本节重点介绍 :

• http型的服务发现的优点
• 使用go语言编写 http服务发现源
• 将blackbox-http job改造为 http服务发现类型

说明

对比file_sd的优点

• 不再依赖文件做传输。不需要confd或者ansible copy file的机制
• 直接在服务发现源(CMDB)启动一个接口
• 返回 json的target数据

[
  {
    "targets": [ "<host>", ... ],
    "labels": {
      "<labelname>": "<labelvalue>", ...
    }
  },
  ...
]

文档地址

• http_sd_configs配置文档

编写go的http发现源

使用gin启动web

package main

import (
	"flag"
	"github.com/gin-gonic/gin"
	"math/rand"
)


func main() {

	listenAddress := flag.String("addr", ":8001",
		"Address on which to expose metrics and web interface.")
	flag.Parse()
	r := gin.Default()

	r.GET("/prome_http_sd", httpSd)
	r.Run(*listenAddress) // listen and serve on 0.0.0.0:8080 (for windows "localhost:8080")
}

编写target数据结构

type target struct {
	Targets []string          `json:"targets"`
	Labels  map[string]string `json:"labels"`
}

编写 httpSd 处理函数

• frn返回一个最大值为n的随机整数
• randMapKeys 作为随机标签的key
• randMapValues 作为随机标签的value
• 遍历nodes切片mock target数据
• 返回targets json数据

func httpSd(c *gin.Context) {

	nodes := []string{
		"172.20.70.205:9115",
		"http://prometheus.io",
		"http://www.baidu.com",
		"https://www.baidu.com",
		"https://github.com/",
	}
	randMapKeys := []string{"arch", "idc", "os", "job"}
	randMapValues := []string{"linux", "beijing", "centos", "arm64"}
	frn := func(n int) int {
		return rand.Intn(n)
	}

	targets := make([]target, 0)
	for _, n := range nodes {
		num := len(randMapKeys)
		m := make(map[string]string, num)
		for i := 0; i < num; i++ {
			m[randMapKeys[frn(len(randMapKeys)-1)]] = randMapValues[frn(len(randMapValues)-1)]
		}
		t := target{
			Targets: []string{n},
			Labels:  m,
		}
		targets = append(targets, t)
	}

	c.JSON(200, targets)
}

完整go代码

package main

import (
	"flag"
	"github.com/gin-gonic/gin"
	"math/rand"
)


func main() {

	listenAddress := flag.String("addr", ":8001",
		"Address on which to expose metrics and web interface.")
	flag.Parse()
	r := gin.Default()

	r.GET("/prome_http_sd", httpSd)
	r.Run(*listenAddress) // listen and serve on 0.0.0.0:8080 (for windows "localhost:8080")
}

type target struct {
	Targets []string          `json:"targets"`
	Labels  map[string]string `json:"labels"`
}

func httpSd(c *gin.Context) {

	nodes := []string{
		"172.20.70.205:9115",
		"http://prometheus.io",
		"http://www.baidu.com",
		"https://www.baidu.com",
		"https://github.com/",
	}
	randMapKeys := []string{"arch", "idc", "os", "job"}
	randMapValues := []string{"linux", "beijing", "centos", "arm64"}
	frn := func(n int) int {
		return rand.Intn(n)
	}

	targets := make([]target, 0)
	for _, n := range nodes {
		num := len(randMapKeys)
		m := make(map[string]string, num)
		for i := 0; i < num; i++ {
			m[randMapKeys[frn(len(randMapKeys)-1)]] = randMapValues[frn(len(randMapValues)-1)]
		}
		t := target{
			Targets: []string{n},
			Labels:  m,
		}
		targets = append(targets, t)
	}

	c.JSON(200, targets)
}

请求接口看返回

[root@k8s-master01 ~]#  curl -s http://localhost:8001/prome_http_sd |python -m json.tool
[
    {
        "labels": {
            "arch": "linux",
            "idc": "centos",
            "os": "centos"
        },
        "targets": [
            "172.20.70.205:9115"
        ]
    },
    {
        "labels": {
            "arch": "beijing",
            "os": "beijing"
        },
        "targets": [
            "http://prometheus.io"
        ]
    },
    {
        "labels": {
            "arch": "centos",
            "os": "centos"
        },
        "targets": [
            "http://www.baidu.com"
        ]
    },
    {
        "labels": {
            "arch": "beijing",
            "idc": "beijing",
            "os": "linux"
        },
        "targets": [
            "https://www.baidu.com"
        ]
    },
    {
        "labels": {
            "arch": "beijing",
            "idc": "linux"
        },
        "targets": [
            "https://github.com/"
        ]
    }
]

将blackbox-http job改造为 http服务发现类型

修改prometheus配置文件

• 传入http_sd_configs 的url
• 其余relabel配置不变

  - job_name: 'blackbox-http-sd'
    metrics_path: /probe
    # 传入的参数
    params:
      module: [http_2xx]  # Look for a HTTP 200 response.
    scrape_interval: 15s
    scrape_timeout: 10s
    scheme: http
    honor_timestamps: false
    http_sd_configs:
    - url: http://172.20.70.205:8001/prome_http_sd 
    relabel_configs:
      - source_labels: [__address__]
        target_label: __param_target
      - source_labels: [__param_target]
        target_label: instance
      - target_label: __address__
        replacement: 172.20.70.205:9115 

页面观察结果

• target页面
• 
• discovery页面
• 
• http发现源侧看到的prometheus请求
• 

本节重点总结 :

• http型的服务发现的优点
• 使用go语言编写 http服务发现源
• 将blackbox-http job改造为 http服务发现类型