Synnefo

from synnefo.logic.backend_allocator import BackendAllocator

from django.utils import importlib

    backend_allocator = BackendAllocator()

    backend = backend_allocator.allocate(flavor)

    if backend is None:

        raise Exception

    # We must save the VM instance now, so that it gets a valid

    # vm.backend_vm_id.

# This module implements the strategy for allocating a vm to a backend

BACKEND_ALLOCATOR_MODULE = "synnefo.logic.allocators.default_allocator"

# Refresh backend statistics timeout, in minutes, used in backend allocation

BACKEND_REFRESH_MIN = 15

# Copyright 2011 GRNET S.A. All rights reserved.

#

# Redistribution and use in source and binary forms, with or

# without modification, are permitted provided that the following

# conditions are met:

#

#   1. Redistributions of source code must retain the above

#      copyright notice, this list of conditions and the following

#      disclaimer.

#

#   2. Redistributions in binary form must reproduce the above

#      copyright notice, this list of conditions and the following

#      disclaimer in the documentation and/or other materials

#      provided with the distribution.

#

# THIS SOFTWARE IS PROVIDED BY GRNET S.A. ``AS IS'' AND ANY EXPRESS

# OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED

# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR

# PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL GRNET S.A OR

# CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT

# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF

# USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED

# AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT

# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN

# ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE

# POSSIBILITY OF SUCH DAMAGE.

#

# The views and conclusions contained in the software and

# documentation are those of the authors and should not be

# interpreted as representing official policies, either expressed

# or implied, of GRNET S.A.

from __future__ import division

def allocate(backends, vm):

    if len(backends) == 1:

        return backends.keys()[0]

    # Filter those that can not host the vm

    capable_backends = dict((k, v) for k, v in backends.iteritems()\

                            if vm_fits_in_backend(v, vm))

    # Since we are conservatively updating backend resources on each

    # allocation, a backend may actually be able to host a vm (despite

    # the state of the backend in db)

    if not capable_backends:

        capable_backends = backends

    # Compute the scores for each backend

    backend_scores = [(back_id, backend_score(back_resources, vm))\

                      for back_id, back_resources in \

                      capable_backends.iteritems()]

    # Pick out the best

    result = min(backend_scores, key=lambda (b_id, b_score): b_score)

    backend_id = result[0]

    return backend_id

def vm_fits_in_backend(backend, vm):

    return backend['dfree'] > vm['disk'] and backend['mfree'] > vm['ram']

def backend_score(backend, flavor):

    mratio = 1 - (backend['mfree'] / backend['mtotal'])

    dratio = 1 - (backend['dfree'] / backend['dtotal'])

    # cratio = (backend.pinst_cnt+1)/backend.ctotal

    return 0.5 * (mratio + dratio)

    return Backend.objects.filter(offline=False)

# Copyright 2011 GRNET S.A. All rights reserved.

#

# Redistribution and use in source and binary forms, with or without

# modification, are permitted provided that the following conditions

# are met:

#

#   1. Redistributions of source code must retain the above copyright

#      notice, this list of conditions and the following disclaimer.

#

#  2. Redistributions in binary form must reproduce the above copyright

#     notice, this list of conditions and the following disclaimer in the

#     documentation and/or other materials provided with the distribution.

#

# THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND

# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

# ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE

# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS

# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT

# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY

# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF

# SUCH DAMAGE.

#

# The views and conclusions contained in the software and documentation are

# those of the authors and should not be interpreted as representing official

# policies, either expressed or implied, of GRNET S.A.

import datetime

from django.utils import importlib

from synnefo import settings

from synnefo.db.models import Backend

from synnefo.logic.backend import update_resources

class BackendAllocator():

    """Wrapper class for instance allocation.

    """

    def __init__(self):

        self.strategy_mod =\

            importlib.import_module(settings.BACKEND_ALLOCATOR_MODULE)

    def allocate(self, flavor):

        # Get the size of the vm

        disk = flavor_disk(flavor)

        ram = flavor.ram

        cpu = flavor.cpu

        vm = {'ram': ram, 'disk': disk, 'cpu': cpu}

        # Refresh backends, if needed

        refresh_backends_stats()

        # Get available backends

        available_backends = get_available_backends()

        if not available_backends:

            return None

        # Find the best backend to host the vm, based on the allocation

        # strategy

        backend_id = self.strategy_mod.allocate(available_backends, vm)

        backend = Backend.objects.get(id=backend_id)

        # Reduce the free resources of the selected backend by the size of

        # the vm

        reduce_backend_resources(backend, vm)

        return backend

def get_available_backends():

    """Get available backends from db.

    """

    attrs = ['mfree', 'mtotal', 'dfree', 'dtotal', 'pinst_cnt', 'ctotal']

    backends = {}

    for b in Backend.objects.filter(drained=False, offline=False):

        backend = {}

        for a in attrs:

            backend[a] = getattr(b, a)

        backends[b.id] = backend

    return backends

def flavor_disk(flavor):

    """ Get flavor's 'real' disk size

    """

    if flavor.disk_template == 'drbd':

        return flavor.disk * 1024 * 2

    else:

        return flavor.disk * 1024

def reduce_backend_resources(backend, vm):

    """ Conservatively update the resources of a backend.

    Reduce the free resources of the backend by the size of the of the vm that

    will host. This is an underestimation of the backend capabilities.

    """

    new_mfree = backend.mfree - vm['ram']

    new_dfree = backend.dfree - vm['disk']

    backend.mfree = 0 if new_mfree < 0 else new_mfree

    backend.dfree = 0 if new_dfree < 0 else new_dfree

    backend.pinst_cnt += 1

    backend.save()

def refresh_backends_stats():

    """ Refresh the statistics of the backends.

    Set db backend state to the actual state of the backend, if

    BACKEND_REFRESH_MIN time has passed.

    """

    now = datetime.datetime.now()

    delta = datetime.timedelta(minutes=settings.BACKEND_REFRESH_MIN)

    for b in Backend.objects.filter(drained=False, offline=False):

        if now > b.updated + delta:

            update_resources(b)

# Copyright 2011-2012 GRNET S.A. All rights reserved.

#

# Redistribution and use in source and binary forms, with or without

# modification, are permitted provided that the following conditions

# are met:

#

#   1. Redistributions of source code must retain the above copyright

#      notice, this list of conditions and the following disclaimer.

#

#  2. Redistributions in binary form must reproduce the above copyright

#     notice, this list of conditions and the following disclaimer in the

#     documentation and/or other materials provided with the distribution.

#

# THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND

# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

# ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE

# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS

# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT

# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY

# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF

# SUCH DAMAGE.

#

# The views and conclusions contained in the software and documentation are

# those of the authors and should not be interpreted as representing official

# policies, either expressed or implied, of GRNET S.A.

#

from optparse import make_option

from django.core.management.base import BaseCommand, CommandError

from synnefo import settings

import datetime

from synnefo.db.models import Backend

from synnefo.logic.backend import update_resources

class Command(BaseCommand):

    can_import_settings = True

    help = "Update backend statistics, which are used for instance allocation."

    output_transaction = True  # The management command runs inside

                               # an SQL transaction

    option_list = BaseCommand.option_list + (

        make_option('--backend_id', dest='backend_id',

                   help="Update statistics of only this backend"),

        make_option('--older_than', dest='older_than', metavar="MINUTES",

                   help="Update only backends that have not been updated for\

                   MINUTES. Set to 0 to force update.")

        )

    def handle(self, **options):

        if options['backend_id']:

            try:

                backend_id = int(options['backend_id'])

                backends = [Backend.objects.get(id=backend_id)]

            except ValueError:

                raise CommandError("Wrong backend ID")

            except Backend.DoesNotExist:

                raise CommandError("Backend not found in DB")

        else:

            # XXX:filter drained ?

            backends = Backend.objects.all()

        now = datetime.datetime.now()

        if options['older_than'] is not None:

            minutes = int(options['older_than'])

        else:

            minutes = settings.BACKEND_REFRESH_MIN

        delta = datetime.timedelta(minutes=minutes)

        for b in backends:

            if now > b.updated + delta:

                update_resources(b)

                print 'Successfully updated backend with id: %d' % b.id

            else:

                print 'Backend %d does not need update' % b.id