https://blog.devops.dev/prometheus-blackbox-exporter-with-kube-prometheus-stack-23a045ccbab2
curl http://blackbox-exporter-prometheus-blackbox-exporter.prometheus:9115/probe?target=example.com:443&module=tcp_connect&debug=true
https://blog.ruanbekker.com/cheatsheets/blackbox-exporter/
https://superuser.com/questions/1680156/prometheus-blackbox-exporter-tcp-probe-returns-value-of-0-even-when-port-is-ope
https://dmachard.github.io/posts/0043-blackbox-prometheus-dns/