From 3c229a3646a58e47d4d69c011f82c45ef3bb3c77 Mon Sep 17 00:00:00 2001 From: zsdc Date: Thu, 4 May 2023 22:26:17 +0300 Subject: cloud-init: T5190: Added Cloud-init pre-configurator Added a new service that starts before Cloud-init, waits for all network interfaces initialization, and if requested by config, checks which interfaces can get configuration via DHCP server and creates a corresponding Cloud-init network configuration. This protects from two situations: * when Cloud-init tries to get meta-data via eth0 (default and fallback variant for any data source which depends on network), but the real network is connected to another interface * when Cloud-init starts simultaneously with udev and initializes the first interface to get meta-data before it is renamed to eth0 by udev --- src/system/vyos-config-cloud-init.py | 169 +++++++++++++++++++++++++++++++++++ 1 file changed, 169 insertions(+) create mode 100755 src/system/vyos-config-cloud-init.py (limited to 'src/system') diff --git a/src/system/vyos-config-cloud-init.py b/src/system/vyos-config-cloud-init.py new file mode 100755 index 000000000..0a6c1f9bc --- /dev/null +++ b/src/system/vyos-config-cloud-init.py @@ -0,0 +1,169 @@ +#!/usr/bin/env python3 +# +# Copyright (C) 2023 VyOS maintainers and contributors +# +# This program is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License version 2 or later as +# published by the Free Software Foundation. +# +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program. If not, see . + +import logging +from concurrent.futures import ProcessPoolExecutor +from pathlib import Path +from subprocess import run, TimeoutExpired +from sys import exit + +from psutil import net_if_addrs, AF_LINK +from systemd.journal import JournalHandler +from yaml import safe_load + +from vyos.template import render + +# define a path to the configuration file and template +config_file = '/etc/cloud/cloud.cfg.d/20_vyos_network.cfg' +template_file = 'system/cloud_init_networking.j2' + + +def check_interface_dhcp(iface_name: str) -> bool: + """Check DHCP client can work on an interface + + Args: + iface_name (str): interface name + + Returns: + bool: check result + """ + dhclient_command: list[str] = [ + 'dhclient', '-4', '-1', '-q', '--no-pid', '-sf', '/bin/true', iface_name + ] + check_result = False + # try to get an IP address + # we use dhclient behavior here to speedup detection + # if dhclient receives a configuration and configure an interface + # it switch to background + # If no - it will keep running in foreground + try: + run(['ip', 'l', 'set', iface_name, 'up']) + run(dhclient_command, timeout=5) + check_result = True + except TimeoutExpired: + pass + finally: + run(['ip', 'l', 'set', iface_name, 'down']) + + logger.info(f'DHCP server was found on {iface_name}: {check_result}') + return check_result + + +def dhclient_cleanup() -> None: + """Clean up after dhclients + """ + run(['killall', 'dhclient']) + leases_file: Path = Path('/var/lib/dhcp/dhclient.leases') + leases_file.unlink(missing_ok=True) + logger.debug('cleaned up after dhclients') + + +def dict_interfaces() -> dict[str, str]: + """Return list of available network interfaces except loopback + + Returns: + list[str]: a list of interfaces + """ + interfaces_dict: dict[str, str] = {} + ifaces = net_if_addrs() + for iface_name, iface_addresses in ifaces.items(): + # we do not need loopback interface + if iface_name == 'lo': + continue + # check other interfaces for MAC addresses + for iface_addr in iface_addresses: + if iface_addr.family == AF_LINK and iface_addr.address: + interfaces_dict[iface_name] = iface_addr.address + continue + + logger.debug(f'found interfaces: {interfaces_dict}') + return interfaces_dict + + +def need_to_check() -> bool: + """Check if we need to perform DHCP checks + + Returns: + bool: check result + """ + # if cloud-init config does not exist, we do not need to do anything + ci_config_vyos = Path('/etc/cloud/cloud.cfg.d/20_vyos_custom.cfg') + if not ci_config_vyos.exists(): + logger.info( + 'No need to check interfaces: Cloud-init config file was not found') + return False + + # load configuration file + try: + config = safe_load(ci_config_vyos.read_text()) + except: + logger.error('Cloud-init config file has a wrong format') + return False + + # check if we have in config configured option + # vyos_config_options: + # network_preconfigure: true + if not config.get('vyos_config_options', {}).get('network_preconfigure'): + logger.info( + 'No need to check interfaces: Cloud-init config option "network_preconfigure" is not set' + ) + return False + + return True + + +if __name__ == '__main__': + # prepare logger + logger = logging.getLogger(__name__) + logger.addHandler(JournalHandler(SYSLOG_IDENTIFIER=Path(__file__).name)) + logger.setLevel(logging.INFO) + + # we need to give udev some time to rename all interfaces + # this is placed before need_to_check() call, because we are not always + # need to preconfigure cloud-init, but udev always need to finish its work + # before cloud-init start + run(['udevadm', 'settle']) + logger.info('udev finished its work, we continue') + + # do not perform any checks if this is not required + if not need_to_check(): + exit() + + # get list of interfaces and check them + interfaces_dhcp: list[dict[str, str]] = [] + interfaces_dict: dict[str, str] = dict_interfaces() + + with ProcessPoolExecutor(max_workers=len(interfaces_dict)) as executor: + iface_check_results = [{ + 'dhcp': executor.submit(check_interface_dhcp, iface_name), + 'append': { + 'name': iface_name, + 'mac': iface_mac + } + } for iface_name, iface_mac in interfaces_dict.items()] + + dhclient_cleanup() + + for iface_check_result in iface_check_results: + if iface_check_result.get('dhcp').result(): + interfaces_dhcp.append(iface_check_result.get('append')) + + # render cloud-init config + if interfaces_dhcp: + logger.debug('rendering cloud-init network configuration') + render(config_file, template_file, {'ifaces_list': interfaces_dhcp}) + + exit() -- cgit v1.2.3