2bb514f2d7
When retrieving a vacant L3 agent binding index, if "is_manual_scheduling" is set, the method "get_vacant_binding_index" should always return a valid binding index. If the existing binding indexes are sequentially aligned, the method will return a new one on top; if there is a gap in the binding indexes list, the first free index will be returned. Closes-Bug: #1884906 Change-Id: I0a89bca0734d3e735fb357e488f85589e81d709f
123 lines
4.9 KiB
Python
123 lines
4.9 KiB
Python
# Copyright (c) 2015 OpenStack Foundation.
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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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import abc
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from operator import attrgetter
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import random
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from oslo_log import log as logging
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LOG = logging.getLogger(__name__)
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class BaseScheduler(object, metaclass=abc.ABCMeta):
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"""The base scheduler (agnostic to resource type).
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Child classes of BaseScheduler must define the
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self.resource_filter to filter agents of
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particular type.
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"""
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resource_filter = None
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@abc.abstractmethod
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def select(self, plugin, context, resource_hostable_agents,
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resource_hosted_agents, num_agents_needed):
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"""Return a subset of agents based on the specific scheduling logic."""
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def schedule(self, plugin, context, resource):
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"""Select and bind agents to a given resource."""
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if not self.resource_filter:
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return
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# filter the agents that can host the resource
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filtered_agents_dict = self.resource_filter.filter_agents(
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plugin, context, resource)
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num_agents = filtered_agents_dict['n_agents']
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hostable_agents = filtered_agents_dict['hostable_agents']
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hosted_agents = filtered_agents_dict['hosted_agents']
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chosen_agents = self.select(plugin, context, hostable_agents,
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hosted_agents, num_agents)
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# bind the resource to the agents
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force_scheduling = bool(resource.get('candidate_hosts'))
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self.resource_filter.bind(
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context, chosen_agents, resource['id'], force_scheduling)
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debug_data = ['(%s, %s, %s)' %
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(agent['agent_type'], agent['host'], resource['id'])
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for agent in chosen_agents]
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LOG.debug('Resources bound (agent type, host, resource id): %s',
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', '.join(debug_data))
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return chosen_agents
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class BaseChanceScheduler(BaseScheduler):
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"""Choose agents randomly."""
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def __init__(self, resource_filter):
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self.resource_filter = resource_filter
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def select(self, plugin, context, resource_hostable_agents,
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resource_hosted_agents, num_agents_needed):
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chosen_agents = random.sample(resource_hostable_agents,
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num_agents_needed)
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return chosen_agents
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class BaseWeightScheduler(BaseScheduler):
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"""Choose agents based on load."""
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def __init__(self, resource_filter):
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self.resource_filter = resource_filter
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def select(self, plugin, context, resource_hostable_agents,
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resource_hosted_agents, num_agents_needed):
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chosen_agents = sorted(resource_hostable_agents,
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key=attrgetter('load'))[0:num_agents_needed]
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return chosen_agents
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def get_vacant_binding_index(num_agents, bindings, lowest_binding_index,
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force_scheduling=False):
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"""Return a vacant binding_index to use and whether or not it exists.
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This method can be used with DHCP and L3 agent schedulers. It will return
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the lowest vacant index for one of those agents.
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:param num_agents: (int) number of agents (DHCP, L3) already scheduled
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:param bindings: (NetworkDhcpAgentBinding, RouterL3AgentBinding) agent
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binding object, must have "binding_index" field.
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:param lowest_binding_index: (int) lowest index number to be scheduled.
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:param force_scheduling: (optional)(boolean) if enabled, the method will
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always return an index, even if this number
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exceeds the maximum configured number of agents.
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"""
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binding_indices = [b.binding_index for b in bindings]
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all_indices = set(range(lowest_binding_index, num_agents + 1))
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open_slots = sorted(list(all_indices - set(binding_indices)))
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if open_slots:
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return open_slots[0]
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if not force_scheduling:
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return -1
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# Last chance: if this is a manual scheduling, we're gonna allow
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# creation of a binding_index even if it will exceed
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# dhcp_agents_per_network.
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if max(binding_indices) == len(binding_indices):
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return max(binding_indices) + 1
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else:
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# Find binding index set gaps and return first free one.
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all_indices = set(range(lowest_binding_index,
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max(binding_indices) + 1))
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open_slots = sorted(list(all_indices - set(binding_indices)))
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return open_slots[0]
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