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# Copyright 2014 Canonical Ltd. This software is licensed under the
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# GNU Affero General Public License version 3 (see the file LICENSE).
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"""Management command: upgrade the cluster.
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This module implements the `ActionScript` interface for pserv commands.
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Use the upgrade-cluster command when the MAAS code has been updated (e.g. while
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installing a package ugprade, from the packaging) to perform any data
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migrations that the new version may require.
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This maintains a list of upgrade hooks, each representing a data migration
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that was needed at some point in development of the MAAS cluster codebase.
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All these hooks get run, in chronological order. There is no record of
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updates that have already been performed; each hook figures out for itself
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whether its migration is needed.
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Backwards migrations are not supported.
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from __future__ import (
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from logging import getLogger
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from provisioningserver.boot.tftppath import drill_down
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from provisioningserver.config import (
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from provisioningserver.utils import (
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logger = getLogger(__name__)
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def find_old_imports(tftproot):
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"""List pre-Simplestreams boot images.
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Supports the `generate_boot_resources_config` upgrade hook. Returns a set
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of tuples (arch, subarch, release) describing all of the images found.
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if not os.path.isdir(tftproot):
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for level in ['arch', 'subarch', 'release', 'purpose']:
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paths = drill_down(tftproot, paths)
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(arch, subarch, release)
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for [root, arch, subarch, release, purpose] in paths
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def generate_selections(images):
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"""Generate `selections` stanzas to match pre-existing boot images.
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Supports the `generate_boot_resources_config` upgrade hook.
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:param images: An iterable of (arch, subarch, release) tuples as returned
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by `find_old_imports`.
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:return: A list of dicts, each describing one `selections` stanza for the
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`bootresources.yaml` file.
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# No old images found.
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# Return one "selections" stanza per image. This could be cleverer
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# and combine multiple architectures/subarchitectures, but there would
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# have to be a clear gain. Simple is good.
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'subarches': [subarch],
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for arch, subarch, release in sorted(images)
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def generate_updated_config(config, old_images):
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"""Return an updated version of a config dict.
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Supports the `generate_boot_resources_config` upgrade hook.
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This clears the `configure_me` flag, and replaces all sources'
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`selections` stanzas with ones based on the old boot images.
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:param config: A config dict, as loaded from `bootresources.yaml`.
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:param old_images: Old-style boot images, as returned by
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`find_old_imports`. If `None`, the existing `selections` are left
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:return: An updated version of `config` with the above changes.
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config = config.copy()
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# Remove the configure_me item. It's there exactly to tell us that we
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# haven't done this rewrite yet.
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del config['boot']['configure_me']
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if old_images is None:
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# If we found old images, rewrite the selections.
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if len(old_images) != 0:
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new_selections = generate_selections(old_images)
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for source in config['boot']['sources']:
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source['selections'] = new_selections
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def extract_top_comment(input_file):
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"""Return just the comment at the top of `input_file`.
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Supports the `generate_boot_resources_config` upgrade hook.
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for line in read_text_file(input_file).splitlines():
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stripped_line = line.lstrip()
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if stripped_line != '' and not stripped_line.startswith('#'):
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# Not an empty line or comment any more. Stop.
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return '\n'.join(lines) + '\n'
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def update_config_file(config_file, new_config):
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"""Replace configuration data in `config_file` with `new_config`.
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Supports the `generate_boot_resources_config` upgrade hook.
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The first part of the config file, up to the first text that isn't a
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comment, is kept intact. The part after that is overwritten with YAML
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for the new configuration.
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header = extract_top_comment(config_file)
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data = yaml.safe_dump(new_config, default_flow_style=False)
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content = (header + data).encode('utf-8')
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atomic_write(content, config_file, mode=0644)
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BootConfig.flush_cache(config_file)
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def rewrite_boot_resources_config(config_file):
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"""Rewrite the `bootresources.yaml` configuration.
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Supports the `generate_boot_resources_config` upgrade hook.
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# Look for images using the old tftp root setting, not the tftp
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# resource_root setting. The latter points to where the newer,
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# Simplestreams-based boot images live.
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# This should be the final use of the old tftp root setting. After this
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# has run, it serves no more purpose.
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tftproot = Config.load_from_cache()['tftp']['root']
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config = BootConfig.load_from_cache(config_file)
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old_images = find_old_imports(tftproot)
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new_config = generate_updated_config(config, old_images)
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update_config_file(config_file, new_config)
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def generate_boot_resources_config():
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"""Upgrade hook: rewrite `bootresources.yaml` based on boot images.
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This finds boot images downloaded into the old, pre-Simplestreams tftp
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root, and writes a boot-resources configuration to import a similar set of
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images using Simplestreams.
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config_file = locate_config('bootresources.yaml')
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boot_resources = BootConfig.load_from_cache(config_file)
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if boot_resources['boot'].get('configure_me', False):
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rewrite_boot_resources_config(config_file)
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# Upgrade hooks, from oldest to newest. The hooks are callables, taking no
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# arguments. They are called in order.
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# Each hook figures out for itself whether its changes are needed. There is
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# no record of previous upgrades.
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generate_boot_resources_config,
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def add_arguments(parser):
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"""Add this command's options to the `ArgumentParser`.
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Specified by the `ActionScript` interface.
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# This command accepts no arguments.
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# The docstring for the "run" function is also the command's documentation.
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"""Perform any data migrations needed for upgrading this cluster."""
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for hook in UPGRADE_HOOKS:
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removed
src/provisioningserver/upgrade_cluster.py
