I started to collect some relevant dashboards under Gerrit TCP Proxy. The dasboard combines haproxy metrics and trafficserver metrics for monitoring both ssh and https. I don't think the dashboard should be super detailed about every metric because there are more detailed dashboards in sre-traffic-team folder. Most of them allow to also filter for gerrit.discovery.wmnet.

I'll resolve this task for now, there is basic monitoring in place and existing blackbox checks should switch to the new CDN backend once the DNS entry is updated. So I'll resolve this task for now. Tweaks or new alerts might be needed, I'll reopen or open a new task then.