etcd的簡單使用

 

etcd的簡單使用

ETCD安裝配置

安裝

去https://github.com/coreos/etcd/releases/下載想要的版本解壓etcd包
解壓後進入目錄，增長x權限

chmod +x etcd 
chmod +x etcdctl

並將etcd和etcdctl 複製到 /bin

配置啓動

簡單啓動

./bin/etcd 這樣就能夠啓動使用

集羣配置

在兩臺機器上部署了簡單的集羣

192.168.231.130
192.168.231.132

在配置文件/etc/defalut/etcd 中增長：

ETCD_OPTS="-name infra0   -initial-advertise-peer-urls http://192.168.231.130:2380   -listen-peer-urls http://192.168.231.130:2380   -initial-cluster-
token etcd-cluster-1   -initial-cluster infra0=http://192.168.231.130:2380,infra1=http://192.168.231.132:2380   -initial-cluster-state new"

也可用參數的方法

ETCD_INITIAL_CLUSTER="infra0=http://192.168.231.130:2380,infra1=http://192.168.231.132:2380"
ETCD_INITIAL_CLUSTER_STATE=new

192.168.231.132機器上

ETCD_OPTS="-name infra1   -initial-advertise-peer-urls http://192.168.231.132:2380   -listen-peer-urls http://192.168.231.132:2380   -initial-cluster-token etcd-cluster-1   -initial-cluster infra0=http://192.168.231.130:2380,infra1=http://192.168.231.132:2380   -initial-cluster-state new"

 

參數解釋

啓動etcd進程後查看集羣

etcdctl member list
27e6981eec74137d: name=infra0 peerURLs=http://192.168.231.130:2380 clientURLs=http://localhost:2379,http://localhost:4001
3955a9b061e52de1: name=infra1 peerURLs=http://192.168.231.132:2380 clientURLs=http://localhost:2379,http://localhost:4001

 

判斷leader和followers

curl http://127.0.0.1:2379/v2/stats/leader

{"leader":"27e6981eec74137d","followers":{"3955a9b061e52de1":{"latency":{"current":0.178536,"average":0.26406266231884085,"standardDeviation":0.3787246458449882,"minimum":0.084328,"maximum":10.527117},"counts":{"fail":0,"success":1380}}}}

 

協議

簡單發送一個請求設置key值的請求

# curl -vvv http://127.0.0.1:2379/v2/keys/mykey -XPUT -d value="this is test"
* Hostname was NOT found in DNS cache
*   Trying 127.0.0.1...
* Connected to 127.0.0.1 (127.0.0.1) port 2379 (#0)
> PUT /v2/keys/mykey HTTP/1.1
> User-Agent: curl/7.35.0
> Host: 127.0.0.1:2379
> Accept: */*
> Content-Length: 18
> Content-Type: application/x-www-form-urlencoded
>
* upload completely sent off: 18 out of 18 bytes
< HTTP/1.1 200 OK
< Content-Type: application/json
< X-Etcd-Cluster-Id: 69bc358c20384a4c
< X-Etcd-Index: 16333
< X-Raft-Index: 87030
< X-Raft-Term: 117
< Date: Fri, 14 Aug 2015 01:39:39 GMT
< Content-Length: 201
<
{"action":"set","node":{"key":"/mykey","value":"this is test","modifiedIndex":16333,"createdIndex":16333},"prevNode":{"key":"/mykey","value":"this is test","modifiedIndex":14840,"createdIndex":14840}}
* Connection #0 to host 127.0.0.1 left intact

 

http接口是rest api的風格

body裏面字段詳解：

• action: set 操做對應的是url的put，rest api的風格
• node.key: 設置的key值
• node.value: 設置的value值
• node.createdIndex: 惟一的整數，每當etcd有改變時，這個值也會發生變化. 不只限於key值操做，包括增長和同步服務改變。這裏要修改
• node.modifiedIndex: 和createdIndex相似，也是一個惟一證整數 set , delete , update , create , - compareAndSwap ， compareAndDelete 這些操做都會改變這個值，而get和watch 命令不會修改改變這個值

header字段詳解：

X-Etcd-Cluster-Id: 69bc358c20384a4c
 X-Etcd-Index: 16333
 X-Raft-Index: 87030
 X-Raft-Term: 117

• X-Etcd-Index 等同於createdIndex.
• X-Etcd-Index is the current etcd index when the watch starts, which means that the watched event may happen after X-Etcd-Index
• X-Raft-Index 相似etcd index，可是用於raft protocol
• X-Raft-Term is an integer that will increase whenever an etcd master election happens in the cluster. If this number is increasing rapidly, you may need to tune the election timeout. See the tuning section for details.

可使用etcdctl簡化操做

# etcdctl get mykey
this is test

基本操做

可使用etcdctl或者url去執行手動操做
etcdctl幾個有用的附加命令

• –debug 將指令的url顯示出來

# etcdctl --debug get mykey
Cluster-Endpoints: http://localhost:2379, http://localhost:2379, http://localhost:4001, http://localhost:4001
Curl-Example: curl -X GET http://localhost:2379/v2/keys/mykey?consistent=true&recursive=false&sorted=false
this is test

 

• –output /-o 將輸出以指定的方式顯示出來

# etcdctl -o json get mykey 
{"action":"get","node":{"key":"/mykey","value":"12345","modifiedIndex":18134,"createdIndex":18134},"etcdIndex":18168,"raftIndex":96532,"raftTerm":124}

# etcdctl get mykey         
12345

 

查看版本

curl -L http://127.0.0.1:2379/version

etcdctl –version

# etcdctl --version
etcdctl version 2.0.13

 

設定鍵值

etcdctl set key value 
curl -X PUT http://localhost:2379/v2/keys/key -d value=value

 

如想要建立一個{mykey，kkkkk}的鍵值

# etcdctl --debug -o json set mykey kkkkk
Curl-Example: curl -X PUT http://localhost:2379/v2/keys/mykey -d value=kkkkk
{"action":"set","node":{"key":"/mykey","value":"kkkkk","modifiedIndex":21283,"createdIndex":21283},"prevNode":{"key":"/mykey","value":"kkkkk","modifiedIndex":20087,"createdIndex":20087},"etcdIndex":21283,"raftIndex":112958,"raftTerm":149}

# etcdctl --debug -o json get mykey
Curl-Example: curl -X GET http://localhost:2379/v2/keys/mykey?consistent=true&recursive=false&sorted=false
{"action":"get","node":{"key":"/mykey","value":"kkkkk","modifiedIndex":21283,"createdIndex":21283},"etcdIndex":21283,"raftIndex":112963,"raftTerm":149}

 

這裏顯示了前一個值，設置後再get返回的是最新的值
etcdctl mk key value也能起到建立並設置鍵值的做用，和set操做的區別主要是，不能對已存在的key進行建立的操做

# etcdctl --debug -o json mk aa 11
Curl-Example: curl -X PUT http://localhost:2379/v2/keys/aa?prevExist=false -d value=11
{"action":"create","node":{"key":"/aa","value":"11","modifiedIndex":21093,"createdIndex":21093},"etcdIndex":21093,"raftIndex":112010,"raftTerm":149}

# etcdctl --debug -o json mk aa 22
Curl-Example: curl -X PUT http://localhost:2379/v2/keys/aa?prevExist=false -d value=22
Error:  105: Key already exists (/aa) [21098]

 

查看鍵值

etcdctl get key 
curl -X GET http://localhost:2379/v2/keys/key?

etcdctl --debug -o json get mykey
Cluster-Endpoints: http://localhost:2379, http://localhost:2379, http://localhost:4001, http://localhost:4001
Curl-Example: curl -X GET http://localhost:2379/v2/keys/mykey?consistent=true&recursive=false&sorted=false
{"action":"get","node":{"key":"/mykey","value":"12345","modifiedIndex":18134,"createdIndex":18134},"etcdIndex":18661,"raftIndex":99095,"raftTerm":126}

 

查看鍵值

etcdctl rm key 
curl -X DELETE http://localhost:2379/v2/keys/key?

# etcdctl --debug -o json rm mykey
Cluster-Endpoints: http://localhost:2379, http://localhost:2379, http://localhost:4001, http://localhost:4001
Curl-Example: curl -X DELETE http://localhost:2379/v2/keys/mykey?dir=false&recursive=false
{"action":"delete","node":{"key":"/mykey","modifiedIndex":18766,"createdIndex":18701},"prevNode":{"key":"/mykey","value":"kkkkk","modifiedIndex":18701,"createdIndex":18701},"etcdIndex":18766,"raftIndex":99607,"raftTerm":127}

# etcdctl --debug -o json get mykey
Cluster-Endpoints: http://localhost:2379, http://localhost:2379, http://localhost:4001, http://localhost:4001
Curl-Example: curl -X GET http://localhost:2379/v2/keys/mykey?consistent=true&recursive=false&sorted=false
Error:  100: Key not found (/mykey) [18766]

 

設置鍵值的TTL

etcdctl set key value –ttl time
curl -X PUT http://localhost:2379/v2/keys/key -d value=value -d ttl=time
經過設置TTL可讓key值在規定時間過時，好比設置這個key的ttl爲100

 etcdctl --debug -o json set mykey ok --ttl 100
Cluster-Endpoints: http://localhost:2379, http://localhost:2379, http://localhost:4001, http://localhost:4001
Curl-Example: curl -X PUT http://localhost:2379/v2/keys/mykey -d value=ok -d ttl=100
{"action":"set","node":{"key":"/mykey","value":"ok","expiration":"2015-08-14T03:15:14.665295244Z","ttl":100,"modifiedIndex":19036,"createdIndex":19036},"etcdIndex":19036,"raftIndex":100957,"raftTerm":129}

 

過了幾十秒查看,ttl減爲23

# etcdctl --debug -o json get mykey
Cluster-Endpoints: http://localhost:2379, http://localhost:2379, http://localhost:4001, http://localhost:4001
Curl-Example: curl -X GET http://localhost:2379/v2/keys/mykey?consistent=true&recursive=false&sorted=false
{"action":"get","node":{"key":"/mykey","value":"ok","expiration":"2015-08-14T03:15:14.665295244Z","ttl":23,"modifiedIndex":19036,"createdIndex":19036},"etcdIndex":19077,"raftIndex":101148,"raftTerm":129}

 

當ttl減爲0，這個key值就查詢不到了

Error:  100: Key not found (/mykey) [19084]

 

目錄的ttl設置方法和key的相似

監控鍵值的改動

etcdctl watch key 
curl -X GET http://localhost:2379/v2/keys/key?consistent=true&wait=true 

 

監聽鍵值的改動，而後輸出信息， –after-index能夠根據etcd-index來獲取後續index對應的改動

etcdctl --debug watch mykey 
Cluster-Endpoints: http://localhost:2379, http://localhost:2379, http://localhost:4001, http://localhost:4001
Curl-Example: curl -X GET http://localhost:2379/v2/keys/mykey?consistent=true&wait=true

 

當監測到鍵值設置爲kkkkk時打印

kkkkk

 

若etcdctl watch 帶上–forever參數則會不退出一直監測鍵值的改動,好比這裏檢測到了set和delete操做

# etcdctl --debug -o json watch mykey --forever
Curl-Example: curl -X GET http://localhost:2379/v2/keys/mykey?consistent=true&wait=true


{"action":"set","node":{"key":"/mykey","value":"kkkkk","modifiedIndex":19656,"createdIndex":19656},"prevNode":{"key":"/mykey","value":"kkkkk","modifiedIndex":19645,"createdIndex":19645},"etcdIndex":19655,"raftIndex":104107,"raftTerm":131}


Curl-Example: curl -X GET http://localhost:2379/v2/keys/mykeyconsistent=true&wait=true&waitIndex=19657

{"action":"delete","node":{"key":"/mykey","modifiedIndex":19661,"createdIndex":19656},"prevNode":{"key":"/mykey","value":"kkkkk","modifiedIndex":19656,"createdIndex":19656},"etcdIndex":19656,"raftIndex":104115,"raftTerm":131}


Curl-Example: curl -X GET http://localhost:2379/v2/keys/mykey?consistent=true&wait=true&waitIndex=19662

 

對於目錄類型的key能夠用–recursive 來檢測目錄下的子keys的改動

一樣能夠用做監測的命令是exec-watch，相比watch，增長了監測到改動能夠執行自定義的操做
etcdctl watch key command

# etcdctl exec-watch mykey -- sh -c 'echo hit'
hit

 

目錄相關的操做

etcdctl mkdir dirname

建立一個目錄能夠關聯多個子keys，好比先創建一個名叫mydir的dir

etcdctl --debug -o json mkdir mydir 
Curl-Example: curl -X PUT http://localhost:2379/v2/keys/mydir?dir=true&prevExist=false

 

在這個dir下面能夠創建多個keys

# etcdctl --debug -o json set /mydir/key1 11111
Curl-Example: curl -X PUT http://localhost:2379/v2/keys/mydir/key1 -d value=11111
{"action":"set","node":{"key":"/mydir/key1","value":"11111","modifiedIndex":20850,"createdIndex":20850},"etcdIndex":20850,"raftIndex":110723,"raftTerm":148}

# etcdctl --debug -o json set /mydir/key2 22222
Curl-Example: curl -X PUT http://localhost:2379/v2/keys/mydir/key2 -d value=22222
{"action":"set","node":{"key":"/mydir/key2","value":"22222","modifiedIndex":20855,"createdIndex":20855},"etcdIndex":20855,"raftIndex":110747,"raftTerm":148}

 

能夠用etcdctl ls dirname進行查看，獲得該dir下面的2個key

# etcdctl --debug -o json ls /mydir
Curl-Example: curl -X GET http://localhost:2379/v2/keys/mydir?consistent=true&recursive=false&sorted=false
/mydir/key2
/mydir/key1

 

若是向目錄名的路徑 post一個value，那麼在這個目錄下面會自動用createdIndex建立一個key

# curl -X POST http://localhost:2379/v2/keys/mydir -d value=33333
{"action":"create","node":{"key":"/mydir/21442","value":"33333","modifiedIndex":21442,"createdIndex":21442}}

# etcdctl --debug -o json ls /mydir
Curl-Example: curl -X GET http://localhost:2379/v2/keys/mydir?consistent=true&recursive=false&sorted=false
/mydir/key1
/mydir/key2
/mydir/21442

 

用rmdir 刪除目錄要保證目錄下沒有keys，否則會失敗

# etcdctl --debug -o json rmdir mydir
Curl-Example: curl -X DELETE http://localhost:2379/v2/keys/mydir?dir=true&recursive=false
Error:  108: Directory not empty (/mydir) [21682]

 

若要將目錄和keys都刪除能夠用rm指令

# etcdctl --debug -o json rm mydir --recursive=true
Curl-Example: curl -X DELETE http://localhost:2379/v2/keys/mydir?dir=false&recursive=true

# etcdctl --debug -o json ls /mydir
Curl-Example: curl -X GET http://localhost:2379/v2/keys/mydir?consistent=true&recursive=false&sorted=false
Error:  100: Key not found (/mydir) [21883]

 

狀態查看

etcd分別提供了查看leader、本身以及store狀態的接口

• 查看leader的狀態

curl http://127.0.0.1:2379/v2/stats/leader
{"leader":"27e6981eec74137d","followers":{"3955a9b061e52de1":{"latency":{"current":0.158241,"average":0.22540039942528703,"standardDeviation":0.17653730983599686,"minimum":0.087808,"maximum":1.988291},"counts":{"fail":0,"success":348}}}}

 

• 查看本身的狀態

curl http://127.0.0.1:2379/v2/stats/self
# curl http://127.0.0.1:2379/v2/stats/self
{"name":"infra0","id":"27e6981eec74137d","state":"StateLeader","startTime":"2015-08-14T12:52:39.624477849+08:00","leaderInfo":{"leader":"27e6981eec74137d","uptime":"2m37.095030303s","startTime":"2015-08-14T12:55:31.332765166+08:00"},"recvAppendRequestCnt":429,"sendAppendRequestCnt":1064,"sendPkgRate":6.896118337343223,"sendBandwidthRate":1170.6850489473857}

 

• 查看store的狀態

curl http://127.0.0.1:2379/v2/stats/store 
{"getsSuccess":13,"getsFail":2152,"setsSuccess":120,"setsFail":2,"deleteSuccess":6,"deleteFail":0,"updateSuccess":0,"updateFail":0,"createSuccess":961,"createFail":186,"compareAndSwapSuccess":19631,"compareAndSwapFail":296,"compareAndDeleteSuccess":0,"compareAndDeleteFail":0,"expireCount":849,"watchers":0}

 

其餘接口以及更詳盡的接口說明能夠看官網說明