def _schedule(self, context, topic, request_spec, filter_properties):
"""Picks a host that is up at random."""
elevated = context.elevated()
hosts = self.hosts_up(elevated, topic)
if not hosts:
msg = _("Is the appropriate service running?")
raise exception.NoValidHost(reason=msg)
hosts = self._filter_hosts(request_spec, hosts, filter_properties)
if not hosts:
msg = _("Could not find another compute")
raise exception.NoValidHost(reason=msg)
return random.choice(hosts)
def select_destinations(self, context, request_spec, filter_properties):
"""Selects a filtered set of hosts and nodes."""
self.notifier.info(context, 'scheduler.select_destinations.start',
dict(request_spec=request_spec))
num_instances = request_spec['num_instances']
selected_hosts = self._schedule(context, request_spec,
filter_properties)
# Couldn't fulfill the request_spec
if len(selected_hosts) < num_instances:
# Log the details but don't put those into the reason since
# we don't want to give away too much information about our
# actual environment.
LOG.debug(
'There are %(hosts)d hosts available but '
'%(num_instances)d instances requested to build.', {
'hosts': len(selected_hosts),
'num_instances': num_instances
})
reason = _('There are not enough hosts available.')
raise exception.NoValidHost(reason=reason)
dests = [
dict(host=host.obj.host,
nodename=host.obj.nodename,
limits=host.obj.limits) for host in selected_hosts
]
self.notifier.info(context, 'scheduler.select_destinations.end',
dict(request_spec=request_spec))
return dests
def populate_retry(filter_properties, instance_uuid):
max_attempts = _max_attempts()
force_hosts = filter_properties.get('force_hosts', [])
force_nodes = filter_properties.get('force_nodes', [])
# In the case of multiple force hosts/nodes, scheduler should not
# disable retry filter but traverse all force hosts/nodes one by
# one till scheduler gets a valid target host.
if (max_attempts == 1 or len(force_hosts) == 1 or len(force_nodes) == 1):
# re-scheduling is disabled.
return
# retry is enabled, update attempt count:
retry = filter_properties.setdefault(
'retry',
{
'num_attempts': 0,
'hosts': [] # list of compute hosts tried
})
retry['num_attempts'] += 1
_log_compute_error(instance_uuid, retry)
exc = retry.pop('exc', None)
if retry['num_attempts'] > max_attempts:
msg = (_('Exceeded max scheduling attempts %(max_attempts)d '
'for instance %(instance_uuid)s. '
'Last exception: %(exc)s') % {
'max_attempts': max_attempts,
'instance_uuid': instance_uuid,
'exc': exc
})
raise exception.NoValidHost(reason=msg)
def test_setup_instance_group_with_filter_not_configured(self, mock_ggd):
mock_ggd.side_effect = exception.NoValidHost(reason='whatever')
spec = {'instance_properties': {'uuid': 'fake-uuid'}}
filter_props = {'group_hosts': ['hostC']}
self.assertRaises(exception.NoValidHost,
scheduler_utils.setup_instance_group, self.context,
spec, filter_props)
def _check_not_over_max_retries(self, attempted_hosts):
if CONF.migrate_max_retries == -1:
return
retries = len(attempted_hosts) - 1
if retries > CONF.migrate_max_retries:
msg = (_('Exceeded max scheduling retries %(max_retries)d for '
'instance %(instance_uuid)s during live migration') % {
'max_retries': retries,
'instance_uuid': self.instance.uuid
})
raise exception.NoValidHost(reason=msg)
def select_destinations(self, context, request_spec, filter_properties):
"""Selects random destinations."""
num_instances = request_spec['num_instances']
# NOTE(timello): Returns a list of dicts with 'host', 'nodename' and
# 'limits' as keys for compatibility with filter_scheduler.
dests = []
for i in range(num_instances):
host = self._schedule(context, CONF.compute_topic,
request_spec, filter_properties)
host_state = dict(host=host, nodename=None, limits=None)
dests.append(host_state)
if len(dests) < num_instances:
raise exception.NoValidHost(reason='')
return dests
def test_find_destination_when_runs_out_of_hosts(self):
self.mox.StubOutWithMock(compute_utils, 'get_image_metadata')
self.mox.StubOutWithMock(scheduler_utils, 'build_request_spec')
self.mox.StubOutWithMock(scheduler_utils, 'setup_instance_group')
self.mox.StubOutWithMock(self.task.scheduler_client,
'select_destinations')
compute_utils.get_image_metadata(self.context, self.task.image_api,
self.instance_image,
self.instance).AndReturn("image")
scheduler_utils.build_request_spec(self.context, mox.IgnoreArg(),
mox.IgnoreArg()).AndReturn({})
scheduler_utils.setup_instance_group(
self.context, {}, {'ignore_hosts': [self.instance_host]})
self.task.scheduler_client.select_destinations(
self.context, mox.IgnoreArg(),
mox.IgnoreArg()).AndRaise(exception.NoValidHost(reason=""))
self.mox.ReplayAll()
self.assertRaises(exception.NoValidHost, self.task._find_destination)
def _host_find(context, session, src_aggregate, host_ref):
"""Return the host from the xenapi host reference.
:param src_aggregate: the aggregate that the compute host being put in
maintenance (source of VMs) belongs to
:param host_ref: the hypervisor host reference (destination of VMs)
:return: the compute host that manages host_ref
"""
# NOTE: this would be a lot simpler if patron-compute stored
# CONF.host in the XenServer host's other-config map.
# TODO(armando-migliaccio): improve according the note above
uuid = session.host.get_uuid(host_ref)
for compute_host, host_uuid in src_aggregate.metadetails.iteritems():
if host_uuid == uuid:
return compute_host
raise exception.NoValidHost(reason='Host %(host_uuid)s could not be found '
'from aggregate metadata: %(metadata)s.' % {
'host_uuid': uuid,
'metadata': src_aggregate.metadetails
})
def _cold_migrate(self, context, instance, flavor, filter_properties,
reservations, clean_shutdown):
image_ref = instance.image_ref
image = compute_utils.get_image_metadata(
context, self.image_api, image_ref, instance)
request_spec = scheduler_utils.build_request_spec(
context, image, [instance], instance_type=flavor)
quotas = objects.Quotas.from_reservations(context,
reservations,
instance=instance)
try:
scheduler_utils.setup_instance_group(context, request_spec,
filter_properties)
scheduler_utils.populate_retry(filter_properties, instance['uuid'])
hosts = self.scheduler_client.select_destinations(
context, request_spec, filter_properties)
host_state = hosts[0]
except exception.NoValidHost as ex:
vm_state = instance.vm_state
if not vm_state:
vm_state = vm_states.ACTIVE
updates = {'vm_state': vm_state, 'task_state': None}
self._set_vm_state_and_notify(context, instance.uuid,
'migrate_server',
updates, ex, request_spec)
quotas.rollback()
# if the flavor IDs match, it's migrate; otherwise resize
if flavor['id'] == instance['instance_type_id']:
msg = _("No valid host found for cold migrate")
else:
msg = _("No valid host found for resize")
raise exception.NoValidHost(reason=msg)
except exception.UnsupportedPolicyException as ex:
with excutils.save_and_reraise_exception():
vm_state = instance.vm_state
if not vm_state:
vm_state = vm_states.ACTIVE
updates = {'vm_state': vm_state, 'task_state': None}
self._set_vm_state_and_notify(context, instance.uuid,
'migrate_server',
updates, ex, request_spec)
quotas.rollback()
try:
scheduler_utils.populate_filter_properties(filter_properties,
host_state)
# context is not serializable
filter_properties.pop('context', None)
(host, node) = (host_state['host'], host_state['nodename'])
self.compute_rpcapi.prep_resize(
context, image, instance,
flavor, host,
reservations, request_spec=request_spec,
filter_properties=filter_properties, node=node,
clean_shutdown=clean_shutdown)
except Exception as ex:
with excutils.save_and_reraise_exception():
updates = {'vm_state': instance.vm_state,
'task_state': None}
self._set_vm_state_and_notify(context, instance.uuid,
'migrate_server',
updates, ex, request_spec)
quotas.rollback()
def test_migrate_live_no_valid_host(self):
self._test_migrate_live_failed_with_exception(
exception.NoValidHost(reason=''))
def host_maintenance_mode(self, host, mode):
"""Start/Stop host maintenance window. On start, it triggers
guest VMs evacuation.
"""
if not mode:
return 'off_maintenance'
host_list = [
host_ref for host_ref in self._session.host.get_all()
if host_ref != self._session.host_ref
]
migrations_counter = vm_counter = 0
ctxt = context.get_admin_context()
for vm_ref, vm_rec in vm_utils.list_vms(self._session):
for host_ref in host_list:
try:
# Ensure only guest instances are migrated
uuid = vm_rec['other_config'].get('patron_uuid')
if not uuid:
name = vm_rec['name_label']
uuid = _uuid_find(ctxt, host, name)
if not uuid:
LOG.info(
_LI('Instance %(name)s running on '
'%(host)s could not be found in '
'the database: assuming it is a '
'worker VM and skip ping migration '
'to a new host'), {
'name': name,
'host': host
})
continue
instance = objects.Instance.get_by_uuid(ctxt, uuid)
vm_counter = vm_counter + 1
aggregate = objects.AggregateList.get_by_host(
ctxt, host, key=pool_states.POOL_FLAG)
if not aggregate:
msg = _('Aggregate for host %(host)s count not be'
' found.') % dict(host=host)
raise exception.NotFound(msg)
dest = _host_find(ctxt, self._session, aggregate[0],
host_ref)
instance.host = dest
instance.task_state = task_states.MIGRATING
instance.save()
self._session.VM.pool_migrate(vm_ref, host_ref,
{"live": "true"})
migrations_counter = migrations_counter + 1
instance.vm_state = vm_states.ACTIVE
instance.save()
break
except self._session.XenAPI.Failure:
LOG.exception(
_LE('Unable to migrate VM %(vm_ref)s '
'from %(host)s'), {
'vm_ref': vm_ref,
'host': host
})
instance.host = host
instance.vm_state = vm_states.ACTIVE
instance.save()
if vm_counter == migrations_counter:
return 'on_maintenance'
else:
raise exception.NoValidHost(reason='Unable to find suitable '
'host for VMs evacuation')
