<div><div><div dir="auto">I have only limited experience with Prometheus, but I believe this just means that the service is responding on its metrics endpoint, not saying anything about what those metrics may be saying.</div></div><div><div dir="auto"><br></div><div dir="auto">The way I understand it, Prometheus has a list of \u201ctargets\u201d which it will \u201cscrape\u201d in a mostly round-robin manner. The targets can be listed individually in config, or be discovered by a service-discovery mechanism.</div><div dir="auto"><br></div><div dir="auto">In your case, I think the Targets are the black box-exporter services. They are responding, so are considered up, even though the SSH service they are monitoring is down (probe_status=0)</div><div dir="auto"><br></div><div dir="auto">Service discovery is pretty neat IMO. For example, Prometheus can access a Docker daemon, then add a new Target for each container (potentially filtering by container metadata like labels). So you can label all your containers/Swarm Services that expose Prom. metrics, and they will automagically show up as scrape targets and start reporting results.</div><div dir="auto"><br></div><div dir="auto">On Sun, May 17, 2026 at 2:41\u202fPM Khalid Baheyeldin <<a href="mailto:kb@2bits.com" target="_blank">kb@2bits.com</a>> wrote:<br></div></div></div><div><div><div dir="auto"><div class="gmail_quote" dir="auto"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div style="font-size:small" class="gmail_default">Thanks to everyone who chimed in about Prometheus.</div><div style="font-size:small" class="gmail_default"><br></div><div style="font-size:small" class="gmail_default">I was able to get it up and running on the same VPS as Nagios4.</div><div style="font-size:small" class="gmail_default"><br></div><div style="font-size:small" class="gmail_default">And was able to configure it to send emails when something is down and also when it is up again.</div><div style="font-size:small" class="gmail_default">This was mainly done with the prometheus-blackbox-exporter and prometheus-alertmanager packages, and checking SSH, HTTP and Drupal.</div><div style="font-size:small" class="gmail_default"><br></div><div style="font-size:small" class="gmail_default">For SSH, I use the 'ssh_banner' module, with:</div><div style="font-size:small" class="gmail_default">({__name__="probe_success",job="SSH"} == 0)</div><div style="font-size:small" class="gmail_default"><br></div><div style="font-size:small" class="gmail_default">For HTTP, I use the 'http_2xx' module, with:</div>({__name__="probe_http_status_code",job="<span class="gmail_default" style="font-size:small">HTTPServers</span>"} != 200)</div><div dir="ltr"><br><div style="font-size:small" class="gmail_default">I think I covered everything that my Nagios4 instance currently does, and would be decommissioning it soon.</div><div style="font-size:small" class="gmail_default"><br></div><div style="font-size:small" class="gmail_default">But there is a snag, or misunderstanding on my part:</div><div style="font-size:small" class="gmail_default">When an alert fires, I do get an email about the failure.</div><div style="font-size:small" class="gmail_default">But, when I go to Status -> Targets, the hosts that failed still show as UP.</div><div style="font-size:small" class="gmail_default"><br></div><div style="font-size:small" class="gmail_default">Probably because there is still a response from them?</div><div style="font-size:small" class="gmail_default"><br></div><div style="font-size:small" class="gmail_default">Can one comment on this?</div></div></div>
</div>
</div>
</div>
_______________________________________________<br>
kwlug-disc mailing list<br>
To unsubscribe, send an email to <a href="mailto:kwlug-disc-leave@kwlug.org" target="_blank">kwlug-disc-leave@kwlug.org</a><br>
with the subject "unsubscribe", or email<br>
<a href="mailto:kwlug-disc-owner@kwlug.org" target="_blank">kwlug-disc-owner@kwlug.org</a> to contact a human being.<br>
</blockquote></div></div>
</div>
</div>