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webvirtcloud/instances/test_live_dataloss.py
catborise 21f0777e76 fix(instances): internal snapshots no longer rewrite UEFI loaders
Taking or reverting an internal snapshot redefined a pflash VM with a
rom loader around the operation. libvirt 10.10 rejects that definition,
so the request ended in a 500; where it was accepted, the snapshot
recorded the fake loader, and a failure between rewrite and restore
left the VM unable to boot.

The definition is no longer touched: libvirt decides, and its error is
shown (for a running VM with raw NVRAM: 'internal snapshots of a VM
with pflash based firmware require QCOW2 nvram format'). A stopped VM's
disk-only internal snapshot is taken, as libvirt allows it. Revert
errors are shown too. The external snapshot path keeps its rewrite for
now.

Live tests cover running and stopped UEFI VMs; both failed with a 500
on the previous code.
2026-10-04 01:08:11 +03:00

270 lines
10 KiB
Python

"""Live reproductions of the Wave 1a data-loss findings.
Each test asserts the safe behavior and is marked expectedFailure until
its finding is fixed; a fix turns it into an unexpected success, which
fails the run until the marker is removed. Runs only with
TEST_LIBVIRT_HOST set (see instances/livetest.py).
"""
import os
import unittest
import libvirt
from computes.models import Compute
from django.contrib.auth import get_user_model
from django.contrib.messages import get_messages
from django.test import TestCase
from django.urls import reverse
from vrtManager.connection import connection_manager
from . import livetest
from .models import Instance
from .utils import refr
P = livetest.PREFIX
class LiveDataLossTestCase(TestCase):
@classmethod
def setUpClass(cls):
if not livetest.enabled():
raise unittest.SkipTest("Set TEST_LIBVIRT_HOST to run the live libvirt tests")
cls.compute_args = dict(
hostname=os.environ["TEST_LIBVIRT_HOST"],
login=os.environ.get("TEST_LIBVIRT_LOGIN", ""),
password=os.environ.get("TEST_LIBVIRT_PASSWORD", ""),
type=int(os.environ.get("TEST_LIBVIRT_TYPE", 4)),
)
cls.conn = connection_manager.get_connection(*cls.compute_args.values())
livetest.cleanup(cls.conn)
livetest.ensure_pool(cls.conn)
cls.inventory = livetest.inventory(cls.conn)
# Last: a failure above must not leave the class transaction open,
# which would lock the shared test database for later test classes.
super().setUpClass()
@classmethod
def tearDownClass(cls):
try:
livetest.remove_pool(cls.conn)
finally:
super().tearDownClass()
if livetest.inventory(cls.conn) != cls.inventory:
raise AssertionError("Live tests changed objects outside the test namespace")
def setUp(self):
self.compute = Compute.objects.create(name="live-dataloss", details="test", **self.compute_args)
admin = get_user_model().objects.create_superuser("live_admin", "l@example.com", "pw")
self.client.force_login(admin)
self.client.raise_request_exception = False
def tearDown(self):
livetest.cleanup(self.conn)
# helpers
def vm(self, name, disks, uefi=False):
dom = livetest.define_vm(self.conn, P + name, disks, uefi=uefi)
refr(self.compute)
return dom, Instance.objects.get(compute=self.compute, uuid=dom.UUIDString())
def post(self, view, instance, data=None):
return self.client.post(
reverse(f"instances:{view}", args=[instance.id]),
data or {},
HTTP_REFERER=reverse("instances:instance", args=[instance.id]),
)
def disk_sources(self, dom, flags=0):
from lxml import etree
return {
d.find("target").get("dev"): d.find("source").get("file")
for d in etree.fromstring(dom.XMLDesc(flags)).findall("devices/disk")
}
def domain_exists(self, uuid):
try:
self.conn.lookupByUUIDString(uuid)
return True
except libvirt.libvirtError:
return False
# R-03: external snapshots
@unittest.expectedFailure
def test_r03_revert_external_snapshot_keeps_disk_added_later(self):
base = livetest.create_volume(self.conn, P + "r03-a")
dom, inst = self.vm("r03-a", [base])
self.post("create_external_snapshot", inst, {"name": "snap"})
later = livetest.create_volume(self.conn, P + "r03-later")
dom.attachDeviceFlags(
f"<disk type='file' device='disk'><driver name='qemu' type='qcow2'/>"
f"<source file='{later}'/><target dev='vdb' bus='virtio'/></disk>",
libvirt.VIR_DOMAIN_AFFECT_CONFIG,
)
self.post("revert_external_snapshot", inst, {"name": "s1.snap", "date": "", "desc": ""})
self.assertTrue(livetest.volume_exists(self.conn, later), "revert deleted a disk the snapshot never had")
@unittest.expectedFailure
def test_r03_delete_older_external_snapshot_keeps_newer_snapshot_files(self):
base = livetest.create_volume(self.conn, P + "r03-b")
dom, inst = self.vm("r03-b", [base])
self.post("create_external_snapshot", inst, {"name": "older"})
self.post("create_external_snapshot", inst, {"name": "newer"})
sources = set(self.disk_sources(dom).values())
self.post("delete_external_snapshot", inst, {"name": "s1.older"})
for path in sources:
self.assertTrue(livetest.volume_exists(self.conn, path), f"{path} was deleted")
self.assertIn("s1.newer", dom.snapshotListNames(0))
# R-13: internal snapshots of UEFI VMs
def _uefi_internal_snapshot(self, running):
base = livetest.create_volume(self.conn, P + "r13")
dom, inst = self.vm("r13", [base], uefi=True)
if running:
dom.create()
os_before = self.os_xml(dom)
response = self.post("snapshot", inst, {"name": "snap"})
# Taken where libvirt supports it, otherwise refused with a message;
# never a server error and never a rewritten loader or NVRAM.
self.assertEqual(response.status_code, 302)
if dom.snapshotNum(0) == 0:
self.assertTrue(list(get_messages(response.wsgi_request)))
self.assertEqual(self.os_xml(dom), os_before)
def os_xml(self, dom):
from lxml import etree
return etree.tostring(etree.fromstring(dom.XMLDesc(libvirt.VIR_DOMAIN_XML_INACTIVE)).find("os"))
def test_r13_uefi_internal_snapshot_of_a_stopped_vm(self):
self._uefi_internal_snapshot(running=False)
def test_r13_uefi_internal_snapshot_of_a_running_vm(self):
self._uefi_internal_snapshot(running=True)
# R-14: destroy
def test_r14_destroy_keeps_a_volume_another_vm_uses(self):
shared = livetest.create_volume(self.conn, P + "r14-shared")
_, inst = self.vm("r14-a", [shared])
self.vm("r14-b", [shared])
response = self.post("destroy", inst, {"delete_disk": "1"})
self.assertEqual(response.status_code, 302)
self.assertTrue(livetest.volume_exists(self.conn, shared), "destroy deleted another VM's disk")
def _destroy_base_of_another_vms_overlay(self, running):
base = livetest.create_volume(self.conn, P + "r14-base")
pool = self.conn.storagePoolLookupByName(livetest.POOL)
overlay = pool.createXML(
f"<volume><name>{P}r14-overlay.qcow2</name><capacity unit='MiB'>64</capacity>"
f"<target><format type='qcow2'/></target><backingStore><path>{base}</path>"
"<format type='qcow2'/></backingStore></volume>",
0,
).path()
_, inst = self.vm("r14-base", [base])
dom_b, _ = self.vm("r14-overlay", [overlay])
if running:
dom_b.create()
response = self.post("destroy", inst, {"delete_disk": "1"})
self.assertEqual(response.status_code, 302)
self.assertTrue(livetest.volume_exists(self.conn, base), "deleted the backing file of another VM's disk")
def test_r14_destroy_keeps_the_backing_file_of_a_stopped_vm(self):
self._destroy_base_of_another_vms_overlay(running=False)
def test_r14_destroy_keeps_the_backing_file_of_a_running_vm(self):
self._destroy_base_of_another_vms_overlay(running=True)
def test_r14_destroy_with_managed_save_removes_the_vm(self):
base = livetest.create_volume(self.conn, P + "r14-save")
dom, inst = self.vm("r14-save", [base])
dom.create()
dom.managedSave(0)
self.post("destroy", inst, {"delete_disk": "1"})
uuid = dom.UUIDString()
self.assertFalse(self.domain_exists(uuid), "VM is still defined")
self.assertFalse(Instance.objects.filter(uuid=uuid).exists())
def test_r14_destroy_of_a_paused_vm_removes_it(self):
base = livetest.create_volume(self.conn, P + "r14-paused")
dom, inst = self.vm("r14-paused", [base])
dom.create()
dom.suspend()
self.post("destroy", inst)
self.assertFalse(self.domain_exists(dom.UUIDString()), "paused VM is still running")
# S-02: delete a volume only after it is detached
def _delete_attached_volume(self, pause):
base = livetest.create_volume(self.conn, P + "s02")
data = livetest.create_volume(self.conn, P + "s02-data")
dom, inst = self.vm("s02", [base, data])
dom.create()
if pause:
dom.suspend()
response = self.post("delete_vol", inst, {"dev": "vdb"})
self.assertEqual(response.status_code, 302)
# The guest has no OS, so it never releases the disk: the live
# definition keeps vdb, and the volume must be kept with it.
self.assertIn("vdb", self.disk_sources(dom))
self.assertTrue(livetest.volume_exists(self.conn, data), "volume deleted while the VM still uses it")
def test_s02_delete_volume_of_a_paused_vm(self):
self._delete_attached_volume(pause=True)
def test_s02_delete_volume_of_a_running_vm_without_guest_ack(self):
self._delete_attached_volume(pause=False)
def test_s02_delete_volume_another_vm_uses_is_refused(self):
base = livetest.create_volume(self.conn, P + "s02-own")
shared = livetest.create_volume(self.conn, P + "s02-shared")
_, inst = self.vm("s02-a", [base, shared])
self.vm("s02-b", [shared])
response = self.post("delete_vol", inst, {"dev": "vdb"})
self.assertEqual(response.status_code, 302)
self.assertTrue(livetest.volume_exists(self.conn, shared), "deleted another VM's disk")
# R-06: operations follow the VM's UUID, not its name
def test_r06_mutation_follows_uuid_after_names_are_swapped(self):
dom_a, inst_a = self.vm("r06-a", [])
dom_b, _ = self.vm("r06-b", [])
dom_a.rename(P + "r06-tmp", 0)
dom_b.rename(P + "r06-a", 0)
dom_a.rename(P + "r06-b", 0)
self.post("change_options", inst_a, {"title": "for-a", "description": ""})
self.assertIn("<title>for-a</title>", dom_a.XMLDesc(0))
self.assertNotIn("<title>for-a</title>", dom_b.XMLDesc(0))
def test_r06_vm_replaced_under_the_same_name_is_not_touched(self):
dom_old, inst = self.vm("r06-c", [])
dom_old.undefine()
dom_new = livetest.define_vm(self.conn, P + "r06-c", [])
self.post("change_options", inst, {"title": "for-old", "description": ""})
self.assertNotIn("<title>for-old</title>", dom_new.XMLDesc(0))