root / snf-cyclades-app / synnefo / logic / allocators / default_allocator.py @ a633e247
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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
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4 | cc7c0f44 | Christos Stavrakakis | # without modification, are permitted provided that the following
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5 | cc7c0f44 | Christos Stavrakakis | # conditions 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
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8 | cc7c0f44 | Christos Stavrakakis | # copyright notice, this list of conditions and the following
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9 | cc7c0f44 | Christos Stavrakakis | # disclaimer.
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10 | cc7c0f44 | Christos Stavrakakis | #
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11 | cc7c0f44 | Christos Stavrakakis | # 2. Redistributions in binary form must reproduce the above
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12 | cc7c0f44 | Christos Stavrakakis | # copyright notice, this list of conditions and the following
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13 | cc7c0f44 | Christos Stavrakakis | # disclaimer in the documentation and/or other materials
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14 | cc7c0f44 | Christos Stavrakakis | # provided with the distribution.
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15 | cc7c0f44 | Christos Stavrakakis | #
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16 | cc7c0f44 | Christos Stavrakakis | # THIS SOFTWARE IS PROVIDED BY GRNET S.A. ``AS IS'' AND ANY EXPRESS
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17 | cc7c0f44 | Christos Stavrakakis | # OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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18 | cc7c0f44 | Christos Stavrakakis | # WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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19 | cc7c0f44 | Christos Stavrakakis | # PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL GRNET S.A OR
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20 | cc7c0f44 | Christos Stavrakakis | # CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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21 | cc7c0f44 | Christos Stavrakakis | # SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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22 | cc7c0f44 | Christos Stavrakakis | # LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
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23 | cc7c0f44 | Christos Stavrakakis | # USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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24 | cc7c0f44 | Christos Stavrakakis | # AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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25 | cc7c0f44 | Christos Stavrakakis | # LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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26 | cc7c0f44 | Christos Stavrakakis | # ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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27 | cc7c0f44 | Christos Stavrakakis | # POSSIBILITY OF SUCH DAMAGE.
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28 | cc7c0f44 | Christos Stavrakakis | #
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29 | cc7c0f44 | Christos Stavrakakis | # The views and conclusions contained in the software and
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30 | cc7c0f44 | Christos Stavrakakis | # documentation are those of the authors and should not be
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31 | cc7c0f44 | Christos Stavrakakis | # interpreted as representing official policies, either expressed
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32 | cc7c0f44 | Christos Stavrakakis | # or implied, of GRNET S.A.
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33 | cc7c0f44 | Christos Stavrakakis | |
34 | cc7c0f44 | Christos Stavrakakis | from __future__ import division |
35 | 47d1d754 | Christos Stavrakakis | import logging |
36 | f96f60fd | Christos Stavrakakis | |
37 | cc7c0f44 | Christos Stavrakakis | |
38 | 47d1d754 | Christos Stavrakakis | log = logging.getLogger(__name__) |
39 | 47d1d754 | Christos Stavrakakis | |
40 | cc7c0f44 | Christos Stavrakakis | |
41 | cc7c0f44 | Christos Stavrakakis | def allocate(backends, vm): |
42 | cc7c0f44 | Christos Stavrakakis | if len(backends) == 1: |
43 | 7fede91e | Christos Stavrakakis | return backends[0] |
44 | cc7c0f44 | Christos Stavrakakis | |
45 | cc7c0f44 | Christos Stavrakakis | # Filter those that can not host the vm
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46 | 7fede91e | Christos Stavrakakis | capable_backends = [backend for backend in backends |
47 | 7fede91e | Christos Stavrakakis | if vm_fits_in_backend(backend, vm)]
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48 | cc7c0f44 | Christos Stavrakakis | |
49 | 47d1d754 | Christos Stavrakakis | log.debug("Capable backends for VM %s: %s", vm, capable_backends)
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50 | 47d1d754 | Christos Stavrakakis | |
51 | cc7c0f44 | Christos Stavrakakis | # Since we are conservatively updating backend resources on each
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52 | cc7c0f44 | Christos Stavrakakis | # allocation, a backend may actually be able to host a vm (despite
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53 | cc7c0f44 | Christos Stavrakakis | # the state of the backend in db)
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54 | cc7c0f44 | Christos Stavrakakis | if not capable_backends: |
55 | cc7c0f44 | Christos Stavrakakis | capable_backends = backends |
56 | cc7c0f44 | Christos Stavrakakis | |
57 | cc7c0f44 | Christos Stavrakakis | # Compute the scores for each backend
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58 | 7fede91e | Christos Stavrakakis | backend_scores = [(backend, backend_score(backend, vm)) |
59 | 7fede91e | Christos Stavrakakis | for backend in capable_backends] |
60 | cc7c0f44 | Christos Stavrakakis | |
61 | 47d1d754 | Christos Stavrakakis | log.debug("Backend scores %s", backend_scores)
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62 | 47d1d754 | Christos Stavrakakis | |
63 | cc7c0f44 | Christos Stavrakakis | # Pick out the best
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64 | 7fede91e | Christos Stavrakakis | result = min(backend_scores, key=lambda (b, b_score): b_score) |
65 | 7fede91e | Christos Stavrakakis | backend = result[0]
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66 | cc7c0f44 | Christos Stavrakakis | |
67 | 7fede91e | Christos Stavrakakis | return backend
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68 | cc7c0f44 | Christos Stavrakakis | |
69 | cc7c0f44 | Christos Stavrakakis | |
70 | cc7c0f44 | Christos Stavrakakis | def vm_fits_in_backend(backend, vm): |
71 | 0cd83e6c | Christos Stavrakakis | has_disk = backend.dfree > vm['disk']
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72 | 0cd83e6c | Christos Stavrakakis | has_mem = backend.mfree > vm['ram']
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73 | 0cd83e6c | Christos Stavrakakis | # Consider each VM having 4 Virtual CPUs
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74 | 0cd83e6c | Christos Stavrakakis | vcpu_ratio = ((backend.pinst_cnt + 1) * 4) / backend.ctotal |
75 | 0cd83e6c | Christos Stavrakakis | # Consider max vcpu/cpu ratio 3
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76 | 0cd83e6c | Christos Stavrakakis | has_cpu = vcpu_ratio < 3
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77 | 0cd83e6c | Christos Stavrakakis | return has_cpu and has_disk and has_mem |
78 | cc7c0f44 | Christos Stavrakakis | |
79 | cc7c0f44 | Christos Stavrakakis | |
80 | cc7c0f44 | Christos Stavrakakis | def backend_score(backend, flavor): |
81 | 0cd83e6c | Christos Stavrakakis | mem_ratio = 1 - (backend.mfree / backend.mtotal)
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82 | 0cd83e6c | Christos Stavrakakis | disk_ratio = 1 - (backend.dfree / backend.dtotal)
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83 | 0cd83e6c | Christos Stavrakakis | cpu_ratio = ((backend.pinst_cnt + 1) * 4) / (backend.ctotal * 3) |
84 | 0cd83e6c | Christos Stavrakakis | return 0.5 * cpu_ratio + 0.5 * (mem_ratio + disk_ratio) |