gantt/nova/scheduler/host_manager.py
Brian Elliott a187d8885e Fix bugs in resource tracker and cleanup
Fixes bugs in resource tracker:
* Handle disk oversubscription
* Handle suspended/powered off instances

The usage model is changed to the old style that is
based on actual instance usage on a compute host.
(Not the current point in time of the hypervisor's
 reported host stats)

There is now a 'limits' filter property that can be passed from
the scheduler to the compute node to indicate that
oversubscription of resources is desired:

The 'limits' filter property is a dict with the following possible
keys:

* memory_mb - Specifies the memory ceiling for the compute node.
* disk_gb - Specifies the disk space ceiling for the compute node.
* vcpu - Specifies the max number of vcpus for the compute node.

There is also some general cleanup and additional unit tests in
an attempt to simplify down this function.

bug 1048842
bug 1052157

Change-Id: I6ee851b8c03234a78a64d9f5c494dfc7059cdda4
2012-09-20 05:11:10 +00:00

274 lines
9.8 KiB
Python

# Copyright (c) 2011 OpenStack, LLC.
# All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
"""
Manage hosts in the current zone.
"""
import UserDict
from nova import db
from nova import exception
from nova import flags
from nova.openstack.common import cfg
from nova.openstack.common import log as logging
from nova.openstack.common import timeutils
from nova.scheduler import filters
host_manager_opts = [
cfg.MultiStrOpt('scheduler_available_filters',
default=['nova.scheduler.filters.standard_filters'],
help='Filter classes available to the scheduler which may '
'be specified more than once. An entry of '
'"nova.scheduler.filters.standard_filters" '
'maps to all filters included with nova.'),
cfg.ListOpt('scheduler_default_filters',
default=[
'RetryFilter',
'AvailabilityZoneFilter',
'RamFilter',
'ComputeFilter',
'ComputeCapabilitiesFilter',
'ImagePropertiesFilter'
],
help='Which filter class names to use for filtering hosts '
'when not specified in the request.'),
]
FLAGS = flags.FLAGS
FLAGS.register_opts(host_manager_opts)
LOG = logging.getLogger(__name__)
class ReadOnlyDict(UserDict.IterableUserDict):
"""A read-only dict."""
def __init__(self, source=None):
self.data = {}
self.update(source)
def __setitem__(self, key, item):
raise TypeError
def __delitem__(self, key):
raise TypeError
def clear(self):
raise TypeError
def pop(self, key, *args):
raise TypeError
def popitem(self):
raise TypeError
def update(self, source=None):
if source is None:
return
elif isinstance(source, UserDict.UserDict):
self.data = source.data
elif isinstance(source, type({})):
self.data = source
else:
raise TypeError
class HostState(object):
"""Mutable and immutable information tracked for a host.
This is an attempt to remove the ad-hoc data structures
previously used and lock down access.
"""
def __init__(self, host, topic, capabilities=None, service=None):
self.host = host
self.topic = topic
# Read-only capability dicts
if capabilities is None:
capabilities = {}
self.capabilities = ReadOnlyDict(capabilities.get(topic, None))
if service is None:
service = {}
self.service = ReadOnlyDict(service)
# Mutable available resources.
# These will change as resources are virtually "consumed".
self.total_usable_disk_gb = 0
self.disk_mb_used = 0
self.free_ram_mb = 0
self.free_disk_mb = 0
self.vcpus_total = 0
self.vcpus_used = 0
# Resource oversubscription values for the compute host:
self.limits = {}
def update_from_compute_node(self, compute):
"""Update information about a host from its compute_node info."""
all_ram_mb = compute['memory_mb']
# Assume virtual size is all consumed by instances if use qcow2 disk.
least = compute.get('disk_available_least')
free_disk_mb = least if least is not None else compute['free_disk_gb']
free_disk_mb *= 1024
self.disk_mb_used = compute['local_gb_used'] * 1024
#NOTE(jogo) free_ram_mb can be negative
self.free_ram_mb = compute['free_ram_mb']
self.total_usable_ram_mb = all_ram_mb
self.total_usable_disk_gb = compute['local_gb']
self.free_disk_mb = free_disk_mb
self.vcpus_total = compute['vcpus']
self.vcpus_used = compute['vcpus_used']
def consume_from_instance(self, instance):
"""Incrementally update host state from an instance"""
disk_mb = (instance['root_gb'] + instance['ephemeral_gb']) * 1024
ram_mb = instance['memory_mb']
vcpus = instance['vcpus']
self.free_ram_mb -= ram_mb
self.free_disk_mb -= disk_mb
self.vcpus_used += vcpus
def passes_filters(self, filter_fns, filter_properties):
"""Return whether or not this host passes filters."""
if self.host in filter_properties.get('ignore_hosts', []):
LOG.debug(_('Host filter fails for ignored host %(host)s'),
{'host': self.host})
return False
force_hosts = filter_properties.get('force_hosts', [])
if force_hosts:
if not self.host in force_hosts:
LOG.debug(_('Host filter fails for non-forced host %(host)s'),
{'host': self.host})
return self.host in force_hosts
for filter_fn in filter_fns:
if not filter_fn(self, filter_properties):
LOG.debug(_('Host filter function %(func)s failed for '
'%(host)s'),
{'func': repr(filter_fn),
'host': self.host})
return False
LOG.debug(_('Host filter passes for %(host)s'), {'host': self.host})
return True
def __repr__(self):
return ("host '%s': free_ram_mb:%s free_disk_mb:%s" %
(self.host, self.free_ram_mb, self.free_disk_mb))
class HostManager(object):
"""Base HostManager class."""
# Can be overridden in a subclass
host_state_cls = HostState
def __init__(self):
self.service_states = {} # { <host> : { <service> : { cap k : v }}}
self.filter_classes = filters.get_filter_classes(
FLAGS.scheduler_available_filters)
def _choose_host_filters(self, filters):
"""Since the caller may specify which filters to use we need
to have an authoritative list of what is permissible. This
function checks the filter names against a predefined set
of acceptable filters.
"""
if filters is None:
filters = FLAGS.scheduler_default_filters
if not isinstance(filters, (list, tuple)):
filters = [filters]
good_filters = []
bad_filters = []
for filter_name in filters:
found_class = False
for cls in self.filter_classes:
if cls.__name__ == filter_name:
found_class = True
filter_instance = cls()
# Get the filter function
filter_func = getattr(filter_instance,
'host_passes', None)
if filter_func:
good_filters.append(filter_func)
break
if not found_class:
bad_filters.append(filter_name)
if bad_filters:
msg = ", ".join(bad_filters)
raise exception.SchedulerHostFilterNotFound(filter_name=msg)
return good_filters
def filter_hosts(self, hosts, filter_properties, filters=None):
"""Filter hosts and return only ones passing all filters"""
filtered_hosts = []
filter_fns = self._choose_host_filters(filters)
for host in hosts:
if host.passes_filters(filter_fns, filter_properties):
filtered_hosts.append(host)
return filtered_hosts
def update_service_capabilities(self, service_name, host, capabilities):
"""Update the per-service capabilities based on this notification."""
LOG.debug(_("Received %(service_name)s service update from "
"%(host)s.") % locals())
service_caps = self.service_states.get(host, {})
# Copy the capabilities, so we don't modify the original dict
capab_copy = dict(capabilities)
capab_copy["timestamp"] = timeutils.utcnow() # Reported time
service_caps[service_name] = capab_copy
self.service_states[host] = service_caps
def get_all_host_states(self, context, topic):
"""Returns a dict of all the hosts the HostManager
knows about. Also, each of the consumable resources in HostState
are pre-populated and adjusted based on data in the db.
For example:
{'192.168.1.100': HostState(), ...}
Note: this can be very slow with a lot of instances.
InstanceType table isn't required since a copy is stored
with the instance (in case the InstanceType changed since the
instance was created)."""
if topic != 'compute':
raise NotImplementedError(_(
"host_manager only implemented for 'compute'"))
host_state_map = {}
# Get resource usage across the available compute nodes:
compute_nodes = db.compute_node_get_all(context)
for compute in compute_nodes:
service = compute['service']
if not service:
LOG.warn(_("No service for compute ID %s") % compute['id'])
continue
host = service['host']
capabilities = self.service_states.get(host, None)
host_state = self.host_state_cls(host, topic,
capabilities=capabilities,
service=dict(service.iteritems()))
host_state.update_from_compute_node(compute)
host_state_map[host] = host_state
return host_state_map