mirror of
https://github.com/retspen/webvirtcloud
synced 2026-11-08 19:26:48 +00:00
Two computes decide the owners of the same UUID: the one the VM left buries them in a tombstone (or a compute delete does), the one it went to restores them. On PostgreSQL the two ran at once: the restore still saw the old row of the uncommitted bury, skipped, and the VM ended up without owners while the tombstone stayed. SQLite was never affected: its IMMEDIATE transactions take the write lock at the start. The reconcile and the compute delete now take one transaction-level advisory lock (pg_advisory_xact_lock) when their database step starts, so ownership decisions run one after another on PostgreSQL as they do on SQLite. Reading libvirt stays outside the lock.
106 lines
3.6 KiB
Python
106 lines
3.6 KiB
Python
from ipaddress import ip_address
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from django.db import transaction
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from django.db.models import CharField, IntegerField, Model
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from django.utils.functional import cached_property
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from django.utils.translation import gettext_lazy as _
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from libvirt import virConnect
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from computes.validators import validate_hostname, validate_login, validate_migration_address
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from vrtManager.connection import connection_manager
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from vrtManager.hostdetails import wvmHostDetails
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class Compute(Model):
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name = CharField(_("name"), max_length=64, unique=True)
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hostname = CharField(_("hostname"), max_length=64, validators=[validate_hostname])
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login = CharField(_("login"), max_length=20, blank=True, validators=[validate_login])
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password = CharField(_("password"), max_length=14, blank=True, null=True)
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details = CharField(_("details"), max_length=64, null=True, blank=True)
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type = IntegerField()
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migration_address = CharField(
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_("migration address"),
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max_length=64,
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blank=True,
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default="",
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validators=[validate_migration_address],
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help_text=_(
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"IP address or host name the other hosts send migrating VMs to; "
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"empty: the host's own host name, which they must be able to resolve"
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),
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)
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@property
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def migration_uri(self):
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"""The native migration URI for VMs migrated to this host, or None for
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libvirt's default."""
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if not self.migration_address:
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return None
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try:
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if ip_address(self.migration_address).version == 6:
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return f"tcp://[{self.migration_address}]"
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except ValueError:
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pass
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return f"tcp://{self.migration_address}"
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@cached_property
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def status(self):
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"""True if WebVirtCloud can connect to the host (within the connect
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timeout; a host that failed recently is not tried again at once)."""
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return isinstance(self.connection, virConnect)
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@cached_property
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def connection_error(self):
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"""Why the host cannot be reached, or None."""
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return None if self.status else str(self.connection)
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@cached_property
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def connection(self):
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try:
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return connection_manager.get_connection(
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self.hostname,
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self.login,
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self.password,
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self.type,
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)
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except Exception as e:
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return e
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@cached_property
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def proxy(self):
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return wvmHostDetails(
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self.hostname,
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self.login,
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self.password,
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self.type,
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)
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@cached_property
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def cpu_count(self):
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return self.proxy.get_node_info()[3]
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@cached_property
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def ram_size(self):
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return self.proxy.get_node_info()[2]
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@cached_property
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def ram_usage(self):
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return self.proxy.get_memory_usage()["percent"]
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def __str__(self):
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return self.name
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def delete(self, *args, **kwargs):
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"""Its VMs keep running on the host: their owners wait in tombstones,
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or follow a VM already listed on another compute. The compute is held
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exclusive, so no reconcile, VM operation or job on it runs meanwhile
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(Busy if one does); its row is locked before its VMs', as the
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reconcile does."""
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from computes.utils import forget, libvirt_compute_lock, lock_ownership
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with libvirt_compute_lock(self), transaction.atomic():
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lock_ownership()
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Compute.objects.select_for_update().filter(pk=self.pk).first()
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for inst in self.instance_set.select_for_update():
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forget(inst)
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return super().delete(*args, **kwargs)
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