deb-ceilometer/ceilometer/compute/discovery.py
Nejc Saje 9a2f8618de Central agent work-load partitioning
Provides a mechanism to allow the central agent to be horizontally
scaled out, such that each agent polls a disjoint subset of resources.

This is achieved through the use of `tooz` library for distributed
coordination.

If a service wants to use work-load partitioning, it must first
create a PartitionCoordinator object and call its `heartbeat` method
periodically.

To distribute a set of resources over multiple agents, use the
`extract_my_subset` method of the PartitionCoordinator that filters an
iterable, returning only the resources assigned to us.

The `PartitionCoordinator` uses `tooz` to figure out which agents are
in the same group and figures out which resources belong to the
current agent.

DocImpact
Change-Id: I7adef87b03129f4f8b38109bf547c7403cc6adad
Implements: blueprint central-agent-partitioning
2014-09-01 05:31:58 -04:00

49 lines
1.5 KiB
Python

#
# Copyright 2014 Red Hat, Inc
#
# Author: Eoghan Glynn <eglynn@redhat.com>
#
# 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 oslo.config import cfg
from ceilometer import nova_client
from ceilometer import plugin
OPTS = [
cfg.BoolOpt('workload_partitioning',
default=False,
help='Enable work-load partitioning, allowing multiple '
'compute agents to be run simultaneously.')
]
cfg.CONF.register_opts(OPTS, group='compute')
class InstanceDiscovery(plugin.DiscoveryBase):
def __init__(self):
super(InstanceDiscovery, self).__init__()
self.nova_cli = nova_client.Client()
def discover(self, param=None):
"""Discover resources to monitor."""
instances = self.nova_cli.instance_get_all_by_host(cfg.CONF.host)
return [i for i in instances
if getattr(i, 'OS-EXT-STS:vm_state', None) != 'error']
@property
def group_id(self):
if cfg.CONF.compute.workload_partitioning:
return cfg.CONF.host
else:
return None