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webvirtcloud/instances/test_live_dataloss.py
catborise ffb2ce6bfa fix(instances): destroy and volume delete no longer lose disks
Destroy:
- Stops every active state, not only running; a paused VM used to keep
  running as a transient domain after the undefine.
- Undefines with MANAGED_SAVE and SNAPSHOTS_METADATA, before any disk is
  deleted. A managed-save image used to make the undefine fail after the
  disks were already gone; now a failed undefine deletes nothing.
- Keeps disks that another domain references, directly or as a backing
  file anywhere in its chain (running domains' backingStore, and the
  backingStore of the volumes in the active pools for stopped ones), and
  says so; they used to be deleted with the VM.

Volume delete:
- Detaches from the live domain in every active state, including paused.
- Deletes the volume only after neither the live nor the persistent
  definition has the disk (bounded wait for the guest to release it),
  and refuses a volume another VM references. Otherwise the volume is
  kept and the user is told why.

Both hold the compute exclusively for the usage scan and the deletion,
so another VM cannot attach the disk in between; the destroy
confirmation page (GET) takes no lock.

Live tests reproduce each case on a RHEL qemu-kvm host and fail on the
previous code; unit tests cover the destroy ordering and the locks.
2026-10-04 01:08:11 +03:00

217 lines
8.4 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.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-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")