Add dns role

This patch adds the dns role created from validations/dns.yaml.

Change-Id: I6f64bad2f834b372e693f70cf12beaa1288c549c
Implements: blueprint validation-framework
Signed-off-by: Gael Chamoulaud <gchamoul@redhat.com>

playbooks/dns.yaml

@@ -0,0 +1,12 @@
+---
+- hosts: undercloud, overcloud
+  vars:
+    metadata:
+      name: Verify DNS
+      description: >
+        Verify that the DNS resolution works
+      groups:
+        - pre-deployment
+    server_to_lookup: example.com
+  roles:
+    - dns

roles/dns/defaults/main.yml

@@ -0,0 +1,2 @@
+---
+server_to_lookup: example.com

roles/dns/meta/main.yml

@@ -0,0 +1,28 @@
+galaxy_info:
+  author: TripleO Validations Team
+  company: Red Hat
+  license: Apache
+  min_ansible_version: 2.4
+
+  platforms:
+  - name: CentOS
+    versions:
+    - 7
+  - name: RHEL
+    versions:
+    - 7
+
+  categories:
+    - cloud
+    - baremetal
+    - system
+
+  galaxy_tags: []
+    # List tags for your role here, one per line. A tag is a keyword that describes
+    # and categorizes the role. Users find roles by searching for tags. Be sure to
+    # remove the '[]' above, if you add tags to this list.
+    #
+    # NOTE: A tag is limited to a single word comprised of alphanumeric characters.
+    #       Maximum 20 tags per role.
+
+dependencies: []

roles/dns/tasks/main.yml

@@ -0,0 +1,4 @@
+---
+- name: Ensure DNS resolution works
+  command: "getent hosts {{ server_to_lookup }}"
+  changed_when: False

roles/dns/vars/main.yml

@@ -0,0 +1,7 @@
+---
+metadata:
+  name: Verify DNS
+  description: >
+    Verify that the DNS resolution works
+  groups:
+    - pre-deployment