Add option to set undercloud dns nameserver

This adds an undercloud_nameserver option which will be taken into
account in os-net-config to set up the undercloud's nameserver. If left
unset, it will give an empty list to the dns_servers parameter in
os-net-config, which will actually do nothing. If set, it will use that
nameserver as the sole member of a list that is passed to the
aforementioned parameter.

Co-Authored-By: Juan Antonio Osorio Robles <jaosorior@redhat.com>
Change-Id: I2b8a3f64dc1958f00b0471b68ba8283da76a4e7b

instack_undercloud/tests/test_validator.py

@@ -121,3 +121,13 @@ class TestValidator(base.BaseTestCase):
         save_params = dict(params)
         validator.validate_config(params, lambda x: None)
         self.assertEqual(save_params, params)
+
+    def test_valid_undercloud_nameserver_passes(self):
+        self.conf.config(undercloud_nameservers=['192.168.24.4',
+                                                 '192.168.24.5'])
+        undercloud._validate_network()
+
+    def test_invalid_undercloud_nameserver_fails(self):
+        self.conf.config(undercloud_nameservers=['Iamthewalrus'])
+        self.assertRaises(validator.FailedValidation,
+                          undercloud._validate_network)

instack_undercloud/undercloud.py

@@ -135,6 +135,10 @@ _opts = [
                help=('Virtual IP address to use for the admin endpoints of '
                      'Undercloud services. Only used with SSL.')
                ),
+    cfg.ListOpt('undercloud_nameservers',
+                default=[],
+                help=('DNS nameserver(s) to use for the undercloud node.'),
+                ),
     cfg.StrOpt('undercloud_service_certificate',
                default='',
                help=('Certificate file to use for OpenStack service SSL '
@@ -928,6 +932,8 @@ def _generate_init_data(instack_env):
             open(_get_template_path('net-config.json.template')).read()
 
     context['HIERADATA_OVERRIDE'] = hiera_entry
+    context['UNDERCLOUD_NAMESERVERS'] = json.dumps(
+        CONF.undercloud_nameservers)
 
     partials = {'net_config': net_config_json}
     renderer = pystache.Renderer(partials=partials)
@@ -936,6 +942,7 @@ def _generate_init_data(instack_env):
     with open(template) as f:
         config_json = renderer.render(f.read(), context)
 
+    config_json = config_json.replace('"', '"')
     cfn_path = '/var/lib/heat-cfntools/cfn-init-data'
     tmp_json = tempfile.mkstemp()[1]
     with open(tmp_json, 'w') as f:

instack_undercloud/validator.py

@@ -34,6 +34,18 @@ def validate_config(params, error_callback):
     _validate_dhcp_range(local_params, error_callback)
     _validate_inspection_range(local_params, error_callback)
     _validate_no_overlap(local_params, error_callback)
+    _validate_ips(local_params, error_callback)
+
+
+def _validate_ips(params, error_callback):
+    def is_ip(value, param_name):
+        try:
+            netaddr.IPAddress(value)
+        except netaddr.core.AddrFormatError:
+            error_callback(
+                '%s "%s" must be a valid IP address' % (param_name, value))
+    for ip in params['undercloud_nameservers']:
+        is_ip(ip, 'undercloud_nameservers')
 
 
 def _validate_value_formats(params, error_callback):

templates/net-config.json.template

@@ -10,7 +10,8 @@
     "type": "interface",
     "name": "{{LOCAL_INTERFACE}}",
     "primary": "true",
-    "mtu": {{LOCAL_MTU}}
+    "mtu": {{LOCAL_MTU}},
+    "dns_servers": {{UNDERCLOUD_NAMESERVERS}}
    }
   ],
   "addresses": [

undercloud.conf.sample

@@ -36,6 +36,9 @@
 # services. Only used with SSL. (string value)
 #undercloud_admin_vip = 192.168.24.3
 
+# DNS nameserver(s) to use for the undercloud node. (list value)
+#undercloud_nameservers =
+
 # Certificate file to use for OpenStack service SSL connections.
 # Setting this enables SSL for the OpenStack API endpoints, leaving it
 # unset disables SSL. (string value)