2012-10-02 16:18:22 +10:00

132 lines
4.7 KiB
Python

# Copyright 2012 Anton Beloglazov
#
# 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.
""" Bin Packing based VM placement algorithms.
"""
from contracts import contract
from neat.contracts_extra import *
import logging
log = logging.getLogger(__name__)
@contract
def best_fit_decreasing_factory(time_step, migration_time, params):
""" Creates the Best Fit Decreasing (BFD) heuristic for VM placement.
:param time_step: The length of the simulation time step in seconds.
:type time_step: int,>=0
:param migration_time: The VM migration time in time seconds.
:type migration_time: float,>=0
:param params: A dictionary containing the algorithm's parameters.
:type params: dict(str: *)
:return: A function implementing the BFD algorithm.
:rtype: function
"""
return lambda hosts_cpu_usage, hosts_cpu_total, \
hosts_ram_usage, hosts_ram_total, \
inactive_hosts_cpu, inactive_hosts_ram, \
vms_cpu, vms_ram, state=None: \
(best_fit_decreasing(get_available_resources(
params['cpu_threshold'],
hosts_cpu_usage, hosts_cpu_total),
get_available_resources(params['ram_threshold'],
hosts_ram_usage, hosts_ram_total),
inactive_hosts_cpu, inactive_hosts_ram,
vms_cpu, vms_ram), {})
@contract
def get_available_resources(threshold, usage, total):
""" Get a map of the available resource capacity.
:param threshold: A threshold on the maximum allowed resource usage.
:type threshold: float,>=0,<=1
:param usage: A map of hosts to the resource usage.
:type usage: dict(str: number)
:param total: A map of hosts to the total resource capacity.
:type total: dict(str: number)
:return: A map of hosts to the available resource capacity.
:rtype: dict(str: int)
"""
return dict((host, int(threshold * total[host] - resource))
for host, resource in usage.items())
@contract
def best_fit_decreasing(hosts_cpu, hosts_ram,
inactive_hosts_cpu, inactive_hosts_ram,
vms_cpu, vms_ram):
""" The Best Fit Decreasing (BFD) heuristic for placing VMs on hosts.
:param hosts_cpu: A map of host names and their available CPU in MHz.
:type hosts_cpu: dict(str: int)
:param hosts_ram: A map of host names and their available RAM in MB.
:type hosts_ram: dict(str: int)
:param inactive_hosts_cpu: A map of inactive hosts and available CPU MHz.
:type inactive_hosts_cpu: dict(str: int)
:param inactive_hosts_ram: A map of inactive hosts and available RAM MB.
:type inactive_hosts_ram: dict(str: int)
:param vms_cpu: A map of VM UUID and their CPU utilization in MHz.
:type vms_cpu: dict(str: int)
:param vms_ram: A map of VM UUID and their RAM usage in MB.
:type vms_ram: dict(str: int)
:return: A map of VM UUIDs to host names, or {} if cannot be solved.
:rtype: dict(str: str)
"""
vms = sorted(((v, vms_ram[k], k)
for k, v in vms_cpu.items()), reverse=True)
hosts = sorted(((v, hosts_ram[k], k)
for k, v in hosts_cpu.items()))
inactive_hosts = sorted(((v, inactive_hosts_ram[k], k)
for k, v in inactive_hosts_cpu.items()))
mapping = {}
for vm_cpu, vm_ram, vm_uuid in vms:
mapped = False
while not mapped:
for _, _, host in hosts:
if hosts_cpu[host] >= vm_cpu and \
hosts_ram[host] >= vm_ram:
mapping[vm_uuid] = host
hosts_cpu[host] -= vm_cpu
hosts_ram[host] -= vm_ram
mapped = True
break
else:
if inactive_hosts:
activated_host = inactive_hosts.pop(0)
hosts.append(activated_host)
hosts = sorted(hosts)
hosts_cpu[activated_host[2]] = activated_host[0]
hosts_ram[activated_host[2]] = activated_host[1]
else:
break
if len(vms) == len(mapping):
return mapping
return {}