Add support for lxc consoles.

Add lxc console support. Similar to how we get console
on libvirt-xen domains. This fixes bug 853602.

Change-Id: Ib39953b804dc3284132651f29f33ad5783d1959a
Signed-off-by: Chuck Short <chuck.short@canonical.com>

nova/virt/libvirt.xml.template

@@ -6,6 +6,7 @@
 #if $type == 'lxc'
         <type>exe</type>
         <init>/sbin/init</init>
+        <cmdline>console=ttyS0</cmdline>
 #else if $type == 'uml'
     #set $root_disk_bus = 'uml'
     #set $ephemeral_disk_bus = 'uml'

nova/virt/libvirt/connection.py

@@ -880,7 +880,7 @@ def _wait_for_boot():
         timer = utils.LoopingCall(_wait_for_boot)
         return timer.start(interval=0.5, now=True)
 
-    def _flush_xen_console(self, virsh_output):
+    def _flush_libvirt_console(self, virsh_output):
         LOG.info(_('virsh said: %r'), virsh_output)
         virsh_output = virsh_output[0].strip()
 
@@ -919,11 +919,17 @@ def get_console_output(self, instance):
             virsh_output = utils.execute('virsh',
                                          'ttyconsole',
                                          instance['name'])
-            data = self._flush_xen_console(virsh_output)
+            data = self._flush_libvirt_console(virsh_output)
             fpath = self._append_to_file(data, console_log)
         elif FLAGS.libvirt_type == 'lxc':
             # LXC is also special
-            LOG.info(_("Unable to read LXC console"), instance=instance)
+            virsh_output = utils.execute('virsh',
+                                         '-c',
+                                         'lxc:///',
+                                         'ttyconsole',
+                                         instance['name'])
+            data = self._flush_libvirt_console(virsh_output)
+            fpath = self._append_to_file(data, console_log)
         else:
             fpath = console_log