I continue to learn “tricks” with Prometheus and (kube-prometheus ⊃ Prometheus Operator).

For too long, I’ve lived with Alertmanager alerts including “View in Alertmanager” and “Source” hyperlinks that don’t work because they defaulted incorrectly.

The solution when running either Prometheus or Alertmanager (same for both) is to use the flag:

--web.external-url="${EXTERNAL_URL}"

Conveniently, when running kube-prometheus, there are Prometheus and Alertmanager CRDs for configuring Prometheus and Alertmanager and these include the field:

externalUrl: "${EXTERNAL_URL}"

The question is: How to configure this value?

Using MicroK8s with the new observability addon which uses Helm to install kube-prometheus.

This results in various Resources including several Service’s:

kubectl get services \
--namespace=observability

NAME                                      TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)
alertmanager-operated                     ClusterIP   None             <none>        9093/TCP,9094/TCP,9094/UDP
kube-prom-stack-kube-prome-alertmanager   ClusterIP   10.152.183.201   <none>        9093/TCP
kube-prom-stack-kube-prome-operator       ClusterIP   10.152.183.44    <none>        443/TCP
kube-prom-stack-kube-prome-prometheus     ClusterIP   10.152.183.206   <none>        9090/TCP
kube-prom-stack-kube-state-metrics        ClusterIP   10.152.183.126   <none>        8080/TCP
prometheus-operated                       ClusterIP   None             <none>        9090/TCP

I’m using Tailscale Kubernetes Operator to expose MicroK8s services using Ingress to my tailnet.