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webvirtcloud/instances/utils.py
catborise 975b7f0baf fix(migration): remove the NVRAM file a live migration leaves on the source
libvirt undefines the source domain after a migration but keeps its NVRAM
file. A VM created later on that host with the same name reuses the file
and starts with the old VM's UEFI variables (boot entries, enrolled keys):
checked on libvirt 11.10, where only VIR_DOMAIN_START_RESET_NVRAM
recreates it from the template.

After a successful migration the file is now deleted on the source, as a
volume of the pool on libvirt's NVRAM directory or of a transient one.
Only a file in /var/lib/libvirt/qemu/nvram, and only when the destination
cannot create a marker file the source just created there (an exclusive
create also fails on shared storage whose listing an NFS client caches).
A failed removal is logged with the migration, which stands and is
recorded.
2026-10-09 07:29:10 +03:00

395 lines
14 KiB
Python

import os
import random
import re
import string
from accounts.models import UserInstance, UserAttributes
from appsettings.settings import app_settings
from computes.utils import libvirt_compute_lock
from django.conf import settings
from django.db import transaction
from django.utils.translation import gettext_lazy as _
from libvirt import libvirtError
from logs.views import addlogmsg
from vrtManager import util
from vrtManager.instance import wvmInstance, wvmInstances
from .models import Instance
def can_open_console(user, instance):
"""
The single rule for console access (noVNC page, novncd, the virt-viewer
.vv file and the VDI URL): an active superuser or an active owner of the
VM. The global view_instances permission is read-only and does not grant
an interactive console.
"""
if not user.is_active:
return False
if user.is_superuser:
return True
return UserInstance.objects.filter(instance=instance, user=user).exists()
def get_clone_free_names(size=10):
prefix = app_settings.CLONE_INSTANCE_DEFAULT_PREFIX
free_names = []
existing_names = [i.name for i in Instance.objects.filter(name__startswith=prefix)]
index = 1
while len(free_names) < size:
new_name = prefix + str(index)
if new_name not in existing_names:
free_names.append(new_name)
index += 1
return free_names
# check_user_quota could not read every VM of the user: an increase is refused
QUOTA_UNVERIFIED = "unverified"
def check_user_quota(user, instance, cpu, memory, disk_size):
"""
Which quota the user would exceed by adding these amounts (instances,
vCPUs, memory MiB, disk GiB) to their VMs, or "". QUOTA_UNVERIFIED if a
VM that counts cannot be read (its host is down, the VM is gone): the
usage is unknown, so an increase is refused.
"""
ua, attributes_created = UserAttributes.objects.get_or_create(user=user)
msg = ""
if user.is_superuser:
return msg
# adding nothing (a shrink) cannot exceed a quota
if instance <= 0 and cpu <= 0 and memory <= 0 and disk_size <= 0:
return msg
quota_debug = app_settings.QUOTA_DEBUG
user_instances = UserInstance.objects.filter(user=user, instance__is_template=False).select_related(
"instance__compute"
)
instance += user_instances.count()
if ua.max_instances > 0 and instance > ua.max_instances:
msg = "instance"
if quota_debug:
msg += f" ({instance} > {ua.max_instances})"
return msg
if ua.max_cpus <= 0 and ua.max_memory <= 0 and ua.max_disk_size <= 0:
return msg
computes = {} # status is cached per object: check each host once
for usr_inst in user_instances:
vm = usr_inst.instance
compute = computes.setdefault(vm.compute_id, vm.compute)
if compute.status is not True:
return QUOTA_UNVERIFIED
try:
conn = wvmInstance(
compute.hostname,
compute.login,
compute.password,
compute.type,
vm.name,
uuid=vm.uuid,
)
cpu += int(conn.get_vcpu())
memory += int(conn.get_memory())
for disk in conn.get_disk_devices():
if disk["size"]:
disk_size += int(disk["size"]) >> 30
except libvirtError:
return QUOTA_UNVERIFIED
if ua.max_cpus > 0 and cpu > ua.max_cpus:
msg = "cpu"
if quota_debug:
msg += f" ({cpu} > {ua.max_cpus})"
if ua.max_memory > 0 and memory > ua.max_memory:
msg = "memory"
if quota_debug:
msg += f" ({memory} > {ua.max_memory})"
if ua.max_disk_size > 0 and disk_size > ua.max_disk_size:
msg = "disk"
if quota_debug:
msg += f" ({disk_size} > {ua.max_disk_size})"
return msg
def get_new_disk_dev(media, disks, bus):
existing_disk_devs = []
existing_media_devs = []
if bus == "virtio":
dev_base = "vd"
elif bus == "ide":
dev_base = "hd"
elif bus == "fdc":
dev_base = "fd"
else:
dev_base = "sd"
if disks:
existing_disk_devs = [disk["dev"] for disk in disks]
# cd-rom bus could be virtio/sata, because of that we should check it also
if media:
existing_media_devs = [m["dev"] for m in media]
for al in string.ascii_lowercase:
dev = dev_base + al
if dev not in existing_disk_devs and dev not in existing_media_devs:
return dev
raise Exception(_("None available device name"))
def get_network_tuple(network_source_str):
network_source_pack = network_source_str.split(":", 1)
if len(network_source_pack) > 1:
return network_source_pack[1], network_source_pack[0]
else:
return network_source_pack[0], "net"
# A migration that has not finished by then is cancelled: below the 600 s
# after which gunicorn (gunicorn.conf.py) ends the request.
MIGRATION_TIME_LIMIT = 540
def migrate_instance(
new_compute,
instance,
user,
live=False,
unsafe=False,
offline=False,
autoconverge=False,
compress=False,
):
"""Migrates instance to new_compute and logs the outcome (the mode
used, or the error). Returns the mode."""
if new_compute == instance.compute:
raise util.OperationError(_("The instance is already on %(compute)s") % {"compute": new_compute.name})
if not new_compute.status:
raise util.OperationError(_("%(compute)s is not reachable") % {"compute": new_compute.name})
source = instance.compute
c1, c2 = (source, new_compute) if source.id < new_compute.id else (new_compute, source)
with libvirt_compute_lock(c1):
with libvirt_compute_lock(c2):
# another request may have moved it while this one waited (its
# record may then be gone, merged into one on the destination)
current = Instance.objects.filter(id=instance.id).first()
if current is None or current.compute_id != source.id:
raise util.OperationError(_("The instance is no longer on %(compute)s") % {"compute": source.name})
conn_migrate = None
try:
conn_migrate = wvmInstances(
new_compute.hostname,
new_compute.login,
new_compute.password,
new_compute.type,
)
autostart = instance.proxy.get_autostart()
nvram = instance.proxy.get_nvram()
mode = conn_migrate.moveto(
instance.proxy,
instance.name,
live,
unsafe,
offline,
autoconverge,
compress,
uri=new_compute.migration_uri,
timeout=MIGRATION_TIME_LIMIT,
)
except Exception as error:
msg = _("Instance migration to %(target)s failed: %(error)s") % {
"target": migration_target(new_compute),
"error": error,
}
addlogmsg(user.username, source.hostname, instance.name, msg)
raise
finally:
if conn_migrate is not None:
conn_migrate.close()
# The VM runs on new_compute now: what follows must not stop it
# from being recorded there.
msg = _("Instance is migrated(%(mode)s) to %(target)s") % {
"mode": mode,
"target": migration_target(new_compute),
}
if autostart:
conn_new = None
try:
conn_new = wvmInstance(
new_compute.hostname,
new_compute.login,
new_compute.password,
new_compute.type,
instance.name,
uuid=instance.uuid,
)
conn_new.set_autostart(1)
except (libvirtError, OSError) as error:
msg = _("%(msg)s; setting its autostart there failed: %(error)s") % {"msg": msg, "error": error}
finally:
if conn_new is not None:
conn_new.close()
# libvirt keeps the NVRAM file on the source; a VM created there
# later with the same name would start with these variables.
if nvram:
conn_new = None
try:
conn_new = wvmInstances(
new_compute.hostname, new_compute.login, new_compute.password, new_compute.type
)
instance.proxy.remove_nvram(nvram, conn_new)
except Exception as error: # the migration stands and is recorded
msg = _("%(msg)s; removing its NVRAM file %(path)s on the source failed: %(error)s") % {
"msg": msg,
"path": nvram,
"error": error,
}
finally:
if conn_new is not None:
conn_new.close()
try:
record_migration(instance, new_compute)
except Exception as error:
failed = _("%(msg)s, but recording it failed: %(error)s") % {"msg": msg, "error": error}
addlogmsg(user.username, source.hostname, instance.name, failed)
raise
addlogmsg(user.username, source.hostname, instance.name, msg)
return mode
def record_migration(instance, new_compute):
"""Moves instance to new_compute in the database. A record the list of
new_compute made for it meanwhile takes its owners and template mark."""
with transaction.atomic():
target_inst = Instance.objects.filter(compute=new_compute, uuid=instance.uuid).first()
if target_inst and target_inst.id != instance.id:
for ui in UserInstance.objects.filter(instance=instance):
existing_ui = UserInstance.objects.filter(instance=target_inst, user=ui.user).first()
if not existing_ui:
ui.instance = target_inst
ui.save()
else:
updated = False
if ui.is_change and not existing_ui.is_change:
existing_ui.is_change = True
updated = True
if ui.is_delete and not existing_ui.is_delete:
existing_ui.is_delete = True
updated = True
if ui.is_vnc and not existing_ui.is_vnc:
existing_ui.is_vnc = True
updated = True
if updated:
existing_ui.save()
ui.delete()
if instance.is_template and not target_inst.is_template:
target_inst.is_template = True
target_inst.save(update_fields=["is_template"])
instance.delete()
instance.id = target_inst.id
instance.compute = new_compute
else:
instance.compute = new_compute
instance.save()
def migration_target(compute):
"""The destination for the log: its host name, and the migration address
when one is set and differs."""
if compute.migration_address not in ("", compute.hostname):
return _("%(hostname)s via %(address)s") % {"hostname": compute.hostname, "address": compute.migration_address}
return compute.hostname
def refr(compute):
from computes.utils import refresh_instance_database
refresh_instance_database(compute)
def dhcpd_conf():
"""Optional dhcpd.conf in the application directory; clone names and MAC
addresses are taken from its host entries when it exists."""
return os.path.join(str(settings.BASE_DIR), "dhcpd.conf")
def get_dhcp_mac_address(vname):
dhcp_file = dhcpd_conf()
mac = ""
if os.path.isfile(dhcp_file):
with open(dhcp_file, "r") as f:
name_found = False
for line in f:
if "host %s." % vname in line:
name_found = True
if name_found and "hardware ethernet" in line:
mac = line.split(" ")[-1].strip().strip(";")
break
return mac
MAC_ADDRESS_RE = re.compile(r"^([0-9A-F]{2})(:?[0-9A-F]{2}){5}$", re.IGNORECASE)
def nic_macs(mac, networks):
"""The MAC addresses given for a new VM's NICs, in network order. NICs
without one get theirs from libvirt."""
macs = [m.strip() for m in mac.split(",")] if mac else []
if not all(MAC_ADDRESS_RE.fullmatch(m) for m in macs):
raise ValueError(_("Invalid MAC address"))
if len(macs) > len(networks.split(",")):
raise ValueError(_("More MAC addresses than networks"))
return macs
def get_random_mac_address():
mac = settings.MAC_OUI + ":%02x:%02x:%02x" % (
random.randint(0x00, 0xFF),
random.randint(0x00, 0xFF),
random.randint(0x00, 0xFF),
)
return mac
def get_clone_disk_name(disk, prefix, clone_name=""):
if not disk["image"]:
return None
if disk["image"].startswith(prefix) and clone_name:
suffix = disk["image"][len(prefix) :]
image = f"{clone_name}{suffix}"
elif "." in disk["image"] and len(disk["image"].rsplit(".", 1)[1]) <= 7:
name, suffix = disk["image"].rsplit(".", 1)
image = f"{name}-clone.{suffix}"
else:
image = f"{disk['image']}-clone"
# Derived names go into volume XML and paths: keep them to a safe charset.
image = re.sub(r"[^A-Za-z0-9_.+-]+", "-", image).lstrip("_.+-")
return image or None
def can_manage_console(user, instance):
"""
Who may see and change a VM's console settings, including its VNC
password: an active superuser, or an active owner with both is_change and
is_vnc; on a template only a staff owner (as get_instance(perm_type="change")).
is_staff and the global view_instances permission alone do not count.
"""
if not user.is_active:
return False
if user.is_superuser:
return True
if instance.is_template and not user.is_staff:
return False
return UserInstance.objects.filter(
instance=instance, user=user, is_change=True, is_vnc=True
).exists()