Provide fallback config options for HA VIP iface and cidr when it cannot be automatically determined

config.yaml

@@ -130,6 +130,18 @@ options:
       .
       If multiple networks are being used, a VIP should be provided for each
       network, separated by spaces.
+  vip_iface:
+    type: string
+    default: eth0
+    description: |
+      Default network interface to use for HA vip when it cannot be automatically
+      determined.
+  vip_cidr:
+    type: int
+    default: 24
+    description: |
+      Default CIDR netmask to use for HA vip when it cannot be automatically
+      determined.
   ha-bindiface:
     type: string
     default: eth0

hooks/keystone_hooks.py

@@ -270,7 +270,11 @@ def ha_joined():
             res_ks_vip = 'ocf:heartbeat:IPaddr2'
             vip_params = 'ip'
 
-        iface = get_iface_for_address(vip)
+        iface = (get_iface_for_address(vip) or
+                 config('vip_iface'))
+        netmask = (get_netmask_for_address(vip) or
+                   config('vip_cidr'))
+
         if iface is not None:
             vip_key = 'res_ks_{}_vip'.format(iface)
             resources[vip_key] = res_ks_vip
@@ -279,7 +283,7 @@ def ha_joined():
                 ' nic="{iface}"'.format(ip=vip_params,
                                         vip=vip,
                                         iface=iface,
-                                        netmask=get_netmask_for_address(vip))
+                                        netmask=netmask)
             )
             vip_group.append(vip_key)
 

unit_tests/test_keystone_hooks.py

@@ -381,6 +381,31 @@ class KeystoneRelationTests(CharmTestCase):
         }
         self.relation_set.assert_called_with(**args)
 
+    def test_ha_joined_no_bound_ip(self):
+        self.get_hacluster_config.return_value = {
+            'vip': '10.10.10.10',
+            'ha-bindiface': 'em0',
+            'ha-mcastport': '8080'
+        }
+        self.test_config.set('vip_iface', 'eth120')
+        self.test_config.set('vip_cidr', '21')
+        self.get_iface_for_address.return_value = None
+        self.get_netmask_for_address.return_value = None
+        hooks.ha_joined()
+        args = {
+            'corosync_bindiface': 'em0',
+            'corosync_mcastport': '8080',
+            'init_services': {'res_ks_haproxy': 'haproxy'},
+            'resources': {'res_ks_eth120_vip': 'ocf:heartbeat:IPaddr2',
+                          'res_ks_haproxy': 'lsb:haproxy'},
+            'resource_params': {
+                'res_ks_eth120_vip': 'params ip="10.10.10.10"'
+                                     ' cidr_netmask="21" nic="eth120"',
+                'res_ks_haproxy': 'op monitor interval="5s"'},
+            'clones': {'cl_ks_haproxy': 'res_ks_haproxy'}
+        }
+        self.relation_set.assert_called_with(**args)
+
     def test_ha_joined_with_ipv6(self):
         self.test_config.set('prefer-ipv6', True)
         self.get_hacluster_config.return_value = {