Add support for dns_etchosts (#6236)

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

@@ -17,6 +17,11 @@ data:
         loadbalance
         cache {{ block['cache'] | default(5) }}
         reload
+{% if dns_etchosts | default(None) %}
+        hosts /etc/coredns/hosts {
+          fallthrough
+        }
+{% endif %}
     }
 {%   endfor %}
 {% endif %}
@@ -50,4 +55,13 @@ data:
         loop
         reload
         loadbalance
+{% if dns_etchosts | default(None) %}
+        hosts /etc/coredns/hosts {
+          fallthrough
+        }
+{% endif %}
     }
+{% if dns_etchosts | default(None) %}
+  hosts: |
+   {{ dns_etchosts }}
+{% endif %}

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

@@ -110,3 +110,7 @@ spec:
             items:
             - key: Corefile
               path: Corefile
+{% if dns_etchosts | default(None) %}
+            - key: hosts
+              path: hosts
+{% endif %}

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

@@ -19,6 +19,11 @@ data:
         forward . {{ block['nameservers'] | join(' ') }}
         prometheus :9253
         log
+{% if dns_etchosts | default(None) %}
+        hosts /etc/coredns/hosts {
+          fallthrough
+        }
+{% endif %}
     }
 {% endfor %}
 {% endif %}
@@ -36,6 +41,11 @@ data:
         }
         prometheus :9253
         health {{ nodelocaldns_ip }}:{{ nodelocaldns_health_port }}
+{% if dns_etchosts | default(None) %}
+        hosts /etc/coredns/hosts {
+          fallthrough
+        }
+{% endif %}
     }
     in-addr.arpa:53 {
         errors
@@ -67,4 +77,13 @@ data:
         bind {{ nodelocaldns_ip }}
         forward . {{ upstreamForwardTarget }}
         prometheus :9253
+{% if dns_etchosts | default(None) %}
+        hosts /etc/coredns/hosts {
+          fallthrough
+        }
+{% endif %}
     }
+{% if dns_etchosts | default(None) %}
+  hosts: |
+   {{ dns_etchosts }}
+{% endif %}

roles/kubernetes-apps/ansible/templates/nodelocaldns-daemonset.yml.j2

@@ -79,6 +79,10 @@ spec:
             items:
             - key: Corefile
               path: Corefile
+{% if dns_etchosts | default(None) %}
+            - key: hosts
+              path: hosts
+{% endif %}
         - name: xtables-lock
           hostPath:
             path: /run/xtables.lock