返回值：
insertOrder timeInQueue priority source
1685 855ms HIGH update-mapping [foo][t]
1686 843ms HIGH update-mapping [foo][t]
1693 753ms HIGH refresh-mapping [foo][[t]]
1688 816ms HIGH update-mapping [foo][t]
1689 802ms HIGH update-mapping [foo][t]
1690 787ms HIGH update-mapping [foo][t]
1691 773ms HIGH update-mapping [foo][t]说明：
plugins命令展示每个节点正在运行的插件信息。
命令：
GET /_cat/plugins?v&s=component&h=name,component,version,description
返回值：
name component version description
U7321H6 analysis-icu 6.5.4 The ICU Analysis plugin integrates Lucene ICU module into elasticsearch, adding ICU relates analysis components.
U7321H6 analysis-kuromoji 6.5.4 The Japanese (kuromoji) Analysis plugin integrates Lucene kuromoji analysis module into elasticsearch.
U7321H6 analysis-nori 6.5.4 The Korean (nori) Analysis plugin integrates Lucene nori analysis module into elasticsearch.
U7321H6 analysis-phonetic 6.5.4 The Phonetic Analysis plugin integrates phonetic token filter analysis with elasticsearch.说明：
recovery命令展示索引分片恢复，包括正在进行的和已经完成的任务。
命令：
GET _cat/recovery?v
GET _cat/recovery?v&h=i,s,t,ty,st,shost,thost,f,fp,b,bp
返回值：
index shard time type stage source_host source_node target_host target_node repository snapshot files files_recovered files_percent files_total bytes bytes_recovered bytes_percent bytes_total translog_ops translog_ops_recovered translog_ops_percent
twitter 0 13ms store done n/a n/a 127.0.0.1 node-0 n/a n/a 0 0 100% 13 0 0 100% 9928 0 0 100.0%说明：
repositories命令展示在集群中注册的快照仓库。
命令：
GET /_cat/repositories?v
GET /_cat/thread_pool/generic?v&h=id,name,active,rejected,completed
返回值：
id type
repo1 fs
repo2 s3
说明：
thread_pool命令展示集群节点的线程池的统计信息，包括处于活跃、队列等待、拒绝的线程任务信息。
命令：
GET /_cat/thread_pool
返回值：
node-0 bulk 0 0 0
node-0 fetch_shard_started 0 0 0
node-0 fetch_shard_store 0 0 0
node-0 flush 0 0 0
node-0 force_merge 0 0 0
node-0 generic 0 0 0
node-0 get 0 0 0
node-0 index 0 0 0
node-0 listener 0 0 0
node-0 management 1 0 0
node-0 refresh 0 0 0
node-0 search 0 0 0
node-0 snapshot 0 0 0
node-0 warmer 0 0 0说明：
shards命令展示每个节点包括哪些分片信息。
命令：
GET _cat/shards
GET _cat/shards/twitt*
返回值：
twitter 0 p STARTED 3014 31.1mb 192.168.56.10 H5dfFeA说明：
segments命令展示索引的segments的信息。
命令：
GET /_cat/segments?v
返回值：
index shard prirep ip segment generation docs.count docs.deleted size size.memory committed searchable version compound
test 3 p 127.0.0.1 _0 0 1 0 3kb 2042 false true 7.1.0 true
test1 3 p 127.0.0.1 _0 0 1 0 3kb 2042 false true 7.1.0 true
说明：
snapshots命令展示属于某个指定快照仓库的所有快照信息。通过/_cat/repositories查找所有的仓库列表。
命令：
GET /_cat/snapshots/repo1?v&s=id
返回值：
id status start_epoch start_time end_epoch end_time duration indices successful_shards failed_shards total_shards
snap1 FAILED 1445616705 18:11:45 1445616978 18:16:18 4.6m 1 4 1 5
snap2 SUCCESS 1445634298 23:04:58 1445634672 23:11:12 6.2m 2 10 0 10
说明：
templates展示已存在的模板信息。
命令：
GET /_cat/templates?v&s=name
返回值：
name index_patterns order version
template0 [te*] 0
template1 [tea*] 1
template2 [teak*] 2 7Cluster APIs介绍
说明：
health命令展示集群的健康状态，
命令：
GET _cluster/health
GET /_cluster/health/test1,test2
返回值：
{
"cluster_name" : "testcluster",
"status" : "yellow",
"timed_out" : false,
"number_of_nodes" : 1,
"number_of_data_nodes" : 1,
"active_primary_shards" : 5,
"active_shards" : 5,
"relocating_shards" : 0,
"initializing_shards" : 0,
"unassigned_shards" : 5,
"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": 50.0
}说明：
state命令展示集群详细的状态信息，
其中metrics指标包括version、master_node、nodes、routing_table、metadata、blocks。
命令：
GET /_cluster/state
GET /_cluster/state/{metrics}/{indices}
GET /_cluster/state/metadata,routing_table/foo,bar
返回值：
{
"cluster_name": "my-application",
"compressed_size_in_bytes": 847,
"version": 10,
"state_uuid": "DDWoFtm7TvCydbp8SKRQdw",
"master_node": "YOIwJR1bTxG0iKHur_M-Rg"
}说明：
Stats命令展示集群的多维度统计信息。
指标包括shard numbers, store size, memory usage、
number, roles, os, jvm versions, memory usage, cpu and installed plugins。
命令：
GET /_cluster/stats?human&pretty
返回值：
{
"_nodes" : {
"total" : 1,
"successful" : 1,
"failed" : 0
},
"cluster_name": "elasticsearch",
"timestamp": 1459427693515,
"status": "green",
"indices": {
"count": 1,
"shards": {
"total": 5,
"primaries": 5,
"replication": 0,
"index": {
"shards": {
"min": 5,
"max": 5,
"avg": 5
},
"primaries": {
"min": 5,
"max": 5,
"avg": 5
},
"replication": {
"min": 0,
"max": 0,
"avg": 0
}
}
},
"docs": {
"count": 10,
"deleted": 0
},
"store": {
"size": "16.2kb",
"size_in_bytes": 16684
},
"fielddata": {
"memory_size": "0b",
"memory_size_in_bytes": 0,
"evictions": 0
},
"query_cache": {
"memory_size": "0b",
"memory_size_in_bytes": 0,
"total_count": 0,
"hit_count": 0,
"miss_count": 0,
"cache_size": 0,
"cache_count": 0,
"evictions": 0
},
"completion": {
"size": "0b",
"size_in_bytes": 0
},
"segments": {
"count": 4,
"memory": "8.6kb",
"memory_in_bytes": 8898,
"terms_memory": "6.3kb",
"terms_memory_in_bytes": 6522,
"stored_fields_memory": "1.2kb",
"stored_fields_memory_in_bytes": 1248,
"term_vectors_memory": "0b",
"term_vectors_memory_in_bytes": 0,
"norms_memory": "384b",
"norms_memory_in_bytes": 384,
"points_memory" : "0b",
"points_memory_in_bytes" : 0,
"doc_values_memory": "744b",
"doc_values_memory_in_bytes": 744,
"index_writer_memory": "0b",
"index_writer_memory_in_bytes": 0,
"version_map_memory": "0b",
"version_map_memory_in_bytes": 0,
"fixed_bit_set": "0b",
"fixed_bit_set_memory_in_bytes": 0,
"max_unsafe_auto_id_timestamp" : -9223372036854775808,
"file_sizes": {}
}
},
"nodes": {
"count": {
"total": 1,
"data": 1,
"coordinating_only": 0,
"master": 1,
"ingest": 1
},
"versions": [
"6.1.4"
],
"os": {
"available_processors": 8,
"allocated_processors": 8,
"names": [
{
"name": "Mac OS X",
"count": 1
}
],
"mem" : {
"total" : "16gb",
"total_in_bytes" : 17179869184,
"free" : "78.1mb",
"free_in_bytes" : 81960960,
"used" : "15.9gb",
"used_in_bytes" : 17097908224,
"free_percent" : 0,
"used_percent" : 100
}
},
"process": {
"cpu": {
"percent": 9
},
"open_file_descriptors": {
"min": 268,
"max": 268,
"avg": 268
}
},
"jvm": {
"max_uptime": "13.7s",
"max_uptime_in_millis": 13737,
"versions": [
{
"version": "1.8.0_74",
"vm_name": "Java HotSpot(TM) 64-Bit Server VM",
"vm_version": "25.74-b02",
"vm_vendor": "Oracle Corporation",
"count": 1
}
],
"mem": {
"heap_used": "57.5mb",
"heap_used_in_bytes": 60312664,
"heap_max": "989.8mb",
"heap_max_in_bytes": 1037959168
},
"threads": 90
},
"fs": {
"total": "200.6gb",
"total_in_bytes": 215429193728,
"free": "32.6gb",
"free_in_bytes": 35064553472,
"available": "32.4gb",
"available_in_bytes": 34802409472
},
"plugins": [
{
"name": "analysis-icu",
"version": "6.1.4",
"description": "The ICU Analysis plugin integrates Lucene ICU module into elasticsearch, adding ICU relates analysis components.",
"classname": "org.elasticsearch.plugin.analysis.icu.AnalysisICUPlugin",
"has_native_controller": false
},
{
"name": "ingest-geoip",
"version": "6.1.4",
"description": "Ingest processor that uses looksup geo data based on ip adresses using the Maxmind geo database",
"classname": "org.elasticsearch.ingest.geoip.IngestGeoIpPlugin",
"has_native_controller": false
},
{
"name": "ingest-user-agent",
"version": "6.1.4",
"description": "Ingest processor that extracts information from a user agent",
"classname": "org.elasticsearch.ingest.useragent.IngestUserAgentPlugin",
"has_native_controller": false
}
],
"network_types" : {
"transport_types" : {
"netty4" : 1
},
"http_types" : {
"netty4" : 1
}
}
}
}
说明：
pending_tasks返回集群级别的未执行的任务，
包括创建索引,、更新mapping、 分配分片等。
命令：
ET /_cluster/pending_tasks
返回值：
{
"tasks": [
{
"insert_order": 101,
"priority": "URGENT",
"source": "create-index [foo_9], cause [api]",
"time_in_queue_millis": 86,
"time_in_queue": "86ms"
},
{
"insert_order": 46,
"priority": "HIGH",
"source": "shard-started ([foo_2][1], node[tMTocMvQQgGCkj7QDHl3OA], [P], s[INITIALIZING]), reason [after recovery from shard_store]",
"time_in_queue_millis": 842,
"time_in_queue": "842ms"
},
{
"insert_order": 45,
"priority": "HIGH",
"source": "shard-started ([foo_2][0], node[tMTocMvQQgGCkj7QDHl3OA], [P], s[INITIALIZING]), reason [after recovery from shard_store]",
"time_in_queue_millis": 858,
"time_in_queue": "858ms"
}
]
}说明：
reroute命令允许我们人工的重新分配集群中的索引分片。
move：移动分片
cancel：取消分片分配
allocate_replica：分配副本
命令：
POST /_cluster/reroute
{
"commands" : [
{
"move" : {
"index" : "test", "shard" : 0,
"from_node" : "node1", "to_node" : "node2"
}
},
{
"allocate_replica" : {
"index" : "test", "shard" : 1,
"node" : "node3"
}
}
]
}说明：
更新集群的配置信息并返回执行更新完成的配置。
命令：
PUT /_cluster/settings
{
"persistent" : {
"indices.recovery.max_bytes_per_sec" : "50mb"
}
}
PUT /_cluster/settings?flat_settings=true
{
"transient" : {
"indices.recovery.max_bytes_per_sec" : "20mb"
}
}
返回值：
{
...
"persistent" : { },
"transient" : {
"indices.recovery.max_bytes_per_sec" : "20mb"
}
}说明：
_nodes/stats 展示集群中指定节点或所有节点的统计信息。
命令：
GET /_nodes/stats
GET /_nodes/nodeId1,nodeId2/stats
返回值：
{
"_nodes": {
"total": 1,
"successful": 1,
"failed": 0
},
"cluster_name": "my-application",
"nodes": {
"YOIwJR1bTxG0iKHur_M-Rg": {
"timestamp": 1545564028595,
"name": "node-2",
"transport_address": "127.0.0.1:9300",
"host": "127.0.0.1",
"ip": "127.0.0.1:9300",
"roles": [
"master",
"data",
"ingest"
],
"os": {
"timestamp": 1545564028595,
"cpu": {
"percent": 12,
"load_average": {
"1m": 1.7255859375
}
},
"mem": {
"total_in_bytes": 8589934592,
"free_in_bytes": 305328128,
"used_in_bytes": 8284606464,
"free_percent": 4,
"used_percent": 96
},
"swap": {
"total_in_bytes": 2147483648,
"free_in_bytes": 1657012224,
"used_in_bytes": 490471424
}
}
}
}
}说明：
_nodes展示集群中每个节点的信息。
命令：
GET /_nodes
GET /_nodes/nodeId1,nodeId2
指标包括settings, os, process, jvm, thread_pool, transport, http, plugins, ingest，indices
返回值：
{
"_nodes": {
"total": 1,
"successful": 1,
"failed": 0
},
"cluster_name": "my-application",
"nodes": {
"YOIwJR1bTxG0iKHur_M-Rg": {
"name": "node-2",
"transport_address": "127.0.0.1:9300",
"host": "127.0.0.1",
"ip": "127.0.0.1",
"version": "6.1.0",
"build_hash": "c0c1ba0",
"roles": [
"master",
"data",
"ingest"
],
"os": {
"refresh_interval_in_millis": 1000,
"name": "Mac OS X",
"arch": "x86_64",
"version": "10.14.2",
"available_processors": 4,
"allocated_processors": 4
}
}
}
}说明：
_nodes/usage展示集群各个节点各类服务调用次数
命令：
GET _nodes/usage
GET _nodes/nodeId1,nodeId2/usage
返回值：
{
"_nodes": {
"total": 1,
"successful": 1,
"failed": 0
},
"cluster_name": "my_cluster",
"nodes": {
"pQHNt5rXTTWNvUgOrdynKg": {
"timestamp": 1492553961812,
"since": 1492553906606,
"rest_actions": {
"org.elasticsearch.rest.action.admin.cluster.RestNodesUsageAction": 1,
"org.elasticsearch.rest.action.admin.indices.RestCreateIndexAction": 1,
"org.elasticsearch.rest.action.document.RestGetAction": 1,
"org.elasticsearch.rest.action.search.RestSearchAction": 19,
"org.elasticsearch.rest.action.admin.cluster.RestNodesInfoAction": 36
}
}
}
}说明：
返回集群的连接信息。
命令：
GET /_remote/info说明：
_nodes/hot_threads展示集群节点的热点线程信息。
命令：
GET /_nodes/hot_threads
GET /_nodes/{nodesIds}/hot_threads.
返回值：
::: {node-2}{YOIwJR1bTxG0iKHur_M-Rg}{UmVpL8zQTUa1tu6TtOhpyQ}{127.0.0.1}{127.0.0.1:9300}
Hot threads at 2018-12-23T12:22:24.368Z, interval=500ms, busiestThreads=3, ignoreIdleThreads=true:Cluster Allocation Explain API
说明：
用于解释分片没有被分配的原因
命令：
GET /_cluster/allocation/explain
{
"index": "myindex",
"shard": 0,
"primary": true
}
返回值：
{
"index" : "idx",
"shard" : 0,
"primary" : true,
"current_state" : "unassigned",
"unassigned_info" : {
"reason" : "INDEX_CREATED",
"at" : "2017-01-04T18:08:16.600Z",
"last_allocation_status" : "no"
},
"can_allocate" : "no",
"allocate_explanation" : "cannot allocate because allocation is not permitted to any of the nodes",
"node_allocation_decisions" : [
{
"node_id" : "8qt2rY-pT6KNZB3-hGfLnw",
"node_name" : "node-0",
"transport_address" : "127.0.0.1:9401",
"node_attributes" : {},
"node_decision" : "no",
"weight_ranking" : 1,
"deciders" : [
{
"decider" : "filter",
"decision" : "NO",
"explanation" : "node does not match index setting [index.routing.allocation.include] filters [_name:\"non_existent_node\"]"
}
]
}
]
}
