kubespray/roles/kubernetes-apps/ansible/templates/coredns-config.yml.j2

---
apiVersion: v1
kind: ConfigMap
metadata:
  name: coredns
  namespace: kube-system
  labels:
      addonmanager.kubernetes.io/mode: EnsureExists
data:
  Corefile: |
    .:53 {
        errors
        health
        ready
        kubernetes {{ dns_domain }} in-addr.arpa ip6.arpa {
          pods insecure
{% if resolvconf_mode == 'host_resolvconf' and upstream_dns_servers is defined and upstream_dns_servers|length > 0 %}
          upstream {{ upstream_dns_servers|join(' ') }}
{% else %}
          upstream /etc/resolv.conf
{% endif %}
          fallthrough in-addr.arpa ip6.arpa
        }
        prometheus :9153
{% if resolvconf_mode == 'host_resolvconf' and upstream_dns_servers is defined and upstream_dns_servers|length > 0 %}
        forward . {{ upstream_dns_servers|join(' ') }} {
          prefer_udp
        }
{% else %}
        forward . /etc/resolv.conf {
          prefer_udp
        }
{% endif %}
{% if enable_coredns_k8s_external %}
        k8s_external {{ coredns_k8s_external_zone }}
{% endif %}
        cache 30
        loop
        reload
        loadbalance
    }