consul服務發現與註冊於配置 (mac版為例)

阿新 • • 發佈：2019-02-13

consul 介紹

Consul是HashiCorp公司推出的開源工具，用於實現分散式系統的服務發現與配置。與其他分散式服務註冊與發現的方案，比如 Airbnb的SmartStack等相比，Consul的方案更“一站式”，內建了服務註冊與發現框架、分佈一致性協議實現、健康檢查、Key/Value儲存、多資料中心方案，不再需要依賴其他工具（比如ZooKeeper等）。使用起來也較為簡單。Consul用Golang實現，因此具有天然可移植性(支援Linux、windows和Mac OS X)；安裝包僅包含一個可執行檔案，方便部署，與Docker等輕量級容器可無縫配合。
gitHub: https://github.com/hashicorp/consul

官網：https://www.consul.io/
官方說明：https://www.consul.io/docs/index.html
go api: https://godoc.org/github.com/hashicorp/consul/api
golang API 程式碼位置:https://github.com/hashicorp/consul/tree/master/api

consul 目錄或檔案說明

/tmp/consul: 資料儲存
/Users/fox/bin/:程式安裝目錄
fox : mac系統使用者的使用者名稱

server 和 client 說明

CLIENT

CLIENT表示consul的client模式，就是客戶端模式。是consul節點的一種模式，這種模式下，所有註冊到當前節點的服務會被轉發到SERVER，本身是不持久化這些資訊。
簡單的說，client 處理健康檢查，註冊服務等，但是這個註冊只是轉發到server中，如果有成千上萬的服務，分別啟動多個client,可以減少server 壓力

SERVER

SERVER表示consul的server模式，表明這個consul是個server，這種模式下，功能和CLIENT都一樣，唯一不同的是，它會把所有的資訊持久化的本地，這樣遇到故障，資訊是可以被保留的。

SERVER-LEADER

中間那個SERVER下面有LEADER的字眼，表明這個SERVER是它們的老大，它和其它SERVER不一樣的一點是，它需要負責同步註冊的資訊給其它的SERVER，同時也要負責各個節點的健康監測。

consul 安裝

mkdir -p /Users/fox/bin/

開啟這個目錄 /Users/fox/bin/,然後下載consul
解壓縮後只有一個單檔案 consul
執行指令碼

./consul

輸出

Usage: consul [--version] [--help] <command> [<args>]

Available commands are:
    agent          Runs a Consul agent
    catalog        Interact with the catalog
    event          Fire a new event
    exec           Executes a command on Consul nodes
    force-leave    Forces a member of the cluster to enter the "left" state
    info           Provides debugging information for operators.
    join           Tell Consul agent to join cluster
    keygen         Generates a new encryption key
    keyring        Manages gossip layer encryption keys
    kv             Interact with the key-value store
    leave          Gracefully leaves the Consul cluster and shuts down
    lock           Execute a command holding a lock
    maint          Controls node or service maintenance mode
    members        Lists the members of a Consul cluster
    monitor        Stream logs from a Consul agent
    operator       Provides cluster-level tools for Consul operators
    reload         Triggers the agent to reload configuration files
    rtt            Estimates network round trip time between nodes
    snapshot       Saves, restores and inspects snapshots of Consul server state
    validate       Validate config files/directories
    version        Prints the Consul version
    watch          Watch for changes in Consul

設定環境配置

sudo vim /etc/paths.d/user_fox

內容輸入如下

/Users/fox/bin

應用生效

source /etc/profile

測試，在任何目錄中，輸入

consul

輸出

Usage: consul [--version] [--help] <command> [<args>]

Available commands are:
    agent          Runs a Consul agent
    catalog        Interact with the catalog
    event          Fire a new event
    exec           Executes a command on Consul nodes
    force-leave    Forces a member of the cluster to enter the "left" state
    info           Provides debugging information for operators.
    join           Tell Consul agent to join cluster
    keygen         Generates a new encryption key
    keyring        Manages gossip layer encryption keys
    kv             Interact with the key-value store
    leave          Gracefully leaves the Consul cluster and shuts down
    lock           Execute a command holding a lock
    maint          Controls node or service maintenance mode
    members        Lists the members of a Consul cluster
    monitor        Stream logs from a Consul agent
    operator       Provides cluster-level tools for Consul operators
    reload         Triggers the agent to reload configuration files
    rtt            Estimates network round trip time between nodes
    snapshot       Saves, restores and inspects snapshots of Consul server state
    validate       Validate config files/directories
    version        Prints the Consul version
    watch          Watch for changes in Consul

consul 引數說明

-dev 開發者模式該節點的啟動不能用於生產環境，因為該模式下不會持久化任何狀態
該啟動模式僅僅是為了快速便捷的啟動單節點consul
該節點處於server模式
該節點是leader
該節點是一個健康節點
-ui 啟動自有主機的介面
-bootstrap-expect 1 叢集節點，表示等待多少個節點再啟動，這裡是1個，一個就啟動
-bind=127.0.0.1 繫結IP ，本機IP地址，內網IP
-advertise-wan=10.23.123.12 繫結外網ip
-node=node1 節點名稱，如果沒有，預設是主機名
-server 設定為服務端
-data-dir /tmp/consul 資料儲存目錄為 /tmp/consul
-datacenter=dc1 資料中心
更多請看
https://www.consul.io/docs/agent/options.html

consul agent server client

agent可以執行在server或者client模式

consul agent server 服務端

consul agent server 服務端啟動

consul agent -dev -server -bootstrap-expect 1 -data-dir /tmp/consul -node=node1

停止

Ctrl+C  #按鍵

如果你按錯了那麼使用強制停止

ps -ef |grep consul

輸出

  501   831   813   0  1:12下午 ttys001    0:02.37 consul agent -dev -config-dir /Users/fox/bin/consul.d/
  501   890   813   0  1:16下午 ttys001    0:00.00 grep consul

第一行就是要停止的程序

kill -9 831

檢視成員

consul members

服務操作

建立一個服務

新建目錄

mkdir -p /Users/fox/bin/consul.d

建立web服務和service2服務

echo '{"service": {"name": "web", "tags": ["rails"], "port": 801}}' >/Users/fox/bin/consul.d/web.json

echo '{"service": {"name": "service2", "tags": ["rails"], "port": 802}}' >/Users/fox/bin/consul.d/service2.json

啟動代理(你要先關閉之前開啟的那個代理哦)

consul agent -dev -config-dir /Users/fox/bin/consul.d/

查詢服務

DNS 查詢

服務的DNS名稱是 NAME.service.consul
service2:服務名稱
web:服務名稱

dig @127.0.0.1 -p 8600 service2.service.consul

輸出

; <<>> DiG 9.9.7-P3 <<>> @127.0.0.1 -p 8600 service2.service.consul
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 56742
;; flags: qr aa rd; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1
;; WARNING: recursion requested but not available

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;service2.service.consul.   IN  A

;; ANSWER SECTION:
service2.service.consul. 0  IN  A   127.0.0.1

;; Query time: 0 msec
;; SERVER: 127.0.0.1#8600(127.0.0.1)
;; WHEN: Thu Jan 18 13:29:46 CST 2018
;; MSG SIZE  rcvd: 68

HTTP API 查詢

curl http://localhost:8500/v1/catalog/service/service2

輸出

[
    {
        "ID": "e3e23dc4-f3c7-24bb-e35a-53ae6bcae58a",
        "Node": "fox",
        "Address": "127.0.0.1",
        "Datacenter": "dc1",
        "TaggedAddresses": {
            "lan": "127.0.0.1",
            "wan": "127.0.0.1"
        },
        "NodeMeta": {
            "consul-network-segment": ""
        },
        "ServiceID": "service2",
        "ServiceName": "service2",
        "ServiceTags": [
            "rails"
        ],
        "ServiceAddress": "",
        "ServicePort": 802,
        "ServiceEnableTagOverride": false,
        "CreateIndex": 6,
        "ModifyIndex": 6
    }
]

查詢健康

 curl 'http://localhost:8500/v1/health/service/service2?passing'

輸出

[
    {
        "Node": {
            "ID": "e3e23dc4-f3c7-24bb-e35a-53ae6bcae58a",
            "Node": "fox",
            "Address": "127.0.0.1",
            "Datacenter": "dc1",
            "TaggedAddresses": {
                "lan": "127.0.0.1",
                "wan": "127.0.0.1"
            },
            "Meta": {
                "consul-network-segment": ""
            },
            "CreateIndex": 5,
            "ModifyIndex": 6
        },
        "Service": {
            "ID": "service2",
            "Service": "service2",
            "Tags": [
                "rails"
            ],
            "Address": "",
            "Port": 802,
            "EnableTagOverride": false,
            "CreateIndex": 6,
            "ModifyIndex": 6
        },
        "Checks": [
            {
                "Node": "fox",
                "CheckID": "serfHealth",
                "Name": "Serf Health Status",
                "Status": "passing",
                "Notes": "",
                "Output": "Agent alive and reachable",
                "ServiceID": "",
                "ServiceName": "",
                "ServiceTags": [],
                "Definition": {},
                "CreateIndex": 5,
                "ModifyIndex": 5
            }
        ]
    }
]

Consul Web介面

加入 -ui 引數，啟動自有主機的介面
啟動代理(你要先關閉之前開啟的那個代理哦)

consul agent -dev -ui -config-dir /Users/fox/bin/consul.d/

等待一會，瀏覽器中輸入如下，就可以看到UI介面了

http://localhost:8500/ui

Consul 叢集 docker版

Consul 叢集

稍後新增

A&Q

Error starting agent: Failed to start Consul server: Failed to start RPC layer: listen tcp 127.0.0.1:8300: bind: address already in use

原因：你已經啟動一個了，要麼關閉它，要麼繼續使用已經啟動過得
用這個命令檢視

ps -ef |grep consul