1、_cat列入所有有效命令
GET /_cat
返回：有个猫...所以不难想象为啥是cat api
=^.^=
/_cat/allocation
/_cat/shards
/_cat/shards/{index}
/_cat/master
/_cat/nodes
/_cat/tasks
/_cat/indices
/_cat/indices/{index}
/_cat/segments
/_cat/segments/{index}
/_cat/count
/_cat/count/{index}
/_cat/recovery
/_cat/recovery/{index}
/_cat/health
/_cat/pending_tasks
/_cat/aliases
/_cat/aliases/{alias}
/_cat/thread_pool
/_cat/thread_pool/{thread_pools}
/_cat/plugins
/_cat/fielddata
/_cat/fielddata/{fields}
/_cat/nodeattrs
/_cat/repositories
/_cat/snapshots/{repository}
/_cat/templates
2、通用参数
2.1 verbose参数，显示命令详细信息
GET /_cat/master?v result: id host ip node Sa5md_zERDebxloO004ffQ 192.168.31.10 192.168.31.10 vmstation.es.1 没有加?v的情况，result： Sa5md_zERDebxloO004ffQ 192.168.31.10 192.168.31.10 vmstation.es.1
2.2 help参数，显示有效列的详细说明
GET /_cat/master?help result: id | | node id host | h | host name ip | | ip address node | n | node name
2.3 header参数，选择显示的列
GET /_cat/nodes?h=ip,port,heapPercent,name result: 192.168.31.10 9300 43 vmstation.es.1
2.4、响应体返回格式，支持json,yaml,text(default),smile,cbor
json格式
GET /_cat/indices?format=json&pretty result: [ { "health" : "green", "status" : "open", "index" : ".monitoring-kibana-6-2018.12.24", "uuid" : "vkJltBs1T8qEfdUDdyDYzA", "pri" : "1", "rep" : "0", "docs.count" : "1345", "docs.deleted" : "0", "store.size" : "453.3kb", "pri.store.size" : "453.3kb" }, { "health" : "green", "status" : "open", "index" : "user2", "uuid" : "xo9Zb2OkRWeqV5bRKNDKGg", "pri" : "1", "rep" : "0", "docs.count" : "12", "docs.deleted" : "0", "store.size" : "7.9kb", "pri.store.size" : "7.9kb" }, ..... ]
2.5、多个参数混合使用，一个问号，参数用&连接
GET /_cat/nodes?v&h=ip,port,heapPercent,name result: ip port heapPercent name 192.168.31.10 9300 59 vmstation.es.1
2.6、排序sort，缺省是asc排序
GET /_cat/indices?v&h=health,index,store.size&s=store.size:desc result: health index store.size green .monitoring-es-6-2018.12.24 10mb green .monitoring-es-6-2018.12.20 5mb green .monitoring-es-6-2018.12.25 4.4mb green .monitoring-kibana-6-2018.12.24 453.3kb green .monitoring-kibana-6-2018.12.20 318kb green .monitoring-kibana-6-2018.12.25 195.2kb yellow bus 86kb yellow blog 34.3kb green shirts 25kb yellow home 16.8kb green user 13.7kb green .kibana_1 12kb green bus2 11.6kb green user2 7.9kb green user3 261b
多个字段排序： GET /_cat/indices?v&h=health,index,store.size,pri.store.size&s=store.size:desc,pri.store.size:desc result： health index store.size pri.store.size green .monitoring-es-6-2018.12.24 10mb 10mb green .monitoring-es-6-2018.12.20 5mb 5mb green .monitoring-es-6-2018.12.25 4.6mb 4.6mb green .monitoring-kibana-6-2018.12.24 453.3kb 453.3kb green .monitoring-kibana-6-2018.12.20 318kb 318kb green .monitoring-kibana-6-2018.12.25 202.4kb 202.4kb yellow bus 86kb 86kb yellow blog 34.3kb 34.3kb green shirts 25kb 25kb yellow home 16.8kb 16.8kb green user 13.7kb 13.7kb green .kibana_1 12kb 12kb green bus2 11.6kb 11.6kb green user2 7.9kb 7.9kb green user3 261b 261b
3、aliases显示别名、过滤器、路由信息
GET /_cat/aliases?v result: alias index filter routing.index routing.search .kibana .kibana_1 - - -
4、allocation显示每个数据节点分配多少碎片以及它们使用多少磁盘空间的快照
GET /_cat/allocation?v&format=json
result：
[
{
"shards" : "20",
"disk.indices" : "21.4mb",
"disk.used" : "4gb",
"disk.avail" : "12.9gb",
"disk.total" : "16.9gb",
"disk.percent" : "23",
"host" : "192.168.31.10",
"ip" : "192.168.31.10",
"node" : "vmstation.es.1"
},
{
"shards" : "7",
"disk.indices" : null,
"disk.used" : null,
"disk.avail" : null,
"disk.total" : null,
"disk.percent" : null,
"host" : null,
"ip" : null,
"node" : "UNASSIGNED"
}
]
#7个碎片是曾经属于一个集群，现在只有单节点，但是索引建立的时候使用它作为副本，所以信息都是未知的。
5、count显示所有索引或者某个索引的文档数量
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GET /_cat/count?v result: epoch timestamp count 1545709338 03:42:18 47638
或者单个索引
GET /_cat/count/bus?v result: epoch timestamp count 1545709383 03:43:03 27
6、fielddata
GET /_cat/fielddata?v result: id host ip node field size Sa5md_zERDebxloO004ffQ 192.168.31.10 192.168.31.10 vmstation.es.1 type 552b
7、indices显示每个索引的横截面。此信息跨越节点。
GET /_cat/indices?v result: health status index uuid pri rep docs.count docs.deleted store.size pri.store.size green open .monitoring-kibana-6-2018.12.24 vkJltBs1T8qEfdUDdyDYzA 1 0 1345 0 453.3kb 453.3kb green open user2 xo9Zb2OkRWeqV5bRKNDKGg 1 0 12 0 7.9kb 7.9kb yellow open bus G4DrNdPhRWK_rBuEaluwsA 3 1 27 3 86kb 86kb green open .monitoring-es-6-2018.12.25 Gl01crYyQImkxCTGvB3Xkg 1 0 16845 189 15.6mb 15.6mb green open shirts NLF5tjIuSz-JbUQcc_VbiQ 1 0 7 0 25kb 25kb green open .monitoring-kibana-6-2018.12.20 GRwFygbPRw62Qeoyg-68Mg 1 0 719 0 318kb 318kb green open .monitoring-kibana-6-2018.12.25 TmCzVC4wQrmmElX8Bbmjdg 1 0 866 0 710.2kb 710.2kb green open .monitoring-es-6-2018.12.20 IH3moZNyQfCHp8ZUjelmWA 1 0 9548 215 5mb 5mb yellow open home CSyKu2FJTZGtSIg0jOltcw 2 1 7 0 16.8kb 16.8kb green open .monitoring-es-6-2018.12.24 jCgptARpQ8S-B3Gn8adYSQ 1 0 23936 25 10mb 10mb yellow open blog G7leckf1RQGHNCZKROpBCg 2 1 33 6 34.3kb 34.3kb green open .kibana_1 olE1g78PTl-FxApa5LXhtg 1 0 3 0 12kb 12kb green open user3 -ArWuP3ZRsGsoiLwMxRyKQ 1 0 0 0 261b 261b green open bus2 j2ckAmxCRjuH6xVCU1aATA 1 0 27 0 11.6kb 11.6kb green open user WdRH_r9DSDOtySMxlRYe_g 2 0 12 0 13.7kb 13.7kb
单个索引（支持通配符）：
GET /_cat/indices/bus*?v&h=index,status,pri,rep,docs.count result: index status pri rep docs.count bus2 open 1 0 27 bus open 3 1 27
或者
GET /_cat/indices?v&index=bus*