Prometheus Blackbox - Making HTTP request to HTTPS URL which is causing problems

Question

I am trying to setup blackbox exporter with my web server but I keep getting an error. I believe the error is being caused by blackbox making a HTTP request to a HTTPS URL.

I have removed the IP address and domain name from the log for security. My website has an SSL certificate assigned to it via DigiCert.

Here is the log: Logs for the probe: level=info msg="Making HTTP request" url=https://00.00.40.248 host=DOMAINNAME level=error msg="Error for HTTP request" err="Get "https://00.00.40.248": tls: failed to verify certificate: x509: certificate signed by unknown authority"

I've tried numerous changes to my prometheus and blackbox config file but the configuration I currently have is the best results I've gotten. I can see the domain name in the prometheus UI with the target using HTTPS.

Prometheus.yml

scrape_configs:
  - job_name: 'webserver'
    metrics_path: /probe
    params:
      module: [http_2xx]
    static_configs:
      - targets:
        - https://DOMAINNAME  
    relabel_configs:
      - source_labels: [__address__]
        target_label: __param_target
      - source_labels: [__param_target]
        target_label: instance
      - target_label: __address__
        replacement: 192.00.00.18:9115  

  - job_name: 'prometheus'
    static_configs:
      - targets:
        - localhost:9090  # Replace with the address where Prometheus is running

Blackbox.yml

modules:
  http_2xx:
    prober: http
    timeout: 5s
    http:
      valid_http_versions: ["HTTP/1.1", "HTTP/2.0"]
      valid_status_codes: []
      method: GET
      preferred_ip_protocol: "ip4"
      ip_protocol_fallback: false
  icmp:
    prober: icmp
    icmp:
      preferred_ip_protocol: "ip4"
      ip_protocol_fallback: false

Answer 1

To resolve the problem, I updated my blackbox.yml file to the below.

modules:
  http_2xx:
    prober: http
    timeout: 5s
    http:
      valid_http_versions: ["HTTP/1.1", "HTTP/2.0"]
      valid_status_codes: []
      method: GET
      preferred_ip_protocol: "ip4"
      ip_protocol_fallback: false 
      tls_config:
        insecure_skip_verify: false
        ca_file: /home/pi/woodlandgrants.uk.crt
  icmp:
    prober: icmp
    timeout: 5s
    icmp:
      preferred_ip_protocol: "ip4"
      ip_protocol_fallback: false