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authorPedro Alvarez <pedro.alvarez@codethink.co.uk>2014-02-20 18:41:28 (GMT)
committerPedro Alvarez <pedro.alvarez@codethink.co.uk>2014-03-06 16:50:21 (GMT)
commit3ff52dc3935ae52b5b633a98eec1eb1ff3be0f29 (patch)
tree042461f6a6fcf65732c813c702d2e35ead86b917
parent5afdc1e8e66c565bbe2d5c8bb4669351043a3841 (diff)
downloadtbdiff-3ff52dc3935ae52b5b633a98eec1eb1ff3be0f29.tar.gz
Add script to modify the bootloader and manage different parallel OS.
This is part of the upgrades work. With this tool you can now switch between versions of the OS, remove a version, list all the versions present in the system, get the default version and the running version, and deploy a new system. All of the above is possible with the following subcommands: - list - deploy - get-default - get-running - remove - set-default It also activates a bootloader menu to choose a version to boot. The menu is important to make sure the user can boot the old OS if the new kernel doesn't work.
-rw-r--r--Makefile.am3
-rw-r--r--configure.ac3
-rw-r--r--system-version-manager/Makefile.am20
-rwxr-xr-xsystem-version-manager/system-version-manager314
4 files changed, 338 insertions, 2 deletions
diff --git a/Makefile.am b/Makefile.am
index 746bd9c..e3d38ef 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -1,6 +1,6 @@
# vi:set ts=8 sw=8 noet ai nocindent:
# -
-# Copyright (c) 2011-2013 Codethink Ltd.
+# Copyright (c) 2011-2014 Codethink Ltd.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License Version 2 as
@@ -22,6 +22,7 @@ SUBDIRS = \
tb-switch \
tb-update \
baserock-system-config-sync \
+ system-version-manager \
tests
.PHONY: ChangeLog
diff --git a/configure.ac b/configure.ac
index 17ec2dd..0e12f62 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1,6 +1,6 @@
# vi:set et ai sw=2 sts=2 ts=2: */
# -
-# Copyright (c) 2011-2012 Codethink Ltd.
+# Copyright (c) 2011-2014 Codethink Ltd.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License Version 2 as
@@ -122,6 +122,7 @@ tbdiff-deploy/Makefile
tb-switch/Makefile
tb-update/Makefile
baserock-system-config-sync/Makefile
+system-version-manager/Makefile
tests/Makefile
])
diff --git a/system-version-manager/Makefile.am b/system-version-manager/Makefile.am
new file mode 100644
index 0000000..ddd0588
--- /dev/null
+++ b/system-version-manager/Makefile.am
@@ -0,0 +1,20 @@
+# vi:set ts=8 sw=8 noet ai nocindent:
+# -
+# Copyright (c) 2014 Codethink Ltd.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License Version 2 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, write to the Free Software Foundation, Inc.,
+# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+# vi:set ts=8 sw=8 noet ai nocindent:
+
+bin_SCRIPTS = \
+ system-version-manager
diff --git a/system-version-manager/system-version-manager b/system-version-manager/system-version-manager
new file mode 100755
index 0000000..261333b
--- /dev/null
+++ b/system-version-manager/system-version-manager
@@ -0,0 +1,314 @@
+#!/usr/bin/python
+#
+# Copyright (C) 2014 Codethink Limited
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; version 2 of the License.
+#
+# 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, write to the Free Software Foundation, Inc.,
+# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+
+import argparse
+import subprocess
+import tempfile
+import os
+import sys
+import shutil
+
+
+class AppException(Exception):
+
+ pass
+
+
+class SystemNotCompatibleError(Exception):
+
+ pass
+
+
+class SystemVersionManager(object):
+
+ def __init__(self, args, mount_dir):
+ self.device, self.current_system = self._get_mount_info()
+ self.mount_dir = mount_dir
+
+ # create the top-level parser
+ parser = argparse.ArgumentParser(prog='system-version-manager')
+ subparsers = parser.add_subparsers(help='sub-command help')
+
+ # create the parser for the "list" command
+ parser_list = subparsers.add_parser('list',
+ help='list show you a list of systems')
+ parser_list.set_defaults(action='list')
+
+ # create the parser for the "deploy" command
+ parser_deploy= subparsers.add_parser('deploy',
+ help='deploy an updated base OS version to the running Baserock system')
+ parser_deploy.set_defaults(action='deploy')
+ parser_deploy.add_argument('location')
+
+ # create the parser for the "get-default" command
+ parser_get_default = subparsers.add_parser('get-default',
+ help='prints the default system')
+ parser_get_default.set_defaults(action='get-default')
+
+ # create the parser for the "get-running" command
+ parser_get_running = subparsers.add_parser('get-running',
+ help='prints the running system')
+ parser_get_running.set_defaults(action='get-running')
+
+ # create the parser for the "remove" command
+ parser_remove = subparsers.add_parser('remove', help='remove a system')
+ parser_remove.add_argument('system_name', help='name of the system to remove')
+ parser_remove.set_defaults(action='remove')
+
+ # create the parser for the "set-default" command
+ parser_set_default = subparsers.add_parser('set-default',
+ help='set a system as default')
+ parser_set_default.add_argument('system_name', help='name of the system to set')
+ parser_set_default.set_defaults(action='set-default')
+
+ self.args = parser.parse_args(args[1:])
+
+ def status(self, msg, *args):
+ print msg % args
+
+ def _check_system_exists(self, system_name):
+ systems_list = self._get_systems()
+
+ if system_name not in systems_list:
+ sys.stderr.write("ERROR: the system %s doesn't exist\n" % system_name)
+ sys.exit(1)
+
+ # To get the systems the script lists the systems under the 'systems'
+ # folder which are directories and are not symlinks
+ def _get_systems(self):
+ systems = os.path.join(self.mount_dir, 'systems')
+ return [filename for filename in os.listdir(systems)
+ if os.path.isdir(os.path.join(systems, filename))
+ and not os.path.islink(os.path.join(systems, filename))]
+
+ # To check which system is the default one, it checks the 'ontimeout'
+ # value in the extlinux.conf file. If it's not present, then pick
+ # the first of the present systems.
+ def _get_default(self):
+ extlinux = os.path.join(self.mount_dir, 'extlinux.conf')
+ with open(extlinux, 'r') as f:
+ for line in f:
+ line = line.rstrip('\n')
+ key, value= line.split(' ', 1)
+ if key == "ontimeout":
+ return value
+ if key == "label":
+ break
+
+ return self.current_system
+
+ def _atomic_symlink_update(self, source, link_name):
+ dirname = os.path.dirname(link_name)
+ temp_dir = tempfile.mkdtemp(dir=dirname)
+ temp_link = os.path.join(temp_dir, 'temp_link')
+ try:
+ os.symlink(source, temp_link)
+ os.rename(temp_link, link_name)
+ except (OSError, IOError):
+ shutil.rmtree(temp_dir)
+ raise
+ # By this time, temp_dir will be empty.
+ os.rmdir(temp_dir)
+
+ def _rewrite_boot_menu(self, device, default, systems):
+ # Logic copied from morphlib.SaveFile to not create
+ # a morphlib dependency.
+ fd, temp_config = tempfile.mkstemp(dir=self.mount_dir)
+ os.close(fd)
+ config = os.path.join(self.mount_dir, 'extlinux.conf')
+ with open(temp_config, 'w') as f:
+ f.write('default menu.c32\n')
+ f.write('timeout 50\n')
+ f.write('prompt 0\n')
+ f.write('ontimeout ' + default +'\n')
+ for system in systems:
+ f.write('label ' + system +'\n')
+ f.write('kernel /systems/'+ system +'/kernel\n')
+ f.write('append root='+ device +' '
+ 'rootflags=subvol=systems/'+ system +'/run '
+ 'init=/sbin/init rw\n')
+ os.rename(temp_config, config)
+
+ default_path = os.path.join(self.mount_dir, 'systems', 'default')
+ default_path_tmp = os.path.join(self.mount_dir, 'systems', 'default-tmp')
+ if os.path.islink(default_path):
+ os.symlink(default, default_path_tmp)
+ os.rename(default_path_tmp, default_path)
+
+ def cmd_list(self):
+ for system in self._get_systems():
+ print system
+
+ def cmd_get_default(self):
+ print self._get_default()
+
+ def cmd_get_running(self):
+ print self.current_system
+
+ def _parse_deploy_location(self, location):
+ label, snapshot = os.path.split(location)
+ root, label = os.path.split(label)
+ if root != '/systems' or snapshot != 'orig':
+ raise AppException(
+ "Invalid deploy location %s. Upgrades should be deployed "
+ "from a Btrfs snapshot following the pattern: "
+ "/systems/$LABEL/orig" % location)
+ return label
+
+ def cmd_deploy(self, location):
+ '''Client-side deployment of a new base OS version.
+
+ This code assumes that the 'orig' subvolume has been correctly created
+ already. In future it could be extended to receive a delta of the
+ upgraded version over network somehow.
+
+ '''
+
+ label = self._parse_deploy_location(location)
+ version_root = os.path.join(self.mount_dir, 'systems', label)
+
+ orig_dir = os.path.join(version_root, 'orig')
+ run_dir = os.path.join(version_root, 'run')
+ try:
+ self.status(msg="Creating 'run' subvolume")
+ subprocess.check_call(
+ ['btrfs', 'subvolume', 'snapshot', orig_dir, run_dir])
+
+ self.status(msg='Updating system configuration')
+ log = os.path.join('/var', 'log', 'baserock-system-config-sync.log')
+
+ with open(log, 'w') as f:
+ subprocess.check_call(
+ ['baserock-system-config-sync', 'merge',
+ self.current_system, label], stdout=f)
+
+ # Copy the content of /var of the system deployed.
+ state_dir = os.path.join(self.mount_dir, 'state')
+ shared_var = os.path.join(state_dir, 'var')
+ new_var=os.path.join(run_dir, 'var')
+
+ for file in os.listdir(new_var):
+ subprocess.call(['cp', '-a', os.path.join(new_var, file), shared_var])
+
+ self.status(msg="Installing the kernel")
+ self._install_kernel(version_root)
+
+ except Exception as e:
+ # We are not controlling if deleting the suvolume fails
+ subprocess.call(['btrfs', 'subvolume', 'delete', run_dir])
+ raise
+
+ self._rewrite_boot_menu(self.device, self._get_default(), self._get_systems())
+
+ def _install_kernel(self, version_root):
+ '''Install the kernel outside of 'orig' or 'run' subvolumes
+
+ This code is kind of duplicated in morphlib/writeexts.py.
+
+ '''
+ image_names = ['vmlinuz', 'zImage', 'uImage']
+ kernel_dest = os.path.join(version_root, 'kernel')
+ for name in image_names:
+ try_path = os.path.join(version_root, 'run', 'boot', name)
+ if os.path.exists(try_path):
+ shutil.copy2(try_path, kernel_dest)
+ break
+
+ def _get_mount_info(self):
+ mountpoint = subprocess.check_output(
+ ['findmnt', '/', '-l', '-n', '-o', 'SOURCE'])
+ device, subvolume = mountpoint.split('[', 1)
+ subvolume = subvolume.split('/run', 1)[0]
+ current_system = os.path.basename(subvolume)
+
+ # Following the symlink of the device.
+ device = os.path.realpath(device)
+ return device, current_system
+
+ def cmd_remove (self, system_name):
+ self._check_system_exists(system_name)
+
+ default_system = self._get_default()
+
+ if system_name == default_system:
+ sys.stderr.write("ERROR: you can't remove the default system\n")
+ sys.exit(1)
+ if system_name == self.current_system:
+ sys.stderr.write("ERROR: you can't remove the running system\n")
+ sys.exit(1)
+
+ self.status(msg="Removing system: %s" % system_name)
+ system_root = os.path.join(self.mount_dir, 'systems', system_name)
+
+ # We are not controlling if deleting the suvolume fails
+ subprocess.call(['btrfs', 'subvolume', 'delete',
+ os.path.join(system_root, 'run')])
+ subprocess.call(['btrfs', 'subvolume', 'delete',
+ os.path.join(system_root, 'orig')])
+ shutil.rmtree(system_root)
+
+ self._rewrite_boot_menu(self.device, default_system, self._get_systems())
+
+ def cmd_set_default (self, system_name):
+ self._check_system_exists(system_name)
+ self._rewrite_boot_menu(self.device, system_name, self._get_systems())
+
+ def mount_fs(self):
+ subprocess.check_call(['mount', self.device, self.mount_dir])
+
+ def umount_fs(self):
+ subprocess.call(['umount', self.mount_dir])
+
+ def _check_system_compatibility(self):
+ menu_file = os.path.join(self.mount_dir, 'menu.c32')
+ if not os.path.isfile(menu_file):
+ raise SystemNotCompatibleError("menu.c32 not found")
+
+ def run(self):
+ args = self.args
+ action = args.action
+
+ self.mount_fs()
+ try:
+ self._check_system_compatibility()
+
+ if action == "list":
+ self.cmd_list()
+ elif action == "deploy":
+ self.cmd_deploy(args.location)
+ elif action == "remove":
+ self.cmd_remove(args.system_name)
+ elif action == "set-default":
+ self.cmd_set_default(args.system_name)
+ elif action == "get-default":
+ self.cmd_get_default()
+ elif action == "get-running":
+ self.cmd_get_running()
+ else:
+ raise NotImplementedError("Unknown command %s" % action)
+ except SystemNotCompatibleError, e:
+ sys.stderr.write("ERROR, system not compatible: %s\n" % e.args[0])
+ raise
+ finally:
+ self.umount_fs()
+
+mount_dir = tempfile.mkdtemp()
+try:
+ SystemVersionManager(sys.argv, mount_dir).run()
+finally:
+ os.rmdir(mount_dir)