ironic-python-agent/ironic_python_agent/agent.py
Dmitry Tantsur 6829d34c15 Bind to interface routable to the ironic host, not a random one
Binding to the first interface that has an IP address is error-prone: there is
no guarantee that ironic can reach us via this inteface. It is much safer to
detect the interface facing ironic and bind to it.

Unused LookupAgentInterfaceError exception is deleted.

The TinyIPA build also requires iptables dependency at build time to insert the
required kernel modules.

Closes-Bug: #1558956
Change-Id: I9586805e6c7f52a50834bc03efeb72d1faa6cb65
2016-03-21 14:21:12 +00:00

325 lines
11 KiB
Python

# Copyright 2013 Rackspace, Inc.
#
# 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.
import os
import random
import select
import socket
import threading
import time
from oslo_concurrency import processutils
from oslo_log import log
import pkg_resources
from six.moves.urllib import parse as urlparse
from stevedore import extension
from wsgiref import simple_server
from ironic_python_agent.api import app
from ironic_python_agent import encoding
from ironic_python_agent import errors
from ironic_python_agent.extensions import base
from ironic_python_agent import hardware
from ironic_python_agent import inspector
from ironic_python_agent import ironic_api_client
from ironic_python_agent import utils
LOG = log.getLogger(__name__)
def _time():
"""Wraps time.time() for simpler testing."""
return time.time()
class IronicPythonAgentStatus(encoding.Serializable):
"""Represents the status of an agent."""
serializable_fields = ('started_at', 'version')
def __init__(self, started_at, version):
self.started_at = started_at
self.version = version
class IronicPythonAgentHeartbeater(threading.Thread):
"""Thread that periodically heartbeats to Ironic."""
# If we could wait at most N seconds between heartbeats (or in case of an
# error) we will instead wait r x N seconds, where r is a random value
# between these multipliers.
min_jitter_multiplier = 0.3
max_jitter_multiplier = 0.6
# Exponential backoff values used in case of an error. In reality we will
# only wait a portion of either of these delays based on the jitter
# multipliers.
initial_delay = 1.0
max_delay = 300.0
backoff_factor = 2.7
def __init__(self, agent):
"""Initialize the heartbeat thread.
:param agent: an :class:`ironic_python_agent.agent.IronicPythonAgent`
instance.
"""
super(IronicPythonAgentHeartbeater, self).__init__()
self.agent = agent
self.api = ironic_api_client.APIClient(agent.api_url,
agent.driver_name)
self.error_delay = self.initial_delay
self.reader = None
self.writer = None
def run(self):
"""Start the heartbeat thread."""
# The first heartbeat happens immediately
LOG.info('starting heartbeater')
interval = 0
self.agent.set_agent_advertise_addr()
self.reader, self.writer = os.pipe()
p = select.poll()
p.register(self.reader, select.POLLIN)
try:
while True:
if p.poll(interval * 1000):
if os.read(self.reader, 1) == 'a':
break
self.do_heartbeat()
interval_multiplier = random.uniform(
self.min_jitter_multiplier,
self.max_jitter_multiplier)
interval = self.agent.heartbeat_timeout * interval_multiplier
log_msg = 'sleeping before next heartbeat, interval: {0}'
LOG.info(log_msg.format(interval))
finally:
os.close(self.reader)
os.close(self.writer)
self.reader = None
self.writer = None
def do_heartbeat(self):
"""Send a heartbeat to Ironic."""
try:
self.api.heartbeat(
uuid=self.agent.get_node_uuid(),
advertise_address=self.agent.advertise_address
)
self.error_delay = self.initial_delay
LOG.info('heartbeat successful')
except errors.HeartbeatConflictError:
LOG.warning('conflict error sending heartbeat')
self.error_delay = min(self.error_delay * self.backoff_factor,
self.max_delay)
except Exception:
LOG.exception('error sending heartbeat')
self.error_delay = min(self.error_delay * self.backoff_factor,
self.max_delay)
def force_heartbeat(self):
os.write(self.writer, 'b')
def stop(self):
"""Stop the heartbeat thread."""
if self.writer is not None:
LOG.info('stopping heartbeater')
os.write(self.writer, 'a')
return self.join()
class IronicPythonAgent(base.ExecuteCommandMixin):
"""Class for base agent functionality."""
def __init__(self, api_url, advertise_address, listen_address,
ip_lookup_attempts, ip_lookup_sleep, network_interface,
lookup_timeout, lookup_interval, driver_name, standalone):
super(IronicPythonAgent, self).__init__()
self.ext_mgr = extension.ExtensionManager(
namespace='ironic_python_agent.extensions',
invoke_on_load=True,
propagate_map_exceptions=True,
invoke_kwds={'agent': self},
)
self.api_url = api_url
self.driver_name = driver_name
self.api_client = ironic_api_client.APIClient(self.api_url,
self.driver_name)
self.listen_address = listen_address
self.advertise_address = advertise_address
self.version = pkg_resources.get_distribution('ironic-python-agent')\
.version
self.api = app.VersionSelectorApplication(self)
self.heartbeater = IronicPythonAgentHeartbeater(self)
self.heartbeat_timeout = None
self.started_at = None
self.node = None
# lookup timeout in seconds
self.lookup_timeout = lookup_timeout
self.lookup_interval = lookup_interval
self.ip_lookup_attempts = ip_lookup_attempts
self.ip_lookup_sleep = ip_lookup_sleep
self.network_interface = network_interface
self.standalone = standalone
def get_status(self):
"""Retrieve a serializable status.
:returns: a :class:`ironic_python_agent.agent.IronicPythonAgent`
instance describing the agent's status.
"""
return IronicPythonAgentStatus(
started_at=self.started_at,
version=self.version
)
def _get_route_source(self, dest):
"""Get the IP address to send packages to destination."""
try:
out, _err = utils.execute('ip', 'route', 'get', dest)
except (EnvironmentError, processutils.ProcessExecutionError) as e:
LOG.warning('Cannot get route to host %(dest)s: %(err)s',
{'dest': dest, 'err': e})
return
try:
return out.strip().split('\n')[0].split('src')[1].strip()
except IndexError:
LOG.warning('No route to host %(dest)s, route record: %(rec)s',
{'dest': dest, 'rec': out})
def set_agent_advertise_addr(self):
"""Set advertised IP address for the agent, if not already set.
If agent's advertised IP address is still default (None), try to
find a better one. If the agent's network interface is None, replace
that as well.
:raises: LookupAgentIPError if an IP address could not be found
"""
if self.advertise_address[0] is not None:
return
found_ip = None
if self.network_interface is not None:
# TODO(dtantsur): deprecate this
found_ip = hardware.dispatch_to_managers('get_ipv4_addr',
self.network_interface)
else:
url = urlparse.urlparse(self.api_url)
ironic_host = url.hostname
# Try resolving it in case it's not an IP address
try:
ironic_host = socket.gethostbyname(ironic_host)
except socket.gaierror:
LOG.debug('Count not resolve %s, maybe no DNS', ironic_host)
for attempt in range(self.ip_lookup_attempts):
found_ip = self._get_route_source(ironic_host)
if found_ip:
break
time.sleep(self.ip_lookup_sleep)
if found_ip:
self.advertise_address = (found_ip,
self.advertise_address[1])
else:
raise errors.LookupAgentIPError('Agent could not find a valid IP '
'address.')
def get_node_uuid(self):
"""Get UUID for Ironic node.
If the agent has not yet heartbeated to Ironic, it will not have
the UUID and this will raise an exception.
:returns: A string containing the UUID for the Ironic node.
:raises: UnknownNodeError if UUID is unknown.
"""
if self.node is None or 'uuid' not in self.node:
raise errors.UnknownNodeError()
return self.node['uuid']
def list_command_results(self):
"""Get a list of command results.
:returns: list of :class:`ironic_python_agent.extensions.base.
BaseCommandResult` objects.
"""
return list(self.command_results.values())
def get_command_result(self, result_id):
"""Get a specific command result by ID.
:returns: a :class:`ironic_python_agent.extensions.base.
BaseCommandResult` object.
:raises: RequestedObjectNotFoundError if command with the given ID
is not found.
"""
try:
return self.command_results[result_id]
except KeyError:
raise errors.RequestedObjectNotFoundError('Command Result',
result_id)
def force_heartbeat(self):
if not self.standalone:
self.heartbeater.force_heartbeat()
def run(self):
"""Run the Ironic Python Agent."""
# Get the UUID so we can heartbeat to Ironic. Raises LookupNodeError
# if there is an issue (uncaught, restart agent)
self.started_at = _time()
# Cached hw managers at runtime, not load time. See bug 1490008.
hardware.load_managers()
if not self.standalone:
# Inspection should be started before call to lookup, otherwise
# lookup will fail due to unknown MAC.
uuid = inspector.inspect()
content = self.api_client.lookup_node(
hardware_info=hardware.dispatch_to_managers(
'list_hardware_info'),
timeout=self.lookup_timeout,
starting_interval=self.lookup_interval,
node_uuid=uuid)
self.node = content['node']
self.heartbeat_timeout = content['heartbeat_timeout']
wsgi = simple_server.make_server(
self.listen_address[0],
self.listen_address[1],
self.api,
server_class=simple_server.WSGIServer)
if not self.standalone:
# Don't start heartbeating until the server is listening
self.heartbeater.start()
try:
wsgi.serve_forever()
except BaseException:
LOG.exception('shutting down')
if not self.standalone:
self.heartbeater.stop()