blackbox exporter

https://github.com/prometheus/blackbox_exporter

https://github.com/prometheus/blackbox_exporter/blob/master/CONFIGURATION.md

2. relabelling的理解

Before applying the relabeling rules, the URI of a request Prometheus would make would look like this:
 "http://prometheus.io/probe?module=http_2xx". After relabeling it will look like this "http://localhost:9115/probe?target=http://prometheus.io&module=http_2xx".

First we take the values from the label __address__ (which contain the values from targets)
 and write them to a new label __param_target which will add a parameter target to the Prometheus scrape requests:

relabel_configs:
    - source_labels: [__address__]
      target_label: __param_target

参考： https://prometheus.io/docs/guides/multi-target-exporter/#querying-multi-target-exporters-with-prometheus

3.自定义HTTP请求

如果HTTP服务启用了安全认证，Blockbox Exporter内置了对basic_auth的支持，可以直接设置相关的认证信息即可：

http_basic_auth_example:
    prober: http
    timeout: 5s
    http:
      method: POST
      headers:
        Host: "login.example.com"
      basic_auth:
        username: "username"
        password: "mysecret"

https://yunlzheng.gitbook.io/prometheus-book/part-ii-prometheus-jin-jie/exporter/commonly-eporter-usage/install_blackbox_exporter#zi-ding-yi-http-qing-qiu

用一个例子来演示会更加清晰