Add CoreDNS endpoint_pod_names option (#5012)

docs/vars.md

@@ -65,6 +65,8 @@ following default cluster parameters:
   on the CoreDNS service.
 * *coredns_k8s_external_zone* - Zone that will be used when CoreDNS k8s_external plugin is enabled
   (default is k8s_external.local)
+* *enable_coredns_k8s_endpoint_pod_names* - If enabled, it configures endpoint_pod_names option for kubernetes plugin.
+  on the CoreDNS service.
 * *cloud_provider* - Enable extra Kubelet option if operating inside GCE or
   OpenStack (default is unset)
 * *kube_hostpath_dynamic_provisioner* - Required for use of PetSets type in
@@ -102,7 +104,7 @@ Stack](https://github.com/kubernetes-sigs/kubespray/blob/master/docs/dns-stack.m
 
 * *docker_options* - Commonly used to set
   ``--insecure-registry=myregistry.mydomain:5000``
-* *docker_plugins* - This list can be used to define [Docker plugins](https://docs.docker.com/engine/extend/) to install. 
+* *docker_plugins* - This list can be used to define [Docker plugins](https://docs.docker.com/engine/extend/) to install.
 * *http_proxy/https_proxy/no_proxy* - Proxy variables for deploying behind a
   proxy. Note that no_proxy defaults to all internal cluster IPs and hostnames
   that correspond to each node.

inventory/sample/group_vars/k8s-cluster/k8s-cluster.yml

@@ -138,6 +138,8 @@ nodelocaldns_health_port: 9254
 # Enable k8s_external plugin for CoreDNS
 enable_coredns_k8s_external: false
 coredns_k8s_external_zone: k8s_external.local
+# Enable endpoint_pod_names option for kubernetes plugin
+enable_coredns_k8s_endpoint_pod_names: false
 
 # Can be docker_dns, host_resolvconf or none
 resolvconf_mode: docker_dns

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

@@ -14,6 +14,9 @@ data:
         ready
         kubernetes {{ dns_domain }} in-addr.arpa ip6.arpa {
           pods insecure
+{% if enable_coredns_k8s_endpoint_pod_names %}
+          endpoint_pod_names
+{% endif %}
 {% if resolvconf_mode == 'host_resolvconf' and upstream_dns_servers is defined and upstream_dns_servers|length > 0 %}
           upstream {{ upstream_dns_servers|join(' ') }}
 {% else %}

roles/kubespray-defaults/defaults/main.yaml

@@ -92,6 +92,8 @@ dns_servers: "{{kube_dns_servers[dns_mode]}}"
 enable_coredns_k8s_external: false
 coredns_k8s_external_zone: k8s_external.local
 
+enable_coredns_k8s_endpoint_pod_names: false
+
 # Kubernetes configuration dirs and system namespace.
 # Those are where all the additional config stuff goes
 # the kubernetes normally puts in /srv/kubernetes.