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[Qemu-devel] [PATCH 2/2] backup: QEMU Backup Tool
From: |
Ishani Chugh |
Subject: |
[Qemu-devel] [PATCH 2/2] backup: QEMU Backup Tool |
Date: |
Fri, 11 Aug 2017 18:34:00 +0530 |
qemu-backup will be a command-line tool for performing full and
incremental disk backups on running VMs. It is intended as a
reference implementation for management stack and backup developers
to see QEMU's backup features in action. The tool writes details of
guest in a configuration file and the data is retrieved from the file
while creating a backup. The location of config file can be set as an
environment variable QEMU_BACKUP_CONFIG. The usage is as follows:
Add a guest
python qemu-backup.py guest add --guest <guest_name> --qmp <socket_path>
Add a drive for backup in a specified guest
python qemu-backup.py drive add --guest <guest_name> --id <drive_id> [--target
<target_file_path>]
Create backup of the added drives:
python qemu-backup.py backup --guest <guest_name>
List all guest configs in configuration file:
python qemu-backup.py guest list
Restore operation
python qemu-backup.py restore --guest <guest-name>
Remove a guest
python qemu-backup.py guest remove --guest <guest_name>
Signed-off-by: Ishani Chugh <address@hidden>
---
contrib/backup/qemu-backup.py | 309 ++++++++++++++++++++++++++++++++++++++++++
1 file changed, 309 insertions(+)
create mode 100644 contrib/backup/qemu-backup.py
diff --git a/contrib/backup/qemu-backup.py b/contrib/backup/qemu-backup.py
new file mode 100644
index 0000000..9bbbdb7
--- /dev/null
+++ b/contrib/backup/qemu-backup.py
@@ -0,0 +1,309 @@
+#!/usr/bin/python
+# -*- coding: utf-8 -*-
+#
+# Copyright (C) 2013 Red Hat, Inc.
+#
+# 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; either version 2 of the License, or
+# (at your option) any later version.
+#
+# 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 <http://www.gnu.org/licenses/>.
+#
+
+"""
+This file is an implementation of backup tool
+"""
+from __future__ import print_function
+from argparse import ArgumentParser
+import os
+import errno
+from socket import error as socket_error
+try:
+ import configparser
+except ImportError:
+ import ConfigParser as configparser
+import sys
+sys.path.append(os.path.join(os.path.dirname(__file__), '..', '..',
+ 'scripts', 'qmp'))
+from qmp import QEMUMonitorProtocol
+
+
+class BackupTool(object):
+ """BackupTool Class"""
+ def __init__(self,
+ config_file=os.path.expanduser('~')+'/.qemu/backup/config'):
+ if "QEMU_BACKUP_CONFIG" in os.environ:
+ self.config_file = os.environ["QEMU_BACKUP_CONFIG"]
+ else:
+ self.config_file = config_file
+ try:
+ if not os.path.isdir(os.path.expanduser('~')+'/.qemu/backup'):
+ os.makedirs(os.path.expanduser('~')+'/.qemu/backup')
+ except:
+ print("Cannot find the config file", file=sys.stderr)
+ exit(1)
+ self.config = configparser.ConfigParser()
+ self.config.read(self.config_file)
+
+ def write_config(self):
+ """
+ Writes configuration to ini file.
+ """
+ config_file = open(self.config_file+".tmp", 'w')
+ self.config.write(config_file)
+ config_file.flush()
+ os.fsync(config_file.fileno())
+ config_file.close()
+ os.rename(self.config_file+".tmp", self.config_file)
+
+ def get_socket_address(self, socket_address):
+ """
+ Return Socket address in form of string or tuple
+ """
+ if socket_address.startswith('tcp'):
+ return (socket_address.split(':')[1],
+ int(socket_address.split(':')[2]))
+ return socket_address.split(':',2)[1]
+
+ def _full_backup(self, guest_name):
+ """
+ Performs full backup of guest
+ """
+ if guest_name not in self.config.sections():
+ print ("Cannot find specified guest", file=sys.stderr)
+ exit(1)
+
+ self.verify_guest_running(guest_name)
+ connection = QEMUMonitorProtocol(
+ self.get_socket_address(
+ self.config[guest_name]['qmp']))
+ connection.connect()
+ cmd = {"execute": "transaction", "arguments": {"actions": []}}
+ for key in self.config[guest_name]:
+ if key.startswith("drive_"):
+ drive = key[len('drive_'):]
+ target = self.config[guest_name][key]
+ sub_cmd = {"type": "drive-backup", "data": {"device": drive,
+ "target": target,
+ "sync": "full"}}
+ cmd['arguments']['actions'].append(sub_cmd)
+ connection.cmd_obj(cmd)
+ if connection.pull_event(wait=True)['event'] == 'BLOCK_JOB_COMPLETED':
+ print("Backup Complete")
+ else:
+ print("Cannot complete backup", file=sys.stderr)
+
+ def _drive_add(self, drive_id, guest_name, target=None):
+ """
+ Adds drive for backup
+ """
+ if target is None:
+ target = os.path.abspath(drive_id)
+
+ if guest_name not in self.config.sections():
+ print ("Cannot find specified guest", file=sys.stderr)
+ exit(1)
+
+ if "drive_"+drive_id in self.config[guest_name]:
+ print ("Drive already marked for backup", file=sys.stderr)
+ exit(1)
+
+ self.verify_guest_running(guest_name)
+
+ connection = QEMUMonitorProtocol(
+ self.get_socket_address(
+ self.config[guest_name]['qmp']))
+ connection.connect()
+ cmd = {'execute': 'query-block'}
+ returned_json = connection.cmd_obj(cmd)
+ device_present = False
+ for device in returned_json['return']:
+ if device['device'] == drive_id:
+ device_present = True
+ break
+
+ if not device_present:
+ print ("No such drive in guest", file=sys.stderr)
+ sys.exit(1)
+
+ drive_id = "drive_" + drive_id
+ for d_id in self.config[guest_name]:
+ if self.config[guest_name][d_id] == target:
+ print ("Please choose different target", file=sys.stderr)
+ exit(1)
+ self.config.set(guest_name, drive_id, target)
+ self.write_config()
+ print("Successfully Added Drive")
+
+ def verify_guest_running(self, guest_name):
+ """
+ Checks whether specified guest is running or not
+ """
+ socket_address = self.config.get(guest_name, 'qmp')
+ try:
+ connection = QEMUMonitorProtocol(self.get_socket_address(
+ socket_address))
+ connection.connect()
+ except socket_error:
+ if socket_error.errno != errno.ECONNREFUSED:
+ print ("Connection to guest refused", file=sys.stderr)
+ sys.exit(1)
+
+ def _guest_add(self, guest_name, socket_address):
+ """
+ Adds a guest to the config file
+ """
+ if guest_name in self.config.sections():
+ print ("ID already exists. Please choose a different guestname",
+ file=sys.stderr)
+ sys.exit(1)
+ self.config[guest_name] = {'qmp': socket_address}
+ self.verify_guest_running(guest_name)
+ self.write_config()
+ print("Successfully Added Guest")
+
+ def _guest_remove(self, guest_name):
+ """
+ Removes a guest from config file
+ """
+ if guest_name not in self.config.sections():
+ print("Guest Not present", file=sys.stderr)
+ sys.exit(1)
+ self.config.remove_section(guest_name)
+ print("Guest successfully deleted")
+
+ def _restore(self, guest_name):
+ """
+ Prints Steps to perform restore operation
+ """
+ if guest_name not in self.config.sections():
+ print ("Cannot find specified guest", file=sys.stderr)
+ exit(1)
+
+ self.verify_guest_running(guest_name)
+ connection = QEMUMonitorProtocol(
+ self.get_socket_address(
+ self.config[guest_name]['qmp']))
+ connection.connect()
+ print("To perform restore, replace:")
+ for key in self.config[guest_name]:
+ if key.startswith("drive_"):
+ drive = key[len('drive_'):]
+ target = self.config[guest_name][key]
+ cmd = {'execute': 'query-block'}
+ returned_json = connection.cmd_obj(cmd)
+ device_present = False
+ for device in returned_json['return']:
+ if device['device'] == drive:
+ device_present = True
+ location = device['inserted']['image']['filename']
+ print(location+" By "+target)
+
+ if not device_present:
+ print ("No such drive in guest", file=sys.stderr)
+ sys.exit(1)
+
+ def guest_remove_wrapper(self, args):
+ """
+ Wrapper for _guest_remove method.
+ """
+ guest_name = args.guest
+ self._guest_remove(guest_name)
+ self.write_config()
+
+ def list(self, args):
+ """
+ Prints guests present in Config file
+ """
+ for guest_name in self.config.sections():
+ print(guest_name)
+
+ def guest_add_wrapper(self, args):
+ """
+ Wrapper for _quest_add method
+ """
+ self._guest_add(args.guest, args.qmp)
+
+ def drive_add_wrapper(self, args):
+ """
+ Wrapper for _drive_add method
+ """
+ self._drive_add(args.id, args.guest, args.target)
+
+ def fullbackup_wrapper(self, args):
+ """
+ Wrapper for _full_backup method
+ """
+ self._full_backup(args.guest)
+
+ def restore_wrapper(self, args):
+ """
+ Wrapper for restore
+ """
+ self._restore(args.guest)
+
+
+def main():
+ backup_tool = BackupTool()
+ parser = ArgumentParser()
+ subparsers = parser.add_subparsers(title='Subcommands',
+ description='Valid Subcommands',
+ help='Subcommand help')
+ guest_parser = subparsers.add_parser('guest', help='Adds or \
+ removes and lists guest(s)')
+ guest_subparsers = guest_parser.add_subparsers(title='Guest Subparser')
+ guest_list_parser = guest_subparsers.add_parser('list',
+ help='Lists all guests')
+ guest_list_parser.set_defaults(func=backup_tool.list)
+
+ guest_add_parser = guest_subparsers.add_parser('add', help='Adds a guest')
+ guest_add_parser.add_argument('--guest', action='store', type=str,
+ help='Name of the guest')
+ guest_add_parser.add_argument('--qmp', action='store', type=str,
+ help='Path of socket')
+ guest_add_parser.set_defaults(func=backup_tool.guest_add_wrapper)
+
+ guest_remove_parser = guest_subparsers.add_parser('remove',
+ help='removes a guest')
+ guest_remove_parser.add_argument('--guest', action='store', type=str,
+ help='Name of the guest')
+ guest_remove_parser.set_defaults(func=backup_tool.guest_remove_wrapper)
+
+ drive_parser = subparsers.add_parser('drive',
+ help='Adds drive(s) for backup')
+ drive_subparsers = drive_parser.add_subparsers(title='Add subparser',
+ description='Drive \
+ subparser')
+ drive_add_parser = drive_subparsers.add_parser('add',
+ help='Adds new \
+ drive for backup')
+ drive_add_parser.add_argument('--guest', action='store',
+ type=str, help='Name of the guest')
+ drive_add_parser.add_argument('--id', action='store',
+ type=str, help='Drive ID')
+ drive_add_parser.add_argument('--target', nargs='?',
+ default=None, help='Destination path')
+ drive_add_parser.set_defaults(func=backup_tool.drive_add_wrapper)
+
+ backup_parser = subparsers.add_parser('backup', help='Creates backup')
+ backup_parser.add_argument('--guest', action='store',
+ type=str, help='Name of the guest')
+ backup_parser.set_defaults(func=backup_tool.fullbackup_wrapper)
+
+ backup_parser = subparsers.add_parser('restore', help='Restores drives')
+ backup_parser.add_argument('--guest', action='store',
+ type=str, help='Name of the guest')
+ backup_parser.set_defaults(func=backup_tool.restore_wrapper)
+
+ args = parser.parse_args()
+ args.func(args)
+
+if __name__ == '__main__':
+ main()
--
2.7.4