Make /etc/default/libvirt-bin systemd compatible

When running under systemd libvirtd should not use the daemon mode flag '-d'
as systemd looses track of the process and marks it as dead.

Change-Id: I5f22e00338373e4d2218f1bbdb906e6a24c332e2
Closes-Bug: 1567180

hooks/nova_compute_context.py

@@ -4,7 +4,11 @@ import platform
 
 from charmhelpers.core.unitdata import kv
 from charmhelpers.contrib.openstack import context
-from charmhelpers.core.host import service_running, service_start
+from charmhelpers.core.host import (
+    lsb_release,
+    service_running,
+    service_start,
+)
 from charmhelpers.fetch import apt_install, filter_installed_packages
 from charmhelpers.core.hookenv import (
     config,
@@ -100,12 +104,13 @@ class NovaComputeLibvirtContext(context.OSContextGenerator):
     def __call__(self):
         # distro defaults
         ctxt = {
-            # /etc/default/libvirt-bin
-            'libvirtd_opts': '-d',
             # /etc/libvirt/libvirtd.conf (
-            'listen_tls': 0,
+            'listen_tls': 0
         }
-
+        if lsb_release()['DISTRIB_CODENAME'].lower() < "wily":
+            ctxt['libvirtd_opts'] = '-d'
+        else:
+            ctxt['libvirtd_opts'] = ''
         # get the processor architecture to use in the nova.conf template
         ctxt['arch'] = platform.machine()
 

unit_tests/test_nova_compute_contexts.py

@@ -16,6 +16,7 @@ TO_PATCH = [
     'log',
     '_save_flag_file',
     'unit_get',
+    'lsb_release',
 ]
 
 NEUTRON_CONTEXT = {
@@ -217,6 +218,18 @@ class NovaComputeContextTests(CharmTestCase):
         self.assertEqual(libvirt()['host_uuid'],
                          '73874c1c-ba48-406d-8d99-ac185d83b9bc')
 
+    def test_libvirt_opts_trusty(self):
+        self.kv.return_value = FakeUnitdata(**{'host_uuid': self.host_uuid})
+        self.lsb_release.return_value = {'DISTRIB_CODENAME': 'trusty'}
+        libvirt = context.NovaComputeLibvirtContext()
+        self.assertEqual(libvirt()['libvirtd_opts'], '-d')
+
+    def test_libvirt_opts_xenial(self):
+        self.kv.return_value = FakeUnitdata(**{'host_uuid': self.host_uuid})
+        self.lsb_release.return_value = {'DISTRIB_CODENAME': 'xenial'}
+        libvirt = context.NovaComputeLibvirtContext()
+        self.assertEqual(libvirt()['libvirtd_opts'], '')
+
     @patch.object(context.NeutronComputeContext, 'network_manager')
     @patch.object(context.NeutronComputeContext, 'plugin')
     def test_disable_security_groups_true(self, plugin, nm):