服務註冊方式

Consul註冊服務的方式有兩種：
1.配置文件
2.API接口redis

固然做爲微服務的註冊中心，添加配置文件後，能夠reload配置，不須要停機。 json

查詢服務

查詢已經註冊的服務有三種方式:數組

1. API查詢
2. 命令行查詢
3. DNS查詢

例子

下面經過例子，演示相關操做。curl

定義服務

咱們經過配置文件註冊一個服務。
按照約定，把配置文件放在/etc/consul.d中。ide

root@598361668db6:/data# mkdir /etc/consul.d
root@598361668db6:/etc/consul.d# echo '{"service":{"name":"student","tags":["student"],"port":80}}'>/etc/consul.d/student.json
root@598361668db6:/data# nohup ./consul agent -dev -client 0.0.0.0 -config-dir=/etc/consul.d >consul.log &

咱們看到配置文件是JSON格式的。而且咱們定義了名爲student的服務，同時給服務添加了一個標籤也叫student，端口爲80。
爲了方便快速閱讀，JSON文件完整的格式參照文章結尾處。微服務

查詢服務

界面查看

API查詢

root@598361668db6:/data# curl http://localhost:8500/v1/catalog/service/student
[
    {
        "ID": "eece8f25-51f9-a62d-ca02-7dacf641716e",
        "Node": "598361668db6",
        "Address": "127.0.0.1",
        "Datacenter": "dc1",
        "TaggedAddresses": {
            "lan": "127.0.0.1",
            "wan": "127.0.0.1"
        },
        "NodeMeta": {
            "consul-network-segment": ""
        },
        "ServiceID": "student",
        "ServiceName": "student",
        "ServiceTags": [
            "student"
        ],
        "ServiceAddress": "",
        "ServicePort": 80,
        "ServiceEnableTagOverride": false,
        "CreateIndex": 6,
        "ModifyIndex": 6
    }
]

API查詢可用服務

root@598361668db6:/data# curl 'http://localhost:8500/v1/health/service/student?passing'
[
    {
        "Node": {
            "ID": "eece8f25-51f9-a62d-ca02-7dacf641716e",
            "Node": "598361668db6",
            "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": "student",
            "Service": "student",
            "Tags": [
                "student"
            ],
            "Address": "",
            "Port": 80,
            "EnableTagOverride": false,
            "CreateIndex": 6,
            "ModifyIndex": 6
        },
        "Checks": [
            {
                "Node": "598361668db6",
                "CheckID": "serfHealth",
                "Name": "Serf Health Status",
                "Status": "passing",
                "Notes": "",
                "Output": "Agent alive and reachable",
                "ServiceID": "",
                "ServiceName": "",
                "ServiceTags": [],
                "Definition": {},
                "CreateIndex": 5,
                "ModifyIndex": 5
            }
        ]
    }
]

DNS查詢

consul會在DNS中爲每一個服務添加一條A記錄，名稱爲serviceName.service.consul。若是服務有標籤還會添加一個tag.serviceName.service.consul的記錄。url

root@598361668db6:/data# dig @127.0.0.1 -p 8600 student.service.consul

; <<>> DiG 9.10.3-P4-Ubuntu <<>> @127.0.0.1 -p 8600 student.service.consul
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 52319
;; 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:
;student.service.consul.        IN  A

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

;; Query time: 2 msec
;; SERVER: 127.0.0.1#8600(127.0.0.1)
;; WHEN: Wed Dec 20 12:15:42 UTC 2017
;; MSG SIZE  rcvd: 67

root@598361668db6:/data# dig @127.0.0.1 -p 8600 student.student.service.consul

; <<>> DiG 9.10.3-P4-Ubuntu <<>> @127.0.0.1 -p 8600 student.student.service.consul
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 32043
;; 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:
;student.student.service.consul.    IN  A

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

;; Query time: 0 msec
;; SERVER: 127.0.0.1#8600(127.0.0.1)
;; WHEN: Wed Dec 20 12:15:52 UTC 2017
;; MSG SIZE  rcvd: 75

不用停機動態更新服務

root@598361668db6:/data# ./consul reload
Configuration reload triggered

附錄

JSON文件完整格式

{
  "service": {
        "id": "red0",
    "name": "redis",
    "tags": ["primary"],
    "address": "",
    "port": 8000,
    "enable_tag_override": false,
    "checks": [
      {
        "script": "/usr/local/bin/check_redis.py",
        "interval": "10s"
      }
    ]
  }
}

含義：命令行

關於ckecks會在下文中具體介紹。code