root / doc / examples / dumb-allocator @ b3a447ef
History | View | Annotate | Download (2.9 kB)
1 |
#!/usr/bin/python |
---|---|
2 |
# |
3 |
|
4 |
# Copyright (C) 2008 Google Inc. |
5 |
# |
6 |
# This program is free software; you can redistribute it and/or modify |
7 |
# it under the terms of the GNU General Public License as published by |
8 |
# the Free Software Foundation; either version 2 of the License, or |
9 |
# (at your option) any later version. |
10 |
# |
11 |
# This program is distributed in the hope that it will be useful, but |
12 |
# WITHOUT ANY WARRANTY; without even the implied warranty of |
13 |
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
14 |
# General Public License for more details. |
15 |
# |
16 |
# You should have received a copy of the GNU General Public License |
17 |
# along with this program; if not, write to the Free Software |
18 |
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
19 |
# 02110-1301, USA. |
20 |
|
21 |
"""Simple first-fit allocator for ganeti instance allocation framework. |
22 |
|
23 |
This allocator just iterates over the nodes and selects the first one |
24 |
that fits in both memory and disk space, without any consideration for |
25 |
equal spread or VCPU oversubscription. |
26 |
|
27 |
""" |
28 |
|
29 |
import simplejson |
30 |
import sys |
31 |
|
32 |
|
33 |
def SelectNode(nodes, request, to_skip): |
34 |
"""Select a node for the given instance |
35 |
|
36 |
""" |
37 |
disk_size = request["disk_space_total"] |
38 |
selected = None |
39 |
for nname, ninfo in nodes.iteritems(): |
40 |
if nname in to_skip: |
41 |
continue |
42 |
if request["memory"] > ninfo["free_memory"]: |
43 |
continue |
44 |
if disk_size > ninfo["free_disk"]: |
45 |
continue |
46 |
selected = nname |
47 |
break |
48 |
return selected |
49 |
|
50 |
|
51 |
def OutputError(text, exit_code=1): |
52 |
"""Builds an error response with a given info message. |
53 |
|
54 |
""" |
55 |
error = { |
56 |
"success": False, |
57 |
"info": text, |
58 |
"nodes": [], |
59 |
} |
60 |
print simplejson.dumps(error, indent=2) |
61 |
return exit_code |
62 |
|
63 |
|
64 |
def main(): |
65 |
"""Main function. |
66 |
|
67 |
""" |
68 |
if len(sys.argv) < 2: |
69 |
print >> sys.stderr, "Usage: %s cluster.json" % (sys.argv[0]) |
70 |
return 1 |
71 |
|
72 |
data = simplejson.load(open(sys.argv[1])) |
73 |
|
74 |
nodes = data["nodes"] |
75 |
request = data["request"] |
76 |
req_type = request["type"] |
77 |
if req_type == "allocate": |
78 |
forbidden_nodes = [] |
79 |
inst_data = request |
80 |
elif req_type == "relocate": |
81 |
idict = data["instances"][request["name"]] |
82 |
forbidden_nodes = idict["nodes"] |
83 |
inst_data = idict |
84 |
inst_data["disk_space_total"] = request["disk_space_total"] |
85 |
else: |
86 |
return OutputError("Unsupported allocator mode '%s'" % req_type) |
87 |
|
88 |
result_nodes = [] |
89 |
while len(result_nodes) < request["required_nodes"]: |
90 |
new_selection = SelectNode(nodes, inst_data, result_nodes+forbidden_nodes) |
91 |
if new_selection is None: |
92 |
return OutputError("Can't find a suitable node for position %s" |
93 |
" (already selected: %s)" % |
94 |
(len(result_nodes) + 1, ", ".join(result_nodes)), |
95 |
exit_code=0) |
96 |
result_nodes.append(new_selection) |
97 |
|
98 |
result = { |
99 |
"success": True, |
100 |
"info": "Allocation successful", |
101 |
"nodes": result_nodes, |
102 |
} |
103 |
print simplejson.dumps(result, indent=2) |
104 |
return 0 |
105 |
|
106 |
|
107 |
if __name__ == "__main__": |
108 |
sys.exit(main()) |