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# Microsoft Azure Linux Agent
#
# Copyright 2014 Microsoft Corporation
#
# 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.
#
# Requires Python 2.4+ and Openssl 1.0+
#
import os
import socket
import time
import threading
import azurelinuxagent.common.conf as conf
import azurelinuxagent.common.logger as logger
from azurelinuxagent.common.dhcp import get_dhcp_handler
from azurelinuxagent.common.event import add_periodic, WALAEventOperation
from azurelinuxagent.common.osutil import get_osutil
from azurelinuxagent.common.protocol import get_protocol_util
from azurelinuxagent.common.version import AGENT_NAME, CURRENT_VERSION
def get_env_handler():
return EnvHandler()
class EnvHandler(object):
"""
Monitor changes to dhcp and hostname.
If dhcp clinet process re-start has occurred, reset routes, dhcp with fabric.
Monitor scsi disk.
If new scsi disk found, set timeout
"""
def __init__(self):
self.osutil = get_osutil()
self.dhcp_handler = get_dhcp_handler()
self.protocol_util = get_protocol_util()
self.stopped = True
self.hostname = None
self.dhcpid = None
self.server_thread = None
self.dhcp_warning_enabled = True
def run(self):
if not self.stopped:
logger.info("Stop existing env monitor service.")
self.stop()
self.stopped = False
logger.info("Start env monitor service.")
self.dhcp_handler.conf_routes()
self.hostname = self.osutil.get_hostname_record()
self.dhcpid = self.osutil.get_dhcp_pid()
self.server_thread = threading.Thread(target=self.monitor)
self.server_thread.setDaemon(True)
self.server_thread.start()
def monitor(self):
"""
Monitor firewall rules
Monitor dhcp client pid and hostname.
If dhcp clinet process re-start has occurred, reset routes.
"""
protocol = self.protocol_util.get_protocol()
while not self.stopped:
self.osutil.remove_rules_files()
# Disable setting firewall for now, regardless of configuration switch
# if conf.enable_firewall():
# success = self.osutil.enable_firewall(
# dst_ip=protocol.endpoint,
# uid=os.getuid())
# add_periodic(
# logger.EVERY_HOUR,
# AGENT_NAME,
# version=CURRENT_VERSION,
# op=WALAEventOperation.Firewall,
# is_success=success,
# log_event=True)
self.osutil.remove_firewall()
timeout = conf.get_root_device_scsi_timeout()
if timeout is not None:
self.osutil.set_scsi_disks_timeout(timeout)
if conf.get_monitor_hostname():
self.handle_hostname_update()
self.handle_dhclient_restart()
time.sleep(5)
def handle_hostname_update(self):
curr_hostname = socket.gethostname()
if curr_hostname != self.hostname:
logger.info("EnvMonitor: Detected hostname change: {0} -> {1}",
self.hostname,
curr_hostname)
self.osutil.set_hostname(curr_hostname)
self.osutil.publish_hostname(curr_hostname)
self.hostname = curr_hostname
def handle_dhclient_restart(self):
if self.dhcpid is None:
if self.dhcp_warning_enabled:
logger.warn("Dhcp client is not running. ")
self.dhcpid = self.osutil.get_dhcp_pid()
# disable subsequent error logging
self.dhcp_warning_enabled = self.dhcpid is not None
return
#The dhcp process hasn't changed since last check
if self.osutil.check_pid_alive(self.dhcpid.strip()):
return
newpid = self.osutil.get_dhcp_pid()
if newpid is not None and newpid != self.dhcpid:
logger.info("EnvMonitor: Detected dhcp client restart. "
"Restoring routing table.")
self.dhcp_handler.conf_routes()
self.dhcpid = newpid
def stop(self):
"""
Stop server comminucation and join the thread to main thread.
"""
self.stopped = True
if self.server_thread is not None:
self.server_thread.join()
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