core-deployments/cert-manager/issuer.yaml

---
apiVersion: cert-manager.io/v1
kind: ClusterIssuer
metadata:
  name: letsencrypt-prod
spec:
  acme:
    email: letsencrypt@ar21.de
    server: https://acme-v02.api.letsencrypt.org/directory
    privateKeySecretRef:
      name: letsencrypt-prod-key
    solvers:
      - http01:
        ingress:
          class: traefik
---
apiVersion: cert-manager.io/v1
kind: ClusterIssuer
metadata:
  name: letsencrypt-staging
spec:
  acme:
    email: letsencrypt@ar21.de
    server: https://acme-staging-v02.api.letsencrypt.org/directory
    privateKeySecretRef:
      name: letsencrypt-staging-key
    solvers:
      - http01:
        ingress:
          class: traefik