From dec5dd9286e0d218d3f7658879369b5d4a529a65 Mon Sep 17 00:00:00 2001
From: Kevin_Zheng <zhengzhenyu@huawei.com>
Date: Mon, 26 Nov 2018 11:47:33 +0800
Subject: [PATCH] Per-instance serial number

Added a new ``unique`` choice to the ``[libvirt]/sysinfo_serial``
configuration which if set will result in the guest serial number
being set to ``instance.uuid`` on this host. It is also made to be
the default value of ``[libvirt]/sysinfo_serial`` config option.

Implements: blueprint per-instance-libvirt-sysinfo-serial

Change-Id: I001beb2840496f7950988acc69018244847aa888
---
 nova/conf/libvirt.py                             | 16 +++++++++++++---
 nova/tests/unit/virt/libvirt/test_driver.py      |  6 ++++++
 nova/virt/libvirt/driver.py                      |  5 ++++-
 .../per-instance-serial-f2e597cb05d1b09e.yaml    |  7 +++++++
 4 files changed, 30 insertions(+), 4 deletions(-)
 create mode 100644 releasenotes/notes/per-instance-serial-f2e597cb05d1b09e.yaml

diff --git a/nova/conf/libvirt.py b/nova/conf/libvirt.py
index 3f368f9aa89d..4d87ea616a75 100644
--- a/nova/conf/libvirt.py
+++ b/nova/conf/libvirt.py
@@ -716,21 +716,31 @@ http://man7.org/linux/man-pages/man7/random.7.html.
                      'value for this config option is host-arch=machine-type. '
                      'For example: x86_64=machinetype1,armv7l=machinetype2'),
     cfg.StrOpt('sysinfo_serial',
-               default='auto',
+               default='unique',
                choices=(
                    ('none', 'A serial number entry is not added to the guest '
                             'domain xml.'),
                    ('os', 'A UUID serial number is generated from the host '
-                          '``/etc/machine-id`` file.'),
+                          '``/etc/machine-id`` file. This will also affect '
+                          'existing instances on this host once they stop '
+                          'and start again.'),
                    ('hardware', 'A UUID for the host hardware as reported by '
                                 'libvirt. This is typically from the host '
                                 'SMBIOS data, unless it has been overridden '
                                 'in ``libvirtd.conf``.'),
                    ('auto', 'Uses the "os" source if possible, else '
                             '"hardware".'),
+                   ('unique', 'Uses instance UUID as the serial number. '
+                              'This will also affect existing instances '
+                              'on this host once they stop and start again.'),
                ),
                help='The data source used to the populate the host "serial" '
-                    'UUID exposed to guest in the virtual BIOS.'),
+                    'UUID exposed to guest in the virtual BIOS. All choices '
+                    'except ``unique`` will change the serial when migrating '
+                    'instance to other host. Changing the choice of this '
+                    'option will also affect existing instances on this host '
+                    'once they stopped and started again.'
+               ),
     cfg.IntOpt('mem_stats_period_seconds',
                default=10,
                help='A number of seconds to memory usage statistics period. '
diff --git a/nova/tests/unit/virt/libvirt/test_driver.py b/nova/tests/unit/virt/libvirt/test_driver.py
index 84d05a55c280..12c3e82f86bb 100644
--- a/nova/tests/unit/virt/libvirt/test_driver.py
+++ b/nova/tests/unit/virt/libvirt/test_driver.py
@@ -17927,6 +17927,8 @@ class TestGuestConfigSysinfoSerialOS(test.NoDBTestCase):
                          cfg.system_product)
         self.assertEqual(version.version_string_with_package(),
                          cfg.system_version)
+        if expected_serial == 'instance_uuid':
+            expected_serial = instance_ref['uuid']
         self.assertEqual(expected_serial,
                          cfg.system_serial)
         self.assertEqual(instance_ref['uuid'],
@@ -18025,6 +18027,10 @@ class TestGuestConfigSysinfoSerialOS(test.NoDBTestCase):
 
             self._test_get_guest_config_sysinfo_serial(theuuid)
 
+    def test_get_guest_config_sysinfo_serial_unique(self):
+        self.flags(sysinfo_serial="unique", group="libvirt")
+        self._test_get_guest_config_sysinfo_serial('instance_uuid')
+
 
 class HostStateTestCase(test.NoDBTestCase):
 
diff --git a/nova/virt/libvirt/driver.py b/nova/virt/libvirt/driver.py
index e762b27b8c25..0d18bc5663ad 100644
--- a/nova/virt/libvirt/driver.py
+++ b/nova/virt/libvirt/driver.py
@@ -4154,7 +4154,10 @@ class LibvirtDriver(driver.ComputeDriver):
         sysinfo.system_product = version.product_string()
         sysinfo.system_version = version.version_string_with_package()
 
-        sysinfo.system_serial = self._sysinfo_serial_func()
+        if CONF.libvirt.sysinfo_serial == 'unique':
+            sysinfo.system_serial = instance.uuid
+        else:
+            sysinfo.system_serial = self._sysinfo_serial_func()
         sysinfo.system_uuid = instance.uuid
 
         sysinfo.system_family = "Virtual Machine"
diff --git a/releasenotes/notes/per-instance-serial-f2e597cb05d1b09e.yaml b/releasenotes/notes/per-instance-serial-f2e597cb05d1b09e.yaml
new file mode 100644
index 000000000000..66ac2f4bab8a
--- /dev/null
+++ b/releasenotes/notes/per-instance-serial-f2e597cb05d1b09e.yaml
@@ -0,0 +1,7 @@
+---
+upgrade:
+  - |
+    Added a new ``unique`` choice to the ``[libvirt]/sysinfo_serial``
+    configuration which if set will result in the guest serial number being
+    set to ``instance.uuid`` on this host. This is now the default value
+    of ``[libvirt]/sysinfo_serial`` config option.