From bd6d810d0a963055c56ad0275b4ba778d92b124b Mon Sep 17 00:00:00 2001
From: Cristian Calin <6627509+cristicalin@users.noreply.github.com>
Date: Tue, 29 Jun 2021 15:28:41 +0300
Subject: [PATCH] nodelocaldns: allow binding metrics address to host IP
 (#7748)

---
 .../sample/group_vars/k8s_cluster/k8s-cluster.yml      |  1 +
 .../ansible/templates/nodelocaldns-config.yml.j2       | 10 +++++-----
 .../ansible/templates/nodelocaldns-daemonset.yml.j2    |  7 +++++++
 roles/kubespray-defaults/defaults/main.yaml            |  1 +
 4 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/inventory/sample/group_vars/k8s_cluster/k8s-cluster.yml b/inventory/sample/group_vars/k8s_cluster/k8s-cluster.yml
index c369324ff..45a9a0a1c 100644
--- a/inventory/sample/group_vars/k8s_cluster/k8s-cluster.yml
+++ b/inventory/sample/group_vars/k8s_cluster/k8s-cluster.yml
@@ -166,6 +166,7 @@ dns_mode: coredns
 enable_nodelocaldns: true
 nodelocaldns_ip: 169.254.25.10
 nodelocaldns_health_port: 9254
+nodelocaldns_bind_metrics_host_ip: false
 # nodelocaldns_external_zones:
 # - zones:
 #   - example.com
diff --git a/roles/kubernetes-apps/ansible/templates/nodelocaldns-config.yml.j2 b/roles/kubernetes-apps/ansible/templates/nodelocaldns-config.yml.j2
index 6e6adf012..18abf8ea3 100644
--- a/roles/kubernetes-apps/ansible/templates/nodelocaldns-config.yml.j2
+++ b/roles/kubernetes-apps/ansible/templates/nodelocaldns-config.yml.j2
@@ -17,7 +17,7 @@ data:
         loop
         bind {{ nodelocaldns_ip }}
         forward . {{ block['nameservers'] | join(' ') }}
-        prometheus :9253
+        prometheus {% if nodelocaldns_bind_metrics_host_ip %}{$MY_HOST_IP}{% endif %}:9253
         log
 {% if dns_etchosts | default(None) %}
         hosts /etc/coredns/hosts {
@@ -39,7 +39,7 @@ data:
         forward . {{ forwardTarget }} {
             force_tcp
         }
-        prometheus :9253
+        prometheus {% if nodelocaldns_bind_metrics_host_ip %}{$MY_HOST_IP}{% endif %}:9253
         health {{ nodelocaldns_ip }}:{{ nodelocaldns_health_port }}
 {% if dns_etchosts | default(None) %}
         hosts /etc/coredns/hosts {
@@ -56,7 +56,7 @@ data:
         forward . {{ forwardTarget }} {
             force_tcp
         }
-        prometheus :9253
+        prometheus {% if nodelocaldns_bind_metrics_host_ip %}{$MY_HOST_IP}{% endif %}:9253
     }
     ip6.arpa:53 {
         errors
@@ -67,7 +67,7 @@ data:
         forward . {{ forwardTarget }} {
             force_tcp
         }
-        prometheus :9253
+        prometheus {% if nodelocaldns_bind_metrics_host_ip %}{$MY_HOST_IP}{% endif %}:9253
     }
     .:53 {
         errors
@@ -76,7 +76,7 @@ data:
         loop
         bind {{ nodelocaldns_ip }}
         forward . {{ upstreamForwardTarget }}
-        prometheus :9253
+        prometheus {% if nodelocaldns_bind_metrics_host_ip %}{$MY_HOST_IP}{% endif %}:9253
 {% if dns_etchosts | default(None) %}
         hosts /etc/coredns/hosts {
           fallthrough
diff --git a/roles/kubernetes-apps/ansible/templates/nodelocaldns-daemonset.yml.j2 b/roles/kubernetes-apps/ansible/templates/nodelocaldns-daemonset.yml.j2
index 4d725577e..7abd28ffa 100644
--- a/roles/kubernetes-apps/ansible/templates/nodelocaldns-daemonset.yml.j2
+++ b/roles/kubernetes-apps/ansible/templates/nodelocaldns-daemonset.yml.j2
@@ -41,6 +41,13 @@ spec:
         args: [ "-localip", "{{ nodelocaldns_ip }}", "-conf", "/etc/coredns/Corefile", "-upstreamsvc", "coredns" ]
         securityContext:
           privileged: true
+{% if nodelocaldns_bind_metrics_host_ip %}
+        env:
+          - name: MY_HOST_IP
+            valueFrom:
+              fieldRef:
+                fieldPath: status.hostIP
+{% endif %}
         ports:
         - containerPort: 53
           name: dns
diff --git a/roles/kubespray-defaults/defaults/main.yaml b/roles/kubespray-defaults/defaults/main.yaml
index b3c976067..3238fcbd2 100644
--- a/roles/kubespray-defaults/defaults/main.yaml
+++ b/roles/kubespray-defaults/defaults/main.yaml
@@ -89,6 +89,7 @@ dns_mode: coredns
 enable_nodelocaldns: true
 nodelocaldns_ip: 169.254.25.10
 nodelocaldns_health_port: 9254
+nodelocaldns_bind_metrics_host_ip: false
 
 # Should be set to a cluster IP if using a custom cluster DNS
 manual_dns_server: ""