6ded00b034
In preparation for adding resize support to resource tracker: * Claim class has been factored out of resource tracker. * Broke out claim testing logic for easier re-use This patch is pre-work to ease adding resize claims to resource tracker: bug 1065267 Change-Id: Ib0b856376417f140dc9ed114913f47a8a790b8a2
326 lines
13 KiB
Python
326 lines
13 KiB
Python
# Copyright (c) 2012 OpenStack, LLC.
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# All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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"""
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Track resources like memory and disk for a compute host. Provides the
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scheduler with useful information about availability through the ComputeNode
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model.
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"""
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from nova.compute import claims
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from nova.compute import vm_states
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from nova import context
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from nova import db
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from nova import exception
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from nova import flags
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from nova import notifications
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from nova.openstack.common import cfg
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from nova.openstack.common import importutils
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from nova.openstack.common import lockutils
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from nova.openstack.common import log as logging
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from nova import utils
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resource_tracker_opts = [
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cfg.IntOpt('reserved_host_disk_mb', default=0,
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help='Amount of disk in MB to reserve for the host'),
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cfg.IntOpt('reserved_host_memory_mb', default=512,
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help='Amount of memory in MB to reserve for the host'),
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cfg.StrOpt('compute_stats_class',
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default='nova.compute.stats.Stats',
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help='Class that will manage stats for the local compute host')
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]
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FLAGS = flags.FLAGS
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FLAGS.register_opts(resource_tracker_opts)
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LOG = logging.getLogger(__name__)
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COMPUTE_RESOURCE_SEMAPHORE = claims.COMPUTE_RESOURCE_SEMAPHORE
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class ResourceTracker(object):
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"""Compute helper class for keeping track of resource usage as instances
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are built and destroyed.
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"""
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def __init__(self, host, driver):
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self.host = host
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self.driver = driver
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self.compute_node = None
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self.stats = importutils.import_object(FLAGS.compute_stats_class)
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self.tracked_instances = {}
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@lockutils.synchronized(COMPUTE_RESOURCE_SEMAPHORE, 'nova-')
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def instance_claim(self, context, instance_ref, limits=None):
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"""Indicate that some resources are needed for an upcoming compute
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instance build operation.
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This should be called before the compute node is about to perform
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an instance build operation that will consume additional resources.
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:param context: security context
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:param instance_ref: instance to reserve resources for
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:param limits: Dict of oversubscription limits for memory, disk,
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and CPUs.
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:returns: A Claim ticket representing the reserved resources. It can
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be used to revert the resource usage if an error occurs
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during the instance build.
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"""
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if self.disabled:
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# compute_driver doesn't support resource tracking, just
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# set the 'host' field and continue the build:
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instance_ref = self._set_instance_host(context,
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instance_ref['uuid'])
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return claims.NopClaim()
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# sanity check:
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if instance_ref['host']:
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LOG.warning(_("Host field should be not be set on the instance "
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"until resources have been claimed."),
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instance=instance_ref)
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claim = claims.Claim(instance_ref, self)
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if claim.test(self.compute_node, limits):
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instance_ref = self._set_instance_host(context,
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instance_ref['uuid'])
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# Mark resources in-use and update stats
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self._update_usage_from_instance(self.compute_node, instance_ref)
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# persist changes to the compute node:
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self._update(context, self.compute_node)
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return claim
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else:
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raise exception.ComputeResourcesUnavailable()
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def _set_instance_host(self, context, instance_uuid):
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"""Tag the instance as belonging to this host. This should be done
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while the COMPUTE_RESOURCES_SEMPAHORE is being held so the resource
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claim will not be lost if the audit process starts.
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"""
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values = {'host': self.host, 'launched_on': self.host}
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(old_ref, instance_ref) = db.instance_update_and_get_original(context,
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instance_uuid, values)
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notifications.send_update(context, old_ref, instance_ref)
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return instance_ref
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def abort_instance_claim(self, instance):
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"""Remove usage from the given instance"""
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# flag the instance as deleted to revert the resource usage
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# and associated stats:
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instance['vm_state'] = vm_states.DELETED
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self._update_usage_from_instance(self.compute_node, instance)
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ctxt = context.get_admin_context()
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self._update(ctxt, self.compute_node)
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@lockutils.synchronized(COMPUTE_RESOURCE_SEMAPHORE, 'nova-')
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def update_usage(self, context, instance):
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"""Update the resource usage and stats after a change in an
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instance
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"""
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if self.disabled:
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return
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# don't update usage for this instance unless it submitted a resource
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# claim first:
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uuid = instance['uuid']
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if uuid in self.tracked_instances:
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self._update_usage_from_instance(self.compute_node, instance)
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self._update(context.elevated(), self.compute_node)
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@property
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def disabled(self):
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return self.compute_node is None
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@lockutils.synchronized(COMPUTE_RESOURCE_SEMAPHORE, 'nova-')
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def update_available_resource(self, context):
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"""Override in-memory calculations of compute node resource usage based
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on data audited from the hypervisor layer.
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Add in resource claims in progress to account for operations that have
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declared a need for resources, but not necessarily retrieved them from
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the hypervisor layer yet.
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"""
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resources = self.driver.get_available_resource()
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if not resources:
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# The virt driver does not support this function
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LOG.audit(_("Virt driver does not support "
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"'get_available_resource' Compute tracking is disabled."))
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self.compute_node = None
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return
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self._verify_resources(resources)
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self._report_hypervisor_resource_view(resources)
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# Grab all instances assigned to this host:
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instances = db.instance_get_all_by_host(context, self.host)
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# Now calculate usage based on instance utilization:
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self._update_usage_from_instances(resources, instances)
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self._report_final_resource_view(resources)
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self._sync_compute_node(context, resources)
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def _sync_compute_node(self, context, resources):
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"""Create or update the compute node DB record"""
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if not self.compute_node:
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# we need a copy of the ComputeNode record:
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service = self._get_service(context)
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if not service:
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# no service record, disable resource
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return
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compute_node_ref = service['compute_node']
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if compute_node_ref:
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self.compute_node = compute_node_ref[0]
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if not self.compute_node:
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# Need to create the ComputeNode record:
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resources['service_id'] = service['id']
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self._create(context, resources)
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LOG.info(_('Compute_service record created for %s ') % self.host)
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else:
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# just update the record:
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self._update(context, resources, prune_stats=True)
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LOG.info(_('Compute_service record updated for %s ') % self.host)
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def _create(self, context, values):
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"""Create the compute node in the DB"""
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# initialize load stats from existing instances:
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compute_node = db.compute_node_create(context, values)
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self.compute_node = dict(compute_node)
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def _get_service(self, context):
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try:
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return db.service_get_all_compute_by_host(context,
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self.host)[0]
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except exception.NotFound:
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LOG.warn(_("No service record for host %s"), self.host)
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def _report_hypervisor_resource_view(self, resources):
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"""Log the hypervisor's view of free memory in and free disk.
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This is just a snapshot of resource usage recorded by the
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virt driver.
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"""
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free_ram_mb = resources['memory_mb'] - resources['memory_mb_used']
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free_disk_gb = resources['local_gb'] - resources['local_gb_used']
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LOG.debug(_("Hypervisor: free ram (MB): %s") % free_ram_mb)
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LOG.debug(_("Hypervisor: free disk (GB): %s") % free_disk_gb)
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vcpus = resources['vcpus']
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if vcpus:
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free_vcpus = vcpus - resources['vcpus_used']
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LOG.debug(_("Hypervisor: free VCPUs: %s") % free_vcpus)
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else:
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LOG.debug(_("Hypervisor: VCPU information unavailable"))
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def _report_final_resource_view(self, resources):
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"""Report final calculate of free memory and free disk including
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instance calculations and in-progress resource claims. These
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values will be exposed via the compute node table to the scheduler.
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"""
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LOG.audit(_("Free ram (MB): %s") % resources['free_ram_mb'])
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LOG.audit(_("Free disk (GB): %s") % resources['free_disk_gb'])
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vcpus = resources['vcpus']
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if vcpus:
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free_vcpus = vcpus - resources['vcpus_used']
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LOG.audit(_("Free VCPUS: %s") % free_vcpus)
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else:
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LOG.audit(_("Free VCPU information unavailable"))
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def _update(self, context, values, prune_stats=False):
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"""Persist the compute node updates to the DB"""
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compute_node = db.compute_node_update(context,
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self.compute_node['id'], values, prune_stats)
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self.compute_node = dict(compute_node)
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def _update_usage_from_instance(self, resources, instance):
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"""Update usage for a single instance."""
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uuid = instance['uuid']
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is_new_instance = uuid not in self.tracked_instances
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is_deleted_instance = instance['vm_state'] == vm_states.DELETED
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if is_new_instance:
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self.tracked_instances[uuid] = 1
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sign = 1
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if is_deleted_instance:
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self.tracked_instances.pop(uuid)
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sign = -1
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self.stats.update_stats_for_instance(instance)
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# if it's a new or deleted instance:
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if is_new_instance or is_deleted_instance:
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# new instance, update compute node resource usage:
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resources['memory_mb_used'] += sign * instance['memory_mb']
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resources['local_gb_used'] += sign * instance['root_gb']
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resources['local_gb_used'] += sign * instance['ephemeral_gb']
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# free ram and disk may be negative, depending on policy:
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resources['free_ram_mb'] = (resources['memory_mb'] -
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resources['memory_mb_used'])
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resources['free_disk_gb'] = (resources['local_gb'] -
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resources['local_gb_used'])
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resources['running_vms'] = self.stats.num_instances
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resources['vcpus_used'] = self.stats.num_vcpus_used
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resources['current_workload'] = self.stats.calculate_workload()
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resources['stats'] = self.stats
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def _update_usage_from_instances(self, resources, instances):
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"""Calculate resource usage based on instance utilization. This is
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different than the hypervisor's view as it will account for all
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instances assigned to the local compute host, even if they are not
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currently powered on.
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"""
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self.tracked_instances.clear()
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# purge old stats
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self.stats.clear()
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# set some intiial values, reserve room for host/hypervisor:
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resources['local_gb_used'] = FLAGS.reserved_host_disk_mb / 1024
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resources['memory_mb_used'] = FLAGS.reserved_host_memory_mb
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resources['vcpus_used'] = 0
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resources['free_ram_mb'] = (resources['memory_mb'] -
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resources['memory_mb_used'])
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resources['free_disk_gb'] = (resources['local_gb'] -
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resources['local_gb_used'])
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resources['current_workload'] = 0
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resources['running_vms'] = 0
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for instance in instances:
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self._update_usage_from_instance(resources, instance)
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def _verify_resources(self, resources):
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resource_keys = ["vcpus", "memory_mb", "local_gb", "cpu_info",
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"vcpus_used", "memory_mb_used", "local_gb_used"]
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missing_keys = [k for k in resource_keys if k not in resources]
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if missing_keys:
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reason = _("Missing keys: %s") % missing_keys
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raise exception.InvalidInput(reason=reason)
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