add_max_concurrent_in_coredns (#9307)

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

@@ -49,10 +49,12 @@ data:
 {% if upstream_dns_servers is defined and upstream_dns_servers|length > 0 %}
         forward . {{ upstream_dns_servers|join(' ') }} {
           prefer_udp
+          max_concurrent 1000
         }
 {% else %}
         forward . /etc/resolv.conf {
           prefer_udp
+          max_concurrent 1000
         }
 {% endif %}
 {% if enable_coredns_k8s_external %}