diff options
Diffstat (limited to 'cloudinit/config/cc_grub_dpkg.py')
| -rw-r--r-- | cloudinit/config/cc_grub_dpkg.py | 95 |
1 files changed, 70 insertions, 25 deletions
diff --git a/cloudinit/config/cc_grub_dpkg.py b/cloudinit/config/cc_grub_dpkg.py index a323edfa..7888464e 100644 --- a/cloudinit/config/cc_grub_dpkg.py +++ b/cloudinit/config/cc_grub_dpkg.py @@ -1,8 +1,9 @@ -# Copyright (C) 2009-2010 Canonical Ltd. +# Copyright (C) 2009-2010, 2020 Canonical Ltd. # Copyright (C) 2012 Hewlett-Packard Development Company, L.P. # # Author: Scott Moser <scott.moser@canonical.com> # Author: Juerg Haefliger <juerg.haefliger@hp.com> +# Author: Matthew Ruffell <matthew.ruffell@canonical.com> # # This file is part of cloud-init. See LICENSE file for license information. @@ -15,15 +16,15 @@ Configure which device is used as the target for grub installation. This module should work correctly by default without any user configuration. It can be enabled/disabled using the ``enabled`` config key in the ``grub_dpkg`` config dict. The global config key ``grub-dpkg`` is an alias for ``grub_dpkg``. If no -installation device is specified this module will look for the first existing -device in: +installation device is specified this module will execute grub-probe to +determine which disk the /boot directory is associated with. - - ``/dev/sda`` - - ``/dev/vda`` - - ``/dev/xvda`` - - ``/dev/sda1`` - - ``/dev/vda1`` - - ``/dev/xvda1`` +The value which is placed into the debconf database is in the format which the +grub postinstall script expects. Normally, this is a /dev/disk/by-id/ value, +but we do fallback to the plain disk name if a by-id name is not present. + +If this module is executed inside a container, then the debconf database is +seeded with empty values, and install_devices_empty is set to true. **Internal name:** ``cc_grub_dpkg`` @@ -43,10 +44,66 @@ device in: import os from cloudinit import util +from cloudinit.util import ProcessExecutionError distros = ['ubuntu', 'debian'] +def fetch_idevs(log): + """ + Fetches the /dev/disk/by-id device grub is installed to. + Falls back to plain disk name if no by-id entry is present. + """ + disk = "" + devices = [] + + try: + # get the root disk where the /boot directory resides. + disk = util.subp(['grub-probe', '-t', 'disk', '/boot'], + capture=True)[0].strip() + except ProcessExecutionError as e: + # grub-common may not be installed, especially on containers + # FileNotFoundError is a nested exception of ProcessExecutionError + if isinstance(e.reason, FileNotFoundError): + log.debug("'grub-probe' not found in $PATH") + # disks from the container host are present in /proc and /sys + # which is where grub-probe determines where /boot is. + # it then checks for existence in /dev, which fails as host disks + # are not exposed to the container. + elif "failed to get canonical path" in e.stderr: + log.debug("grub-probe 'failed to get canonical path'") + else: + # something bad has happened, continue to log the error + raise + except Exception: + util.logexc(log, "grub-probe failed to execute for grub-dpkg") + + if not disk or not os.path.exists(disk): + # If we failed to detect a disk, we can return early + return '' + + try: + # check if disk exists and use udevadm to fetch symlinks + devices = util.subp( + ['udevadm', 'info', '--root', '--query=symlink', disk], + capture=True + )[0].strip().split() + except Exception: + util.logexc( + log, "udevadm DEVLINKS symlink query failed for disk='%s'", disk + ) + + log.debug('considering these device symlinks: %s', ','.join(devices)) + # filter symlinks for /dev/disk/by-id entries + devices = [dev for dev in devices if 'disk/by-id' in dev] + log.debug('filtered to these disk/by-id symlinks: %s', ','.join(devices)) + # select first device if there is one, else fall back to plain name + idevs = sorted(devices)[0] if devices else disk + log.debug('selected %s', idevs) + + return idevs + + def handle(name, cfg, _cloud, log, _args): mycfg = cfg.get("grub_dpkg", cfg.get("grub-dpkg", {})) @@ -62,22 +119,10 @@ def handle(name, cfg, _cloud, log, _args): idevs_empty = util.get_cfg_option_str( mycfg, "grub-pc/install_devices_empty", None) - if ((os.path.exists("/dev/sda1") and not os.path.exists("/dev/sda")) or - (os.path.exists("/dev/xvda1") and not os.path.exists("/dev/xvda"))): - if idevs is None: - idevs = "" - if idevs_empty is None: - idevs_empty = "true" - else: - if idevs_empty is None: - idevs_empty = "false" - if idevs is None: - idevs = "/dev/sda" - for dev in ("/dev/sda", "/dev/vda", "/dev/xvda", - "/dev/sda1", "/dev/vda1", "/dev/xvda1"): - if os.path.exists(dev): - idevs = dev - break + if idevs is None: + idevs = fetch_idevs(log) + if idevs_empty is None: + idevs_empty = "false" if idevs else "true" # now idevs and idevs_empty are set to determined values # or, those set by user |