root / snf-cyclades-app / synnefo / logic / backend_allocator.py @ f96f60fd
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1 | cc7c0f44 | Christos Stavrakakis | # Copyright 2011 GRNET S.A. All rights reserved.
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2 | cc7c0f44 | Christos Stavrakakis | #
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3 | cc7c0f44 | Christos Stavrakakis | # Redistribution and use in source and binary forms, with or without
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4 | cc7c0f44 | Christos Stavrakakis | # modification, are permitted provided that the following conditions
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5 | cc7c0f44 | Christos Stavrakakis | # are met:
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6 | cc7c0f44 | Christos Stavrakakis | #
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7 | cc7c0f44 | Christos Stavrakakis | # 1. Redistributions of source code must retain the above copyright
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8 | cc7c0f44 | Christos Stavrakakis | # notice, this list of conditions and the following disclaimer.
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9 | cc7c0f44 | Christos Stavrakakis | #
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10 | cc7c0f44 | Christos Stavrakakis | # 2. Redistributions in binary form must reproduce the above copyright
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11 | cc7c0f44 | Christos Stavrakakis | # notice, this list of conditions and the following disclaimer in the
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12 | cc7c0f44 | Christos Stavrakakis | # documentation and/or other materials provided with the distribution.
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13 | cc7c0f44 | Christos Stavrakakis | #
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14 | cc7c0f44 | Christos Stavrakakis | # THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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15 | cc7c0f44 | Christos Stavrakakis | # ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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16 | cc7c0f44 | Christos Stavrakakis | # IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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17 | cc7c0f44 | Christos Stavrakakis | # ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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18 | cc7c0f44 | Christos Stavrakakis | # FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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19 | cc7c0f44 | Christos Stavrakakis | # DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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20 | cc7c0f44 | Christos Stavrakakis | # OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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21 | cc7c0f44 | Christos Stavrakakis | # HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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22 | cc7c0f44 | Christos Stavrakakis | # LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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23 | cc7c0f44 | Christos Stavrakakis | # OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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24 | cc7c0f44 | Christos Stavrakakis | # SUCH DAMAGE.
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25 | cc7c0f44 | Christos Stavrakakis | #
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26 | cc7c0f44 | Christos Stavrakakis | # The views and conclusions contained in the software and documentation are
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27 | cc7c0f44 | Christos Stavrakakis | # those of the authors and should not be interpreted as representing official
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28 | cc7c0f44 | Christos Stavrakakis | # policies, either expressed or implied, of GRNET S.A.
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29 | cc7c0f44 | Christos Stavrakakis | |
30 | 47d1d754 | Christos Stavrakakis | import logging |
31 | cc7c0f44 | Christos Stavrakakis | import datetime |
32 | cc7c0f44 | Christos Stavrakakis | from django.utils import importlib |
33 | cc7c0f44 | Christos Stavrakakis | |
34 | cc7c0f44 | Christos Stavrakakis | from synnefo import settings |
35 | cc7c0f44 | Christos Stavrakakis | from synnefo.db.models import Backend |
36 | cc7c0f44 | Christos Stavrakakis | from synnefo.logic.backend import update_resources |
37 | f96f60fd | Christos Stavrakakis | from synnefo.api.util import backend_public_networks |
38 | cc7c0f44 | Christos Stavrakakis | |
39 | 47d1d754 | Christos Stavrakakis | log = logging.getLogger(__name__) |
40 | 47d1d754 | Christos Stavrakakis | |
41 | cc7c0f44 | Christos Stavrakakis | |
42 | cc7c0f44 | Christos Stavrakakis | class BackendAllocator(): |
43 | cc7c0f44 | Christos Stavrakakis | """Wrapper class for instance allocation.
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44 | cc7c0f44 | Christos Stavrakakis |
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45 | cc7c0f44 | Christos Stavrakakis | """
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46 | cc7c0f44 | Christos Stavrakakis | def __init__(self): |
47 | cc7c0f44 | Christos Stavrakakis | self.strategy_mod =\
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48 | cc7c0f44 | Christos Stavrakakis | importlib.import_module(settings.BACKEND_ALLOCATOR_MODULE) |
49 | cc7c0f44 | Christos Stavrakakis | |
50 | cc7c0f44 | Christos Stavrakakis | def allocate(self, flavor): |
51 | adc46059 | Christos Stavrakakis | """Allocate a vm of the specified flavor to a backend.
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52 | adc46059 | Christos Stavrakakis |
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53 | adc46059 | Christos Stavrakakis | Warning!!: An explicit commit is required after calling this function,
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54 | adc46059 | Christos Stavrakakis | in order to release the locks acquired by the get_available_backends
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55 | adc46059 | Christos Stavrakakis | function.
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56 | adc46059 | Christos Stavrakakis |
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57 | adc46059 | Christos Stavrakakis | """
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58 | cc7c0f44 | Christos Stavrakakis | # Get the size of the vm
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59 | cc7c0f44 | Christos Stavrakakis | disk = flavor_disk(flavor) |
60 | cc7c0f44 | Christos Stavrakakis | ram = flavor.ram |
61 | cc7c0f44 | Christos Stavrakakis | cpu = flavor.cpu |
62 | cc7c0f44 | Christos Stavrakakis | vm = {'ram': ram, 'disk': disk, 'cpu': cpu} |
63 | cc7c0f44 | Christos Stavrakakis | |
64 | 47d1d754 | Christos Stavrakakis | log.debug("Allocating VM: %r", vm)
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65 | 47d1d754 | Christos Stavrakakis | |
66 | cc7c0f44 | Christos Stavrakakis | # Refresh backends, if needed
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67 | cc7c0f44 | Christos Stavrakakis | refresh_backends_stats() |
68 | cc7c0f44 | Christos Stavrakakis | |
69 | cc7c0f44 | Christos Stavrakakis | # Get available backends
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70 | cc7c0f44 | Christos Stavrakakis | available_backends = get_available_backends() |
71 | cc7c0f44 | Christos Stavrakakis | |
72 | cc7c0f44 | Christos Stavrakakis | if not available_backends: |
73 | cc7c0f44 | Christos Stavrakakis | return None |
74 | cc7c0f44 | Christos Stavrakakis | |
75 | cc7c0f44 | Christos Stavrakakis | # Find the best backend to host the vm, based on the allocation
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76 | cc7c0f44 | Christos Stavrakakis | # strategy
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77 | 7fede91e | Christos Stavrakakis | backend = self.strategy_mod.allocate(available_backends, vm)
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78 | cc7c0f44 | Christos Stavrakakis | |
79 | 47d1d754 | Christos Stavrakakis | log.info("Allocated VM %r, in backend %s", vm, backend)
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80 | 47d1d754 | Christos Stavrakakis | |
81 | cc7c0f44 | Christos Stavrakakis | # Reduce the free resources of the selected backend by the size of
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82 | cc7c0f44 | Christos Stavrakakis | # the vm
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83 | cc7c0f44 | Christos Stavrakakis | reduce_backend_resources(backend, vm) |
84 | cc7c0f44 | Christos Stavrakakis | |
85 | cc7c0f44 | Christos Stavrakakis | return backend
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86 | cc7c0f44 | Christos Stavrakakis | |
87 | cc7c0f44 | Christos Stavrakakis | |
88 | cc7c0f44 | Christos Stavrakakis | def get_available_backends(): |
89 | cc7c0f44 | Christos Stavrakakis | """Get available backends from db.
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90 | cc7c0f44 | Christos Stavrakakis |
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91 | cc7c0f44 | Christos Stavrakakis | """
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92 | f96f60fd | Christos Stavrakakis | backends = list(Backend.objects.select_for_update().filter(drained=False, |
93 | f96f60fd | Christos Stavrakakis | offline=False))
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94 | f96f60fd | Christos Stavrakakis | return filter(lambda x: has_free_ip(x), backends) |
95 | f96f60fd | Christos Stavrakakis | |
96 | f96f60fd | Christos Stavrakakis | |
97 | f96f60fd | Christos Stavrakakis | def has_free_ip(backend): |
98 | f96f60fd | Christos Stavrakakis | """Find if Backend has any free public IP."""
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99 | f96f60fd | Christos Stavrakakis | for network in backend_public_networks(backend): |
100 | f96f60fd | Christos Stavrakakis | if not network.get_pool().empty(): |
101 | f96f60fd | Christos Stavrakakis | return True |
102 | f96f60fd | Christos Stavrakakis | return False |
103 | cc7c0f44 | Christos Stavrakakis | |
104 | cc7c0f44 | Christos Stavrakakis | |
105 | cc7c0f44 | Christos Stavrakakis | def flavor_disk(flavor): |
106 | cc7c0f44 | Christos Stavrakakis | """ Get flavor's 'real' disk size
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107 | cc7c0f44 | Christos Stavrakakis |
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108 | cc7c0f44 | Christos Stavrakakis | """
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109 | cc7c0f44 | Christos Stavrakakis | if flavor.disk_template == 'drbd': |
110 | cc7c0f44 | Christos Stavrakakis | return flavor.disk * 1024 * 2 |
111 | cc7c0f44 | Christos Stavrakakis | else:
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112 | cc7c0f44 | Christos Stavrakakis | return flavor.disk * 1024 |
113 | cc7c0f44 | Christos Stavrakakis | |
114 | cc7c0f44 | Christos Stavrakakis | |
115 | cc7c0f44 | Christos Stavrakakis | def reduce_backend_resources(backend, vm): |
116 | cc7c0f44 | Christos Stavrakakis | """ Conservatively update the resources of a backend.
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117 | cc7c0f44 | Christos Stavrakakis |
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118 | cc7c0f44 | Christos Stavrakakis | Reduce the free resources of the backend by the size of the of the vm that
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119 | cc7c0f44 | Christos Stavrakakis | will host. This is an underestimation of the backend capabilities.
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120 | cc7c0f44 | Christos Stavrakakis |
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121 | cc7c0f44 | Christos Stavrakakis | """
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122 | cc7c0f44 | Christos Stavrakakis | |
123 | cc7c0f44 | Christos Stavrakakis | new_mfree = backend.mfree - vm['ram']
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124 | cc7c0f44 | Christos Stavrakakis | new_dfree = backend.dfree - vm['disk']
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125 | cc7c0f44 | Christos Stavrakakis | backend.mfree = 0 if new_mfree < 0 else new_mfree |
126 | cc7c0f44 | Christos Stavrakakis | backend.dfree = 0 if new_dfree < 0 else new_dfree |
127 | cc7c0f44 | Christos Stavrakakis | backend.pinst_cnt += 1
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128 | cc7c0f44 | Christos Stavrakakis | |
129 | cc7c0f44 | Christos Stavrakakis | backend.save() |
130 | cc7c0f44 | Christos Stavrakakis | |
131 | cc7c0f44 | Christos Stavrakakis | |
132 | cc7c0f44 | Christos Stavrakakis | def refresh_backends_stats(): |
133 | cc7c0f44 | Christos Stavrakakis | """ Refresh the statistics of the backends.
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134 | cc7c0f44 | Christos Stavrakakis |
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135 | cc7c0f44 | Christos Stavrakakis | Set db backend state to the actual state of the backend, if
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136 | cc7c0f44 | Christos Stavrakakis | BACKEND_REFRESH_MIN time has passed.
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137 | cc7c0f44 | Christos Stavrakakis |
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138 | cc7c0f44 | Christos Stavrakakis | """
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139 | cc7c0f44 | Christos Stavrakakis | |
140 | cc7c0f44 | Christos Stavrakakis | now = datetime.datetime.now() |
141 | cc7c0f44 | Christos Stavrakakis | delta = datetime.timedelta(minutes=settings.BACKEND_REFRESH_MIN) |
142 | cc7c0f44 | Christos Stavrakakis | for b in Backend.objects.filter(drained=False, offline=False): |
143 | cc7c0f44 | Christos Stavrakakis | if now > b.updated + delta:
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144 | 47d1d754 | Christos Stavrakakis | log.debug("Updating resources of backend %r", b)
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145 | cc7c0f44 | Christos Stavrakakis | update_resources(b) |