This is a Request For Comments patch for qemu backup tool. As an
Outreachy intern, I am assigned to the project for creating a backup
tool. 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 usage is as follows:
Add a guest
python qemu-backup.py guest add --guest <guest_name> --qmp <socket_path> [--tcp]
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
I will be obliged by any feedback.
Signed-off-by: Ishani Chugh <chugh.ish...@research.iiit.ac.in>
---
contrib/backup/qemu-backup.py | 244 ++++++++++++++++++++++++++++++++++++++++++
1 file changed, 244 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..9c3dc53
--- /dev/null
+++ b/contrib/backup/qemu-backup.py
@@ -0,0 +1,244 @@
+#!/usr/bin/python
+# -*- coding: utf-8 -*-
+"""
+This file is an implementation of backup tool
+"""
+from argparse import ArgumentParser
+import os
+import errno
+from socket import error as socket_error
+import configparser
+import sys
+sys.path.append('../../scripts/qmp')
+from qmp import QEMUMonitorProtocol
+
+
+class BackupTool(object):
+ """BackupTool Class"""
+ def __init__(self, config_file='backup.ini'):
+ self.config_file = config_file
+ self.config = configparser.ConfigParser()
+ self.config.read(self.config_file)
+
+ def write_config(self):
+ """
+ Writes configuration to ini file.
+ """
+ with open(self.config_file, 'w') as config_file:
+ self.config.write(config_file)
+
+ def get_socket_path(self, socket_path, tcp):
+ """
+ Return Socket address in form of string or tuple
+ """
+ if tcp is False:
+ return os.path.abspath(socket_path)
+ return (socket_path.split(':')[0], int(socket_path.split(':')[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")
+ return
+ if self.is_guest_running(guest_name, self.config[guest_name]['qmp'],
+ self.config[guest_name]['tcp']) is False:
+ return
+ connection = QEMUMonitorProtocol(
+ self.get_socket_path(
+ self.config[guest_name]['qmp'],
+ self.config[guest_name]['tcp']))
+ connection.connect()
+ cmd = {"execute": "transaction", "arguments": {"actions": []}}
+ for key in self.config[guest_name]:
+ if key.startswith("drive_"):
+ drive = key[key.index('_')+1:]
+ target = self.config[guest_name][key]
+ sub_cmd = {"type": "drive-backup", "data": {"device": drive,
+ "target": target,
+ "sync": "full"}}
+ cmd['arguments']['actions'].append(sub_cmd)
+ print (connection.cmd_obj(cmd))
+
+ def __drive_add(self, drive_id, guest_name, target=None):
+ """
+ Adds drive for backup
+ """
+ if target is None:
+ target = os.path.abspath(drive_id) + ".img"
+
+ if guest_name not in self.config.sections():
+ print ("Cannot find specified guest")
+ return
+
+ if "drive_"+drive_id in self.config[guest_name]:
+ print ("Drive already marked for backup")
+ return
+
+ if self.is_guest_running(guest_name, self.config[guest_name]['qmp'],
+ self.config[guest_name]['tcp']) is False:
+ return
+
+ connection = QEMUMonitorProtocol(
+ self.get_socket_path(
+ self.config[guest_name]['qmp'],
+ self.config[guest_name]['tcp']))
+ 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 device_present is False:
+ print ("No such drive in guest")
+ return
+
+ drive_id = "drive_" + drive_id
+ for id in self.config[guest_name]:
+ if self.config[guest_name][id] == target:
+ print ("Please choose different target")
+ return
+ self.config.set(guest_name, drive_id, target)
+ self.write_config()
+ print("Successfully Added Drive")
+
+ def is_guest_running(self, guest_name, socket_path, tcp):
+ """
+ Checks whether specified guest is running or not
+ """
+ try:
+ connection = QEMUMonitorProtocol(
+ self.get_socket_path(
+ socket_path, tcp))
+ connection.connect()
+ except socket_error:
+ if socket_error.errno != errno.ECONNREFUSED:
+ print ("Connection to guest refused")
+ return False
+ except:
+ print ("Unable to connect to guest")
+ return False
+ return True
+
+ def __guest_add(self, guest_name, socket_path, tcp):
+ """
+ Adds a guest to the config file
+ """
+ if self.is_guest_running(guest_name, socket_path, tcp) is False:
+ return
+
+ if guest_name in self.config.sections():
+ print ("ID already exists. Please choose a different guestname")
+ return
+
+ self.config[guest_name] = {'qmp': socket_path}
+ self.config.set(guest_name, 'tcp', str(tcp))
+ 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")
+ return
+ self.config.remove_section(guest_name)
+ print("Guest successfully deleted")
+
+ 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
+ """
+ if args.tcp is False:
+ self.__guest_add(args.guest, args.qmp, False)
+ else:
+ self.__guest_add(args.guest, args.qmp, True)
+
+ 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 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.add_argument('--tcp', nargs='?', type=bool,
+ default=False,
+ help='Specify if socket is tcp')
+ 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)
+
+ args = parser.parse_args()
+ args.func(args)
+
+if __name__ == '__main__':
+ main()
--
2.7.4
