From b68da99b22614f0207645b3df2566f6187c571d2 Mon Sep 17 00:00:00 2001 From: Brian Elliott Date: Fri, 28 Sep 2012 03:43:33 +0000 Subject: [PATCH] Num instances scheduler filter Allow for scheduler filtering based on number of instances already assigned to that host. FLAGS.max_instances_per_host controls the maximum number of instances allowed per host. Change-Id: Id3e8973311ea5ac8db2d9e4e594a5288a9e3f94d --- .../scheduler/filters/num_instances_filter.py | 42 +++++++++++++++++++ nova/tests/scheduler/test_host_filters.py | 14 +++++++ 2 files changed, 56 insertions(+) create mode 100644 nova/scheduler/filters/num_instances_filter.py diff --git a/nova/scheduler/filters/num_instances_filter.py b/nova/scheduler/filters/num_instances_filter.py new file mode 100644 index 000000000000..e96539c0c37a --- /dev/null +++ b/nova/scheduler/filters/num_instances_filter.py @@ -0,0 +1,42 @@ +# Copyright (c) 2012 OpenStack, LLC. +# All Rights Reserved. +# +# 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. + +from nova import flags +from nova.openstack.common import cfg +from nova.openstack.common import log as logging +from nova.scheduler import filters + +LOG = logging.getLogger(__name__) + +max_instances_per_host_opt = cfg.IntOpt("max_instances_per_host", + default=50, + help="Ignore hosts that have too many instances") + +FLAGS = flags.FLAGS +FLAGS.register_opt(max_instances_per_host_opt) + + +class NumInstancesFilter(filters.BaseHostFilter): + """Filter out hosts with too many instances""" + + def host_passes(self, host_state, filter_properties): + num_instances = host_state.num_instances + max_instances = FLAGS.max_instances_per_host + passes = num_instances < max_instances + if not passes: + LOG.debug(_("%(host_state)s fails num_instances check: Max " + "instances per host is set to %(max_instances)s"), + locals()) + return passes diff --git a/nova/tests/scheduler/test_host_filters.py b/nova/tests/scheduler/test_host_filters.py index b1e1ec8972fc..bc62ad6f1008 100644 --- a/nova/tests/scheduler/test_host_filters.py +++ b/nova/tests/scheduler/test_host_filters.py @@ -1292,5 +1292,19 @@ class HostFiltersTestCase(test.TestCase): filt_cls = self.class_map['IoOpsFilter']() host = fakes.FakeHostState('host1', 'compute', {'num_io_ops': 8}) + + def test_filter_num_instances_passes(self): + self.flags(max_instances_per_host=5) + filt_cls = self.class_map['NumInstancesFilter']() + host = fakes.FakeHostState('host1', 'compute', + {'num_instances': 4}) + filter_properties = {} + self.assertTrue(filt_cls.host_passes(host, filter_properties)) + + def test_filter_num_instances_fails(self): + self.flags(max_instances_per_host=5) + filt_cls = self.class_map['NumInstancesFilter']() + host = fakes.FakeHostState('host1', 'compute', + {'num_instances': 5}) filter_properties = {} self.assertFalse(filt_cls.host_passes(host, filter_properties))